SYSTEMS AND METHODS FOR IMPROVED COMMUNICATION EFFICIENCY IN HIGH EFFICIENCY WIRELESS NETWORKS

Abstract

Methods and apparatus for adjusting transmission power in wireless networks are provided. One aspect of the disclosure provides a method of wireless communication over a wireless communication medium. The method includes determining a level of interference for a data transmission from a transmitting device to an intended receiving device. The method further includes setting a transmission power level for transmitting a message based on the interference level, the message comprising one of a request-to-send (RTS) packet and a clear-to-send (CTS) packet. The method further includes transmitting the message at the set transmission power level.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 61/897,135 entitled “SYSTEMS AND METHODS FOR IMPROVED COMMUNICATION EFFICIENCY IN HIGH EFFICIENCY WIRELESS NETWORKS” filed on Oct. 29, 2013 the disclosure of which is hereby incorporated by reference in its entirety. This application further claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 61/924,156, entitled “SYSTEMS AND METHODS FOR IMPROVED COMMUNICATION EFFICIENCY IN HIGH EFFICIENCY WIRELESS NETWORKS,” filed Jan. 6, 2014, assigned to the assignee hereof and incorporated herein by reference in its entirety. This application further claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 61/928,845, entitled “SYSTEMS AND METHODS FOR IMPROVED COMMUNICATION EFFICIENCY IN HIGH EFFICIENCY WIRELESS NETWORKS,” filed Jan. 17, 2014, assigned to the assignee hereof and incorporated herein by reference in its entirety.

FIELD

Certain aspects of the present disclosure generally relate to wireless communications, and more particularly, to methods and apparatus for adjusting transmission power in wireless networks.

BACKGROUND

In many telecommunication systems, communications networks are used to exchange messages among several interacting spatially-separated devices. Networks can be classified according to geographic scope, which could be, for example, a metropolitan area, a local area, or a personal area. Such networks can be designated respectively as a wide area network (WAN), metropolitan area network (MAN), local area network (LAN), or personal area network (PAN). Networks also differ according to the switching/routing technique used to interconnect the various network nodes and devices (e.g., circuit switching vs. packet switching), the type of physical media employed for transmission (e.g., wired vs. wireless), and the set of communication protocols used (e.g., Internet protocol suite, SONET (Synchronous Optical Networking), Ethernet, etc.).

Wireless networks are often preferred when the network elements are mobile and thus have dynamic connectivity needs, or if the network architecture is formed in an ad hoc, rather than fixed, topology. Wireless networks employ intangible physical media in an unguided propagation mode using electromagnetic waves in the radio, microwave, infra-red, optical, etc. frequency bands. Wireless networks advantageously facilitate user mobility and rapid field deployment when compared to fixed wired networks.

The devices in a wireless network can transmit/receive information between each other. Device transmissions can interfere with each other, and certain transmissions can selectively block other transmissions. Where many devices share a communication network, congestion and inefficient link usage can result. As such, systems, methods, and non-transitory computer-readable media are needed for improving communication efficiency in high efficiency wireless networks.

SUMMARY

Various implementations of systems, methods and devices within the scope of the appended claims each have several aspects, no single one of which is solely responsible for the desirable attributes described herein. Without limiting the scope of the appended claims, some prominent features are described herein.

Details of one or more implementations of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, the drawings, and the claims. Note that the relative dimensions of the following figures may not be drawn to scale.

One aspect of the disclosure provides a method of wireless communication over a wireless communication medium. The method includes determining a level of interference for a data transmission from a transmitting device to an intended receiving device. The method further includes setting a transmission power level for transmitting a message based on the interference level, the message comprising one of a request-to-send (RTS) packet and a clear-to-send (CTS) packet. The method further includes transmitting the message at the set transmission power level.

In various embodiments, the message reserving the wireless medium can include one of a request-to-send (RTS) packet and a clear-to-send (CTS) packet. In various embodiments, the transmission metric can include a packet error rate (PER).

In various embodiments, the method can further include identifying one or more potentially interfering devices. The method can further include ordering the potentially interfering devices based on an estimated transmit power to reach each potentially interfering device. The method can further include setting the transmission power for the message reserving the wireless medium further based on the ordering.

In various embodiments, setting the transmission power of the message reserving the wireless medium can include selecting a lowest estimated transmit power in the ordering, and selecting a next highest estimated transmit power in the ordering when the interference metric crosses a threshold value.

In various embodiments, identifying the one or more potentially interfering devices can include scanning for neighboring basic service sets (BSSs), transmitting a querying message to an intended recipient of the data transmission, and identifying devices included in a neighboring BSS, but not visible to or detected by the intended recipient of the data transmission, as potentially interfering devices.

In various embodiments, the estimated transmit power is based on a transmit power control (TPC) information element (IE) included in a beacon. In various embodiments, potentially interfering devices comprise devices producing acknowledgement (ACK) interference.

Another aspect provides an apparatus configured to perform wireless communication over a wireless communication medium. The apparatus includes a processor configured to determine a level of interference for a data transmission to an intended receiving device n. The processor is further configured to set a transmission power, for a message based on the interference level. The apparatus further includes a transmitter configured to transmit the message at the set transmission power level.

In various embodiments, the message reserving the wireless medium can include one of a request-to-send (RTS) packet and a clear-to-send (CTS) packet. In various embodiments, the transmission metric can include a packet error rate (PER).

In various embodiments, the processor can be further configured to identify one or more potentially interfering devices. The processor can be further configured to order the potentially interfering devices based on an estimated transmit power to reach each potentially interfering device. The processor can be further configured to set the transmission power for the message reserving the wireless medium further based on the ordering.

In various embodiments, the processor can be further configured to select a lowest estimated transmit power in the ordering. The processor can be further configured to select a next highest estimated transmit power in the ordering when the interference metric crosses a threshold value.

In various embodiments, the apparatus can further include a receiver configured to scan for neighboring basic service sets (BSSs). The transmitter can be further configured to transmit a querying message to an intended recipient of the data transmission. The processor can be further configured to identify devices included in a neighboring BSS, but not visible to or detected by the intended recipient of the data transmission, as potentially interfering devices.

In various embodiments, the estimated transmit power is based on a transmit power control (TPC) information element (IE) included in a beacon. In various embodiments, potentially interfering devices comprise devices producing acknowledgement (ACK) interference.

Another aspect provides an apparatus for wireless communication over a wireless communication medium. The apparatus includes means for determining a level of interference for a data transmission to an intended receiving device. The apparatus further includes means for setting a transmission power level for transmitting a message reserving the wireless medium, based on the interference level, the message comprising one of a request-to-send (RTS) packet and a clear-to-send (CTS) packet. The apparatus further includes means for transmitting the message at the set transmission power level.

In various embodiments, the message reserving the wireless medium can include one of a request-to-send (RTS) packet and a clear-to-send (CTS) packet. In various embodiments, the transmission metric can include a packet error rate (PER).

In various embodiments, the apparatus can further include means for identifying one or more potentially interfering devices. The apparatus can further include means for ordering the potentially interfering devices based on an estimated transmit power to reach each potentially interfering device. The apparatus can further include means for setting the transmission power for the message reserving the wireless medium further based on the ordering.

In various embodiments, means for setting the transmission power of the message reserving the wireless medium can include means for selecting a lowest estimated transmit power in the ordering and means for selecting a next highest estimated transmit power in the ordering when the interference metric crosses a threshold value.

In various embodiments, means for identifying the one or more potentially interfering devices can include means for scanning for neighboring basic service sets (BSSs), means for transmitting a querying message to an intended recipient of the data transmission, and means for identifying devices included in a neighboring BSS, but not visible to or detected by the intended recipient of the data transmission, as potentially interfering devices.

In various embodiments, the estimated transmit power is based on a transmit power control (TPC) information element (IE) included in a beacon. In various embodiments, potentially interfering devices comprise devices producing acknowledgement (ACK) interference.

Another aspect provides a non-transitory computer-readable medium. The medium includes code that, when executed, causes an apparatus to determine a level of interference for a data transmission from a transmitting device to an intended receiving device. The medium further includes code that, when executed, causes the apparatus to set a transmission power level for transmitting a message reserving the wireless medium, based on the interference level, the message comprising one of a request-to-send (RTS) packet and a clear-to-send (CTS) packet. The medium further includes code that, when executed, causes the apparatus to transmit the message the message at the set transmission power level.

In various embodiments, the message reserving the wireless medium can include one of a request-to-send (RTS) packet and a clear-to-send (CTS) packet. In various embodiments, the transmission metric can include a packet error rate (PER).

In various embodiments, the medium can further include code that, when executed, causes the apparatus to identify one or more potentially interfering devices. The medium can further include code that, when executed, causes the apparatus to order the potentially interfering devices based on an estimated transmit power to reach each potentially interfering device. The medium can further include code that, when executed, causes the apparatus to set the transmission power for the message reserving the wireless medium further based on the ordering.

In various embodiments, setting the transmission power of the message reserving the wireless medium can include selecting a lowest estimated transmit power in the ordering and selecting a next highest estimated transmit power in the ordering when the interference metric crosses a threshold value.

In various embodiments, identifying the one or more potentially interfering devices can include scanning for neighboring basic service sets (BSSs), transmitting a querying message to an intended recipient of the data transmission, and identifying devices included in a neighboring BSS, but not visible to or detected by the intended recipient of the data transmission, as potentially interfering devices.

In various embodiments, the estimated transmit power is based on a transmit power control (TPC) information element (IE) included in a beacon. In various embodiments, potentially interfering devices comprise devices producing acknowledgement (ACK) interference.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a wireless communication system in which aspects of the present disclosure can be employed.

FIG. 2 illustrates various components that can be utilized in a wireless device that can be employed within the wireless communication system of FIG. 1.

FIG. 3 is a diagram of an exemplary wireless communication system.

FIG. 4 is a diagram of an exemplary RTS/CTS exchange.

FIG. 5 is a diagram of an exemplary RTS/CTS exchange.

FIG. 6 is a time sequence diagram of the RTS/CTS exchange

FIG. 7 is a diagram of an exemplary RTS/CTS exchange in a wireless communication system.

FIG. 8 shows a flowchart for an exemplary method of wireless communication that can be employed within the wireless communication system of FIG. 1.

FIG. 9 shows a flowchart for an exemplary method of wireless communication that can be employed within the wireless communication system of FIG. 1.

DETAILED DESCRIPTION

Various aspects of the novel systems, apparatuses, and methods are described more fully hereinafter with reference to the accompanying drawings. The teachings disclosure can, however, be embodied in many different forms and should not be construed as limited to any specific structure or function presented throughout this disclosure. Rather, these aspects are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Based on the teachings herein one skilled in the art should appreciate that the scope of the disclosure is intended to cover any aspect of the novel systems, apparatuses, and methods disclosed herein, whether implemented independently of or combined with any other aspect of the invention. For example, an apparatus can be implemented or a method can be practiced using any number of the aspects set forth herein. In addition, the scope of the invention is intended to cover such an apparatus or method which is practiced using other structure, functionality, or structure and functionality in addition to or other than the various aspects of the invention set forth herein. It should be understood that any aspect disclosed herein can be embodied by one or more elements of a claim.

Although particular aspects are described herein, many variations and permutations of these aspects fall within the scope of the disclosure. Although some benefits and advantages of the preferred aspects are mentioned, the scope of the disclosure is not intended to be limited to particular benefits, uses, or objectives. Rather, aspects of the disclosure are intended to be broadly applicable to different wireless technologies, system configurations, networks, and transmission protocols, some of which are illustrated by way of example in the figures and in the following description of the preferred aspects. The detailed description and drawings are merely illustrative of the disclosure rather than limiting, the scope of the disclosure being defined by the appended claims and equivalents thereof.

Wireless network technologies can include various types of wireless local area networks (WLANs). A WLAN can be used to interconnect nearby devices together, employing widely used networking protocols. The various aspects described herein can apply to any communication standard, such as Wi-Fi or, more generally, any member of the IEEE 802.11 family of wireless protocols.

In some aspects, wireless signals can be transmitted according to a high-efficiency 802.11 protocol using orthogonal frequency-division multiplexing (OFDM), direct-sequence spread spectrum (DSSS) communications, a combination of OFDM and DSSS communications, or other schemes. Implementations of the high-efficiency 802.11 protocol can be used for Internet access, sensors, metering, smart grid networks, or other wireless applications. Advantageously, aspects of certain devices implementing this particular wireless protocol can consume less power than devices implementing other wireless protocols, can be used to transmit wireless signals across short distances, and/or can be able to transmit signals less likely to be blocked by objects, such as humans.

In some implementations, a WLAN includes various devices which are the components that access the wireless network. For example, there can be two types of devices: access points (“APs”) and clients (also referred to as stations, or “STAs”). In general, an AP serves as a hub or base station for the WLAN and an STA serves as a user of the WLAN. For example, a STA can be a laptop computer, a personal digital assistant (PDA), a mobile phone, etc. In an example, an STA connects to an AP via a Wi-Fi (e.g., IEEE 802.11 protocol such as 802.11ah) compliant wireless link to obtain general connectivity to the Internet or to other wide area networks. In some implementations an STA can also be used as an AP.

The techniques described herein can be used for various broadband wireless communication systems, including communication systems that are based on an orthogonal multiplexing scheme. Examples of such communication systems include Spatial Division Multiple Access (SDMA), Time Division Multiple Access (TDMA), Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single-Carrier Frequency Division Multiple Access (SC-FDMA) systems, and so forth. An SDMA system can utilize sufficiently different directions to concurrently transmit data belonging to multiple user terminals. A TDMA system can allow multiple user terminals to share the same frequency channel by dividing the transmission signal into different time slots, each time slot being assigned to different user terminal. A TDMA system can implement GSM or some other standards known in the art. An OFDMA system utilizes orthogonal frequency division multiplexing (OFDM), which is a modulation technique that partitions the overall system bandwidth into multiple orthogonal sub-carriers. These sub-carriers can also be called tones, bins, etc. With OFDM, each sub-carrier can be independently modulated with data. An OFDM system can implement IEEE 802.11 or some other standards known in the art. An SC-FDMA system can utilize interleaved FDMA (IFDMA) to transmit on sub-carriers that are distributed across the system bandwidth, localized FDMA (LFDMA) to transmit on a block of adjacent sub-carriers, or enhanced FDMA (EFDMA) to transmit on multiple blocks of adjacent sub-carriers. In general, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDMA. A SC-FDMA system can implement 3GPP-LTE (3rd Generation Partnership Project Long Term Evolution) or other standards.

The teachings herein can be incorporated into (e.g., implemented within or performed by) a variety of wired or wireless apparatuses (e.g., nodes). In some aspects, a wireless node implemented in accordance with the teachings herein can comprise an access point or an access terminal.

An access point (“AP”) can comprise, be implemented as, or known as a NodeB, Radio Network Controller (“RNC”), eNodeB, Base Station Controller (“BSC”), Base Transceiver Station (“BTS”), Base Station (“BS”), Transceiver Function (“TF”), Radio Router, Radio Transceiver, Basic Service Set (“BSS”), Extended Service Set (“ES S”), Radio Base Station (“RBS”), or some other terminology.

A station (“STA”) can also comprise, be implemented as, or known as a user terminal, an access terminal (“AT”), a subscriber station, a subscriber unit, a mobile station, a remote station, a remote terminal, a user agent, a user device, user equipment, or some other terminology. In some implementations an access terminal can comprise a cellular telephone, a cordless telephone, a Session Initiation Protocol (“SIP”) phone, a wireless local loop (“WLL”) station, a personal digital assistant (“PDA”), a handheld device having wireless connection capability, or some other suitable processing device connected to a wireless modem. Accordingly, one or more aspects taught herein can be incorporated into a phone (e.g., a cellular phone or smartphone), a computer (e.g., a laptop), a portable communication device, a headset, a portable computing device (e.g., a personal data assistant), an entertainment device (e.g., a music or video device, or a satellite radio), a gaming device or system, a global positioning system device, or any other suitable device that is configured to communicate via a wireless medium.

As discussed above, certain of the devices described herein can implement the 802.11ah standard, for example. Such devices, whether used as an STA or AP or other device, can be used for smart metering or in a smart grid network. Such devices can provide sensor applications or be used in home automation. The devices can instead or in addition be used in a healthcare context, for example for personal healthcare. They can also be used for surveillance, to enable extended-range Internet connectivity (e.g., for use with hotspots), or to implement machine-to-machine communications.

FIG. 1 illustrates an example of a wireless communication system 100 in which aspects of the present disclosure can be employed. The wireless communication system 100 can operate pursuant to a wireless standard, for example at least one of the 802.11ah, 802.11ac, 802.11n, 802.11g and 802.11b standards. The wireless communication system 100 can include an AP 104, which communicates with STAs 106.

A variety of processes and methods can be used for transmissions in the wireless communication system 100 between the AP 104 and the STAs 106. For example, signals can be transmitted and received between the AP 104 and the STAs 106 in accordance with OFDM/OFDMA techniques. If this is the case, the wireless communication system 100 can be referred to as an OFDM/OFDMA system. Alternatively, signals can be transmitted and received between the AP 104 and the STAs 106 in accordance with CDMA techniques. If this is the case, the wireless communication system 100 can be referred to as a CDMA system.

A communication link that facilitates transmission from the AP 104 to one or more of the STAs 106 can be referred to as a downlink (DL) 108, and a communication link that facilitates transmission from one or more of the STAs 106 to the AP 104 can be referred to as an uplink (UL) 110. Alternatively, a downlink 108 can be referred to as a forward link or a forward channel, and an uplink 110 can be referred to as a reverse link or a reverse channel.

The AP 104 can provide wireless communication coverage in a basic service area (BSA) 102. The AP 104 along with the STAs 106 associated with the AP 104 and that use the AP 104 for communication can be referred to as a basic service set (BSS). It should be noted that the wireless communication system 100 may not have a central AP 104, but rather can function as a peer-to-peer network between the STAs 106. Accordingly, the functions of the AP 104 described herein can alternatively be performed by one or more of the STAs 106.

FIG. 2 illustrates various components that can be utilized in a wireless device 202 that can be employed within the wireless communication system 100. The wireless device 202 is an example of a device that can be configured to implement the various methods described herein. For example, the wireless device 202 can comprise the AP 104 or one of the STAs 106.

The wireless device 202 can include a processor 204 which controls operation of the wireless device 202. The processor 204 can also be referred to as a central processing unit (CPU). Memory 206, which can include both read-only memory (ROM) and random access memory (RAM), provides instructions and data to the processor 204. A portion of the memory 206 can also include non-volatile random access memory (NVRAM). The processor 204 typically performs logical and arithmetic operations based on program instructions stored within the memory 206. The instructions in the memory 206 can be executable to implement the methods described herein.

The processor 204 can comprise or be a component of a processing system implemented with one or more processors. The one or more processors can be implemented with any combination of general-purpose microprocessors, microcontrollers, digital signal processors (DSPs), field programmable gate array (FPGAs), programmable logic devices (PLDs), controllers, state machines, gated logic, discrete hardware components, dedicated hardware finite state machines, or any other suitable entities that can perform calculations or other manipulations of information.

The processing system can also include machine-readable media for storing software. Software shall be construed broadly to mean any type of instructions, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Instructions can include code (e.g., in source code format, binary code format, executable code format, or any other suitable format of code). The instructions, when executed by the one or more processors, cause the processing system to perform the various functions described herein.

The wireless device 202 can also include a housing 208 that can include a transmitter 210 and a receiver 212 to allow transmission and reception of data between the wireless device 202 and a remote location. The transmitter 210 and receiver 212 can be combined into a transceiver 214. An antenna 216 can be attached to the housing 208 and electrically coupled to the transceiver 214. The wireless device 202 can also include (not shown) multiple transmitters, multiple receivers, multiple transceivers, and/or multiple antennas, which can be utilized during MIMO communications, for example.

The wireless device 202 can also include a signal detector 218 that can be used in an effort to detect and quantify the level of signals received by the transceiver 214. The signal detector 218 can detect such signals as total energy, energy per subcarrier per symbol, power spectral density and other signals. The wireless device 202 can also include a digital signal processor (DSP) 220 for use in processing signals. The DSP 220 can be configured to generate a data unit for transmission. In some aspects, the data unit can comprise a physical layer data unit (PPDU). In some aspects, the PPDU is referred to as a packet.

The wireless device 202 can further comprise a user interface 222 in some aspects. The user interface 222 can comprise a keypad, a microphone, a speaker, and/or a display. The user interface 222 can include any element or component that conveys information to a user of the wireless device 202 and/or receives input from the user.

The various components of the wireless device 202 can be coupled together by a bus system 226. The bus system 226 can include a data bus, for example, as well as a power bus, a control signal bus, and a status signal bus in addition to the data bus. Those of skill in the art will appreciate the components of the wireless device 202 can be coupled together or accept or provide inputs to each other using some other mechanism.

Although a number of separate components are illustrated in FIG. 2, those of skill in the art will recognize that one or more of the components can be combined or commonly implemented. For example, the processor 204 can be used to implement not only the functionality described above with respect to the processor 204, but also to implement the functionality described above with respect to the signal detector 218 and/or the DSP 220. Further, each of the components illustrated in FIG. 2 can be implemented using a plurality of separate elements.

As discussed above, the wireless device 202 can comprise an AP 104 or an STA 106, and can be used to transmit and/or receive communications. The communications exchanged between devices in a wireless network can include data units which can comprise packets or frames. In some aspects, the data units can include data frames, control frames, and/or management frames. Data frames can be used for transmitting data from an AP and/or a STA to other APs and/or STAs. Control frames can be used together with data frames for performing various operations and for reliably delivering data (e.g., acknowledging receipt of data, polling of APs, area-clearing operations, channel acquisition, carrier-sensing maintenance functions, etc.). Management frames can be used for various supervisory functions (e.g., for joining and departing from wireless networks, etc.).

Certain aspects of the present disclosure support allowing APs 104 to schedule STAs 106 transmissions in optimized ways to improve efficiency. Both high efficiency wireless (HEW) stations, stations utilizing an 802.11 high efficiency protocol, and stations using older or legacy 802.11 protocols, can compete for access to a wireless medium. The high-efficiency 802.11 protocol described herein can allow for devices to operate under a modified mechanism that differentiates between devices that can communicate concurrently and devices that cannot communicate concurrently. Accordingly, in the case of apartment buildings or densely-populated public spaces, APs and/or STAs that use the high-efficiency 802.11 protocol can experience reduced latency and increased network throughput even as the number of active wireless devices increases, thereby improving user experience.

In some embodiments, APs 104 can control access to a wireless medium by transmitting a message using a transmission characteristic such that at least the wireless devices to be silenced can decode the message and a second group of wireless devices can access the medium for transmissions. For example, with respect to FIG. 1, STAs 106a and 106b can be legacy STAs and 106c and 106d can be HEW STAs. In this embodiment, it can be desirable to silence the STAs 106a and 106b so that the STAs 106c and 106d can communicate with the AP 104 without interference from legacy STAs 106a and 106b. Thus, the transmission characteristic can be such that at least the STAs 106a and 106b can decode the message. When the STAs 106a and 106b detect the message, the STAs 106a and 106b can be silenced for the interval as identified by the duration field within the message. The duration field of the message can be set such that a predetermined percentage of a total communication time is reserved for the STAs 106c and 106d to communicate. The STAs 106c and 106d can also be able to decode the message but can receive an instruction to not set their network allocation vector (NAV) and thus not be silenced for the interval identified in the duration field of the message.

In some aspects, an AP 104 or a STA 106 can transmit a message with a transmission characteristic that reserves the medium for only HEW STAs or a group of HEW STAs by sending a message that sets the NAV for the legacy STAs but not for the HEW STAs. In other aspects, an AP 104 or a STA 106 can transmit a message with a transmission characteristic that reserves the medium for only legacy STAs or a group of legacy STAs by sending a message that sets the NAV of the HEW STAs but not the legacy STAs. This would allow the AP 104 to more efficiently allocate access to the medium between the HEW STAs and the legacy STAs.

In one embodiment, the transmission characteristic can be a new frame format with a new type and new subtype. In this implementation, with respect to FIG. 1, the STAs 106a and 106b can be operating in a mode according to a legacy IEEE 802.11 standard (i.e. IEEE 802.11b) and STAs 106c and 106d can be operating in a mode according to a IEEE 802.11 high efficiency protocol. In one embodiment, the new frame can have a similar structure as an 802.11b (or similar protocol) frame such that legacy STAs 106a and 106b can be able to decode the NAV for this new frame irrespective of the new type and subtype. The STAs 106a and 106b can then set their NAV according to the new frame. The HEW STAs 106c and 106d, on the other hand, can decode the new frame but determine that for this new frame type, as indicated by the type or subtype field, they can ignore the NAV for the new frame and thus can send transmissions during the time indicated by the duration field of the new frame. In some embodiments, the new frame format can be only decodable by one group of STAs (i.e. the new frame is not decodable by legacy stations). In this implementation, with respect to FIG. 1, the STAs 106a and 106b can be operating in a mode according to a legacy IEEE 802.11 standard (i.e. IEEE 802.11b) and STAs 106c and 106d can be operating in a mode according to a IEEE 802.11 high efficiency protocol. In this embodiment, the new frame may only be decodable by STAs 106c and 106d. The STAs 106c and 106d can then set their NAV according to the new frame while the STAs 106a and 106b can be unable to decode the new frame and thus can send transmissions as if medium was idle. In some embodiments, the new frame can also indicate a group of HEW STAs that can set their NAV or a group of HEW stations that can ignore the NAV, which can reserve the medium for a certain group of HEW stations. For example, the new frame can include an indication that STA 106c should set its NAV while STA 106d can ignore the NAV and transmit freely. In some aspects the new frame format can be similar to the format of a request to send (RTS), clear to send (CTS) or a QoS null frame.

In some embodiments, the transmission characteristic can be information in a field of an existing frame format. In one aspect, the AP 104 can transmit a clear-to-send (CTS)-to-self frame. In one embodiment, the AP 104 can set the receiver address (RA) of the CTS frame to a multicast address or to a specific medium access control (MAC) address to indicate to a first group of STAs to ignore the NAV of the CTS frame while a second group of STAs can set their NAV according to the CTS frame. For example, with respect to FIG. 1, STAs 106a and 106b can be legacy STAs and 106c and 106d can be HEW STAs. The STAs 106a and 106b can set their NAV according to the CTS, while the HEW STAs 106c and 106d, on the other hand, can see the RA multicast address as an indication to not set their NAV and can thereby be able to transmit during the duration of the CTS. In another embodiment, the AP 104 can set the receiver address (RA) of the CTS frame to a multicast address or to a specific medium access control (MAC) address and use one of the bits in the scrambling sequence in the service field of the CTS frame to indicate to a first group of STAs to ignore the NAV of the CTS frame while a second set of STAs can set their NAV according to the CTS frame.

In another aspect, the AP 104 can transmit a request to send (RTS) frame. In one embodiment, the AP 104 can set the transmitter address (TA) to a multicast address and use one of the bits in the scrambling sequence in the service field of the RTS to indicate to a first group of STAs to ignore the NAV of the RTS frame while a second group of STAs can set their NAV according to the RTS frame. For example, with respect to FIG. 1, STAs 106a and 106b can be legacy STAs and 106c and 106d can be HEW STAs. The STAs 106a and 106b can set their NAV according to the RTS, while the HEW STAs 106c and 106d, on the other hand, can see the TA multicast address and the use of the one bit in the service field as an indication to not set their NAV and can thereby be able to transmit during the duration of the RTS. In other embodiments, the AP 104 can transmit any data or management frame and set the TA to a multicast address and use one of the bits in the scrambling sequence in the service field of the data or management frame to indicate to a first group of STAs to ignore the NAV of the data or management frame while a second group of STAs can set their NAV according to the data or management frame.

In another aspect, an AP 104 or a STA 106 can transmit a quality of service (QoS) frame. In one embodiment, the AP 104 can use a one bit indication in the reserved bits of the QoS control field to indicate to a first group of STAs to ignore the NAV of the QoS frame while a second group of STAs can set their NAV according to the QoS frame. For example, with respect to FIG. 1, STAs 106a and 106b can be legacy STAs and 106c and 106d can be HEW STAs. The STAs 106a and 106b can set their NAV according to the QoS, while the HEW STAs 106c and 106d, on the other hand, can see the one bit indication in the control field as an indication to not set their NAV and can thereby be able to transmit during the duration of the QoS.

In another aspect, the AP 104 can transmit a control wrapper frame. In some embodiments the control wrapper frame can carry an RTS or CTS frame. In one embodiment, the AP 104 can use an invalid field setting in the high throughput control field of the control wrapper frame to indicate to a first group of STAs to ignore the NAV of the control wrapper frame while a second group of STAs can set their NAV according to the control wrapper frame. For example, with respect to FIG. 1, STAs 106a and 106b can be legacy STAs and 106c and 106d can be HEW STAs. The STAs 106a and 106b can set their NAV according to the control wrapper frame (with a RTS, CTS, or other frame), while the HEW STAs 106c and 106d, on the other hand, can see the invalid field settings in the high throughput control field as an indication to not set their NAV and can thereby be able to transmit during the duration of the control wrapper frame.

In one embodiment, the transmission characteristic can be information in a protocol version field. In this embodiment, the AP 104 can transmit a frame with a protocol version field set a value greater than zero that can be decodable by a first group of STAs to set the NAV according to the frame while a second group of STAs may not be able to decode the frame and thus may not set their NAV. For example, with respect to FIG. 1, STAs 106a and 106b can be legacy STAs and 106c and 106d can be HEW STAs. The STAs 106a and 106b may not be able to decode a frame with a protocol version field set to a value greater than zero, while the HEW STAs 106c and 106d, on the other hand, can be able to decode this frame and can set their NAV according to the frame. Thus, the STAs 106a and 106b can be able to transmit during the duration of the frame.

In another embodiment, the transmission characteristic can be information in a duration field. In this embodiment, the AP 104 can transmit a frame with a duration field set to an invalid value that can be decodable by a first group of STAs to set the NAV according to the frame while a second group of STAs may not be able to decode the frame and thus may not set their NAV. For example, with respect to FIG. 1, STAs 106a and 106b can be legacy STAs and 106c and 106d can be HEW STAs. The STAs 106a and 106b may not be able to decode a frame with a duration field set to an invalid value, while the HEW STAs 106c and 106d, on the other hand, can be able to decode this frame and can set their NAV according to the frame. Thus, the STAs 106a and 106b can be able to transmit during the duration of the frame.

In another embodiment, the transmission characteristic can be information in a field of an existing frame format. In one embodiment, the AP 104 can transmit a frame with a duration field set to zero. The frame can include a new field, such that the new field can be decodable by a first group of STAs to set the NAV according to the new field of the frame while a second group of STAs may not be able to decode the new field in the frame and thus may not set their NAV. For example, with respect to FIG. 1, STAs 106a and 106b can be legacy STAs and 106c and 106d can be HEW STAs. The STAs 106a and 106b may not be able to decode the new frame, while the HEW STAs 106c and 106d, on the other hand, can be able to decode the new field in the frame and can set their NAV according to the new field. Thus, the STAs 106a and 106b can be able to transmit during the duration of the frame.

In some aspects, an AP 104 or a STA 106 can subsequently transmit a message with a transmission characteristic such that only HEW STAs or a group of HEW STAs can reset the NAV while the legacy STAs do not reset their NAV. In other aspects, an AP 104 can subsequently transmit a message with a transmission characteristic such that only legacy STAs or a group of legacy STAs can reset their NAV while the HEW STAs do not reset their NAV. This would allow the AP 104 to more efficiently allocate access to the medium between the HEW STAs and the legacy STAs.

In one embodiment, the transmission characteristic can be information in a CF-end frame. In this embodiment the AP 104 can transmit a CF-end frame and can set the basic service set identifier (BSSID) to a multicast address to indicate to a first group of STAs to ignore the CF-end frame while a second group of STAs can reset their NAV according to the CF-end frame. For example, with respect to FIG. 1, STAs 106a and 106b can be legacy STAs and 106c and 106d can be HEW STAs. The STAs 106a and 106b can reset their NAV according to the CF-end, while the HEW STAs 106c and 106d, on the other hand, can see the BSSID multicast address as an indication to not reset their NAV.

In another embodiment, the transmission characteristic can be a CF-end frame in a new frame format. In some embodiments, the new CF-end frame format can be only decodable by one group of STAs. In this implementation, with respect to FIG. 1, the STAs 106a and 106b can be operating in a mode according to a legacy IEEE 802.11 standard (i.e. IEEE 802.11b) and STAs 106c and 106d can be operating in a mode according to a IEEE 802.11 high efficiency protocol. In this embodiment, the new CF-end frame may only be decodable by STAs 106c and 106d. The STAs 106c and 106d can then reset their NAV according to the new CF-end frame while the STAs 106a and 106b can be unable to decode the new frame and thus may not reset their NAV.

In one embodiment, the transmission characteristic can be a new frame format with a new type and new subtype, such that the new frame format is not decodable by legacy stations. In this implementation, with respect to FIG. 1, the STAs 106a and 106b can be operating in a mode according to a legacy IEEE 802.11 standard (i.e. IEEE 802.11b) and STAs 106c and 106d can be operating in a mode according to a IEEE 802.11 high efficiency protocol. In one embodiment, the new frame can have a similar structure as an 802.11b (or similar protocol) frame (i.e. a CF-end frame) but STAs 106a and 106b may not be able to decode the new frame and thus may not reset their NAV. The HEW STAs 106c and 106d, on the other hand, can decode the new frame and determine that for this new frame type, they can reset the NAV and thus can access the medium.

In some embodiments, an AP 104 or a STA 106 can reserve the medium for variable period of time. In one aspect, the AP 104 or the STA 106 can send a message instructing the STAs to wait an indicated number of time slots before attempting to access the medium. Each STA receiving the message can perform a backoff procedure with a counter initialized at the indicated time slot value. After each time slot, the STAs can check to see if the medium was busy during the time slot. If the medium was busy, the counter can stay at the previous time slot value. If the medium was idle, the counter can decrease by one, and can continue to wait until the counter reaches zero. Thus, the time period the AP 104 or the STA 106 reserves the medium for can depend on the traffic in the medium and may not be a defined value.

Certain aspects of the present disclosure support allowing APs and STAs to selectively set the NAV of certain subsets of nodes using an RTS/CTS exchange in optimized ways to improve efficiency. Generally, wireless networks that use a regular 802.11 protocol (e.g., 802.11a, 802.11b, 802.11ac, 802.11g, 802.11n, etc.) operate under a carrier sense multiple access (CSMA) mechanism for medium access. According to CSMA, devices sense the medium and only transmit when the medium is sensed to be idle. The use of the CSMA mechanism can create inefficiencies because some APs or STAs located inside or outside of a base service area (BSA) can be able to transmit data without interfering with a transmission made by an AP or STA in the BSA. As the number of active wireless devices continues to grow, the inefficiencies can begin to significantly affect network latency and throughput. The RTS/CTS exchange protocol described herein can allow for devices to operate under a modified mechanism that differentiates between devices that can communicate concurrently with the devices that are exchanging the RTS and CTS frames and devices that cannot communicate concurrently. Accordingly, in the case of apartment buildings or densely-populated public spaces, APs and/or STAs that use the modified RTS/CTS protocol discussed herein can experience reduced latency and increased network throughput even as the number of active wireless devices increases, thereby improving user experience.

FIG. 3 is a diagram of an exemplary wireless communication system 300 for a channel x. In the illustrated embodiment, the wireless communication system 300 includes a plurality of APs (e.g., AP1x, AP2x, AP3x, and AP4), each having a BSA 301-304, and STAs (e.g., STA1x, STA2x, and STA4). In some embodiments the various operations of APs and STAs described herein can be interchanged. For each AP-STA link (e.g., reference link 315) working on channel x, the number of bytes successfully received can be expressed in the following way:

$f\left(\begin{array}{c}\sum _{\underset{\mathrm{CSMA}\mathrm{range}}{\mathrm{ch}xin}}\mathrm{Data}\mathrm{Tx}+\sum _{\underset{\mathrm{CSMA}\mathrm{range}}{\mathrm{ch}x\mathrm{outside}}}\mathrm{Data}\mathrm{Tx}+\\ \sum _{\mathrm{ch}x}\mathrm{ACK}\mathrm{Tx}+\sum _{\mathrm{ch}\ne x}\mathrm{Data}\mathrm{Tx}+\sum _{\mathrm{ch}\ne x}\mathrm{ACK}\mathrm{Tx}\end{array}\right)$

An RTS/CTS exchange can alter the total number of bytes received by effectively the data transmissions (Tx) on the channel x outside the CSMA range and the acknowledgement (ACK) transmissions on channel x to zero. Nodes that send data transmissions (Tx) on the channel x outside the CSMA range and nodes that send acknowledgement (ACK) transmissions on channel x can be considered “jammers” that can cause interference with a given reference link 315 on channel x. Given that RTS/CTS messages silence the nodes receiving the messages, usage of RTS/CTS can decrease system throughput. However, the RTS/CTS exchange can reduce interference and improve reception for a given STA when there are many devices present that can cause interference.

FIG. 4 is a diagram of an exemplary RTS/CTS exchange 400. In conjunction with FIG. 1, in some embodiments, an AP 104 can transmit a RTS frame to a STA 106 and the STA 106 can respond to the RTS frame by sending a CTS frame to the AP 104. An RTS/CTS exchange can be desirable for hidden node mitigation or for clearing the medium when data transmission is not successful for STAs 106. As shown in FIG. 4, the AP1 can transmit an RTS 405 or other message to STA1 with the RTS 405 deferring all STAs and APs within the defer range 401. AP2 is outside the defer range 401, and can be considered a hidden node with respect to the AP1. As shown in FIG. 4, the AP2 can transmit a message 410 to STA2 with its own defer range 402 which can interfere with STA1's reception of the RTS 405 or with its transmission of a responsive CTS frame.

FIGS. 5 and 6 illustrate the effects of the RTS/CTS system. FIG. 5 is a diagram 500 of an exemplary RTS/CTS exchange. FIG. 6 is a time sequence diagram 600 of the RTS/CTS exchange of FIG. 5. In FIGS. 5 and 6, the AP1 transmits to STA1 a RTS fame 601 with a defer range 501. STA1 then responds with a CTS frame 602 with a defer range 502. In conjunction with FIG. 3, the AP2 (hidden node) is then deferred and will remain for the period 610 while the AP1 transmits a data packet 604 to the STA1 and the STA sends an ACK or Block ACK 606. Thus, the RTS 601 and CTS 602 can reserve the medium and prevent interference from any hidden nodes (AP2) during a data transmission 604.

However, if the nodes generate RTS/CTS messages to mitigate the ACK interference effect, the usage of RTS/CTS can be intrusive on the system. For example, N number of jammers can affect a STA (STA1x as shown in FIG. 3). In one aspect, the throughput of the system would equal the sum of the throughputs for all the N jammers (Σ_j=jammers Thj=Thjammer). The throughput of the system with an RTS/CTS exchange would equal the throughput of the non-silenced stations, STA1x as shown (Σ_{j≦non silenced STA}Thj=Throughput of STA1x≡Thsta). If the AP1x or the STA1x are aware of a number M (N>M) such that of the number N jammers, M jammers should be silenced so that the STA1x can transmit data with a throughput Thsta*. In such a system, the system throughput would equal the throughput of STA1x plus the sum of the throughputs of the non-silenced jammers (e.g., Thsta*+Σ_{j=N−M non silenced jammers} Thj>Thjammer>Thsta). An AP 104 or a STA 106 can identify the number of jammers by any conventional means. In some aspects, the AP 104 can perform a scan procedure to identify neighboring basic service sets (BSSs) and the related nodes. In some aspects, the AP 104 can then send a querying message (such as, for example, one or more beacon request messages) to the STA 106 that is the intended recipient of the data (e.g., STA1 is intended recipient of data 604 in FIG. 6). The BSSs heard by the AP 104 and not contained in the querying messages of the STA identify the jammers that should not be silenced (N-M).

FIG. 7 is a diagram of an exemplary RTS/CTS exchange in a wireless communication system 700. For example, as shown in FIG. 7, STA1 and AP1 can use an RTS/CTS exchange to selectively silence certain jammers within their respective defer ranges 701 and 702. In this embodiment, it can be desirable to silence the transmissions at AP2, AP3, AP4, and AP6 and allow the transmission at AP5 so that AP5 can communicate with STA5 while AP1 communicates without STA1 interference from jammer nodes.

In various embodiments, devices such as the AP1 can modulate a transmit power of the RTS in order to decrease the number of exposed nodes and sources that generate ACK interference. For example, the AP1 can gradually increase transmit power of the RTS so as to silence AP6 but not to silence AP5. Systems and methods for such transmit power modulation are described in greater detail below with respect to FIGS. 8 and 9.

FIG. 8 shows a flowchart 800 for an exemplary method of wireless communication that can be employed within the wireless communication system 100 of FIG. 1. The method can be implemented in whole or in part by the devices described herein, such as the wireless device 202 shown in FIG. 2. Although the illustrated method is described herein with reference to the wireless communication system 100 discussed above with respect to FIG. 1, the wireless device 202 discussed above with respect to FIG. 2, and the wireless communication system 700 discussed above with respect to FIG. 7, a person having ordinary skill in the art will appreciate that the illustrated method can be implemented by another device described herein, or any other suitable device. Although the illustrated method is described herein with reference to a particular order, in various embodiments, blocks herein can be performed in a different order, or omitted, and additional blocks can be added.

First, at block 810, the wireless device 202 determines an interference level for a data transmission. For example, the AP1 can determine an interference level for data transmission to the STA1. In various embodiments, the interference level comprises a packet error rate (PER) from the AP1 to the STA1. Thus, in some embodiments, the AP1 can determine PER of the data transmission to the STA1.

Next, at block 820, the wireless device 202 sets a transmission power level, for a message reserving the wireless medium, based on the interference level. For example, the AP1 can set a transmission power level for RTS based on the interference level. As discussed in greater detail herein, in some embodiments, the AP1 can gradually increase the RTS transmission power level until the PER falls below a threshold error rate or value.

Then, at block 830, the wireless device 202 transmits the message reserving the wireless medium at the set transmission power level. For example, the AP1 can transmit the RTS at the set transmission power level. In various embodiments, the message reserving the wireless medium can include one of a request-to-send (RTS) packet and a clear-to-send (CTS) packet.

In various embodiments, the wireless device can identify one or more potentially interfering devices, order the potentially interfering devices based on an estimated transmit power level to reach each potentially interfering device, and set the transmission power level for the message reserving the wireless medium further based on the ordering. For example, the AP1 can identify the AP5 and the AP6 as potentially interfering devices. The AP1 can order the RTS transmission power level estimated to reach the AP5 and AP6, and the AP1 can set the RTS transmission power level to the lowest of the two values.

In various embodiments, setting the transmission power level of the message reserving the wireless medium can include selecting a lowest estimated transmit power level in the ordering and selecting a next highest estimated transmit power level in the ordering when the interference level satisfies a threshold value (for example, is greater than, or is less than, the threshold, depending on the particular interference level or interference metricused). For example, the AP1 can estimate that the AP6 requires a first RTS transmission power level, and the AP5 requires a second RTS transmission power level higher than the first. The AP1 can first transmit an RTS at the first transmission power level and then measure the PER of data transmission to STA1. If the PER is greater than a threshold, the AP1 can next transmit an RTS at the second transmission power level, and so on.

In various embodiments, identifying the one or more potentially interfering devices can include scanning for neighboring basic service sets (BSSs), transmitting a querying message (such as, for example, a beacon request) to an intended recipient (e.g., receiving device) of the data transmission, and identifying devices included in a neighboring BSS, but not visible to or detected by the intended recipient of the data transmission, as potentially interfering devices. For example, the AP1 can scan for neighboring BSSs and can determine that AP5 and AP6 are in range. The AP1 can query the STA1 to determine that only AP2 and AP3 are detected by the STA1. In some embodiments, devices visible to or detected by STA1 comprise devices within the CTS defer range 702 (e.g., AP2, STA2, AP3, STA4, STA6). In some embodiments, devices not visible or detected by STA 1 comprise devices outside the CTS defer range 702 (e.g., AP5, STA5, AP6). Thus, the AP1 can determine that the AP5 and the AP6 are potentially interfering devices which are detected by the AP1 but not visible or detected by STA1 (e.g., within RTS defer range 701 and outside CTS defer range 702).

In various embodiments, estimated transmit power level can be based on a transmit power control (TPC) information element (IE) included in a beacon. For example, the AP1 can receive beacons from the AP5 and the AP6. Each beacon can include an IE including TCP information indicative of a transmit power level to reach each respective AP. In various embodiments, other mechanisms for estimating or determining a transmit power level can be used.

In various embodiments, potentially interfering devices can include devices producing (or capable of producing, or likely to produce) acknowledgement (ACK) interference. For example, as shown in FIG. 7, the AP6 can be a potentially interfering device. In various embodiments herein, transmission power level can be adjusted based on the entirety, or a subset, of actually or potentially interfering devices.

In an embodiment, the method shown in FIG. 8 can be implemented in a wireless device that can include a determining circuit, a setting circuit, and a transmitting circuit. Those skilled in the art will appreciate that a wireless device can have more components than the simplified wireless device described herein. The wireless device described herein includes only those components useful for describing some prominent features of implementations within the scope of the claims.

The determining circuit can be configured to determine the interference level. In an embodiment, the receiving circuit can be configured to implement block 810 of the flowchart 800 (FIG. 8). The determining circuit can include one or more of the receiver 212 (FIG. 2), the transceiver 214 (FIG. 2), the antenna 216 (FIG. 2), the DSP 220 (FIG. 2), the processor 204 (FIG. 2), the signal detector 218 (FIG. 2), and the memory 206 (FIG. 2). In some implementations, means for determining can include the determining circuit.

The setting circuit can be configured to set the transmission power level for the message reserving the wireless medium. In an embodiment, the setting circuit can be configured to implement block 820 of the flowchart 800 (FIG. 8). The setting circuit can include one or more of the transmitter 210 (FIG. 2), the transceiver 214 (FIG. 2), the processor 206 (FIG. 2), the DSP 220 (FIG. 2), and the memory 204 (FIG. 2). In some implementations, means for setting can include the setting circuit.

The transmitting circuit can be configured to transmit the message reserving the wireless medium. In an embodiment, the transmitting circuit can be configured to implement block 830 of the flowchart 800 (FIG. 8). The transmitting circuit can include one or more of the transmitter 210 (FIG. 2), the transceiver 214 (FIG. 2), and the antenna 216 (FIG. 2). In some implementations, means for transmitting can include the transmitting circuit.

FIG. 9 shows a flowchart 900 for an exemplary method of wireless communication that can be employed within the wireless communication system 100 of FIG. 1. The method can be implemented in whole or in part by the devices described herein, such as the wireless device 202 shown in FIG. 2. Although the illustrated method is described herein with reference to the wireless communication system 100 discussed above with respect to FIG. 1, the wireless device 202 discussed above with respect to FIG. 2, and the wireless communication system 700 discussed above with respect to FIG. 7, a person having ordinary skill in the art will appreciate that the illustrated method can be implemented by another device described herein, or any other suitable device. Although the illustrated method is described herein with reference to a particular order, in various embodiments, blocks herein can be performed in a different order, or omitted, and additional blocks can be added.

First, at block 910, the wireless device 202 scans for neighboring basic service sets. For example, the AP1 can scan for neighboring basic service sets by listening for beacons from wireless devices within the neighboring basic service sets. The AP1 can receive beacons from the AP5 and the AP6. In some embodiments, the beacons can include IEs indicating TCP information. Thus, the AP1 can estimate a transmission power level to reach each of the AP5 and the AP6.

Next, at block 920, the wireless device 202 transmits a querying message to an intended recipient of data transmission. For example, the AP1 can transmit a beacon request to the STA1. The STA1 can receive beacons from the AP1, the AP2, and the AP3. Thus, the STA1 can identify one or more of the AP1, the AP2, and the AP3 to the AP1. The wireless device 202 can receive a query response from the intended data recipient. The query response may include a list of devices from which it has received beacons from (e.g., detected devices).

Then, at block 930, the wireless device 202 identifies one or more devices included in a neighboring BSS, but not visible to the intended data recipient. For example, the AP1 can subtract the set of APs visible to or detected by the STA1 from the set of APs visible to or detected by the AP1. Thus, the AP1 can identify the AP5 and the AP6 as potential jammers (e.g., devices within RTS defer range 701 and outside CTS defer range 702).

Subsequently, at block 940, the wireless device 202 orders the identified devices based on an estimated transmit power level to reach each device. For example, the AP1 can determine transmit power levels to reach each of AP5 and AP6 (for example, based on their beacons as discussed above). AP6 can be associated with a first transmit power level and the AP5 can be associated with a second transmit power level, higher than the first level. Thus, the transmit power level of AP6 can be placed first in a vector and the transmit power level of AP5 can be placed second in the vector. Additional APs not shown can be similarly ordered.

Thereafter, at block 950, the wireless device 202 sets the transmission power level for an RTS to the lowest estimated transmit power level. For example, the AP1 can set RTS transmission power level to the first transmit power level associated with the AP6.

Next, at block 960, the wireless device 202 performs RTS/CTS and/or data transmission. For example, the AP1 can transmit the RTS at the first transmit power level, the STA1 can transmit the CTS, and the AP1 can transmit data to the STA1 as discussed above with respect to FIG. 6.

Then, at block 970, the wireless device 202 can measure the PER of the data transmission. For example, the AP1 can measure the PER of the data transmission to the STA1, and can compare the measured PER to a threshold value. In various embodiments, the threshold can be preset or dynamically determined. If the PER is less than or equal to the threshold, the wireless device 202 can proceed to maintain the currently set RTS transmission power level at block 980.

Alternatively, if the PER is greater than the threshold, the wireless device 202 can proceed to block 990. At block 990, the wireless device 202 sets RTS transmission power level to the next highest estimated transmit power in the ordered vector. For example, the AP1 can set the RTS transmit power level to the second transmit power associated with the AP5. Where the wireless system includes additional APs not shown, blocks 960-990 can be repeated in a similar manner for each new transmission power level. Accordingly, the wireless device 202 can modulate RTS transmission power level to increase likelihood of excluding ACK interference (e.g., AP6) while decreasing the likelihood of silencing exposed terminals (e.g., AP5).

A person/one having ordinary skill in the art would understand that information and signals can be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that can be referenced throughout the above description can be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

Various modifications to the implementations described in this disclosure can be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other implementations without departing from the spirit or scope of this disclosure. Thus, the disclosure is not intended to be limited to the implementations shown herein, but is to be accorded the widest scope consistent with the claims, the principles and the novel features disclosed herein. The word “exemplary” is used exclusively herein to mean “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other implementations.

Certain features that are described in this specification in the context of separate implementations also can be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation also can be implemented in multiple implementations separately or in any suitable sub-combination. Moreover, although features can be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination can be directed to a sub-combination or variation of a sub-combination.

As used herein, a phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover: a, b, c, a-b, a-c, b-c, and a-b-c.

The various operations of methods described above can be performed by any suitable means capable of performing the operations, such as various hardware and/or software component(s), circuits, and/or module(s). Generally, any operations illustrated in the Figures can be performed by corresponding functional means capable of performing the operations.

The various illustrative logical blocks, modules and circuits described in connection with the present disclosure can be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array signal (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components or any combination thereof designed to perform the functions described herein. A general purpose processor can be a microprocessor, but in the alternative, the processor can be any commercially available processor, controller, microcontroller or state machine. A processor can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

In one or more aspects, the functions described can be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions can be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A storage media can be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a web site, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Thus, in some aspects computer readable medium can comprise non-transitory computer readable medium (e.g., tangible media). In addition, in some aspects computer readable medium can comprise transitory computer readable medium (e.g., a signal). Combinations of the above should also be included within the scope of computer-readable media.

The methods disclosed herein comprise one or more steps or actions for achieving the described method. The method steps and/or actions can be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and/or use of specific steps and/or actions can be modified without departing from the scope of the claims.

Further, it should be appreciated that modules and/or other appropriate means for performing the methods and techniques described herein can be downloaded and/or otherwise obtained by a user terminal and/or base station as applicable. For example, such a device can be coupled to a server to facilitate the transfer of means for performing the methods described herein. Alternatively, various methods described herein can be provided via storage means (e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or floppy disk, etc.), such that a user terminal and/or base station can obtain the various methods upon coupling or providing the storage means to the device. Moreover, any other suitable technique for providing the methods and techniques described herein to a device can be utilized.

While the foregoing is directed to aspects of the present disclosure, other and further aspects of the disclosure can be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

1. A method of wireless communication over a wireless communication medium comprising:

determining a level of interference for a data transmission from a transmitting device to an intended receiving device;

setting a transmission power level for transmitting a message based on the interference level, the message comprising one of a request-to-send (RTS) packet and a clear-to-send (CTS) packet; and

transmitting the message at the set transmission power level.

2. The method of claim 1, wherein the transmitting device and the receiving device each comprises one of an access point and a station.

3. The method of claim 1, wherein the level of interference is based on at least a packet error rate (PER) of the data transmission from the transmitting device to the intended receiving device.

4. The method of claim 1, further comprising:

identifying one or more potentially interfering devices detected by the transmitting device;

ordering the potentially interfering devices based on an estimated transmit power level from the transmitting device to reach each of the potentially interfering devices, wherein the ordering identifies from a lowest estimated transmit power to a highest estimated transmit power level; and

setting the transmission power level for transmitting the message based further on the ordering of the estimated transmit power levels for the potentially interfering devices.

5. The method of claim 4, wherein the setting of the transmission power level of the message comprises:

selecting a smallest estimated power level from the lowest to the highest estimated power levels in the ordering such that a new interference level based on the data transmission at the selected smallest transmit power level satisfies a threshold value.

6. The method of claim 4, wherein the setting of the transmission power level of the message comprises:

selecting a smallest estimated power level from the lowest to the highest estimated power levels in the ordering for a first transmission of the message from the transmitting device to the receiving device;

transmitting the first transmission at the selected smallest transmit power level;

determining an interference level for the first transmission;

selecting a next highest estimated power level from the lowest to the highest estimated power levels for a second transmission of the message if the interference level for the first transmission is greater than the threshold;

transmitting the second transmission at the selected next highest estimated transmit power level;

determining an interference level for the second transmission;

selecting a next highest estimated power level from the lowest to the highest estimated power levels for a third transmission of the message if the interference level of the second transmission is greater than the threshold; and

setting the transmission power level of the message to selected estimated power level if an interference level of one of the data transmissions is less than the threshold.

7. The method of claim 4, wherein identifying the one or more potentially interfering devices comprises:

scanning for neighboring basic service sets (BSSs);

transmitting a querying message from the transmitting device to the intended receiving device of the data transmission; and

identifying devices included in a neighboring BSS from the scanned list of neighboring BSSs, but not detected by the intended receiving device of the data transmission, as potentially interfering devices.

8. The method of claim 6, wherein scanning for neighboring BSSs comprises receiving beacons from potentially interfering devices, wherein the estimated transmit power level is based on a transmit power control (TPC) information element (IE) included in the received beacons.

9. The method of claim 6, further comprising receiving a query response message from the intended receiving device identifying a list of devices detected by the intended receiving device as potentially interfering devices for the data transmission from the transmitting device to the intended receiving device.

10. The method of claim 8, wherein identifying devices included in a neighboring BSS from the scanned list of neighboring BSSs, but not detected by the intended receiving device of the data transmission, as potentially interfering devices comprises comparing the potentially interfering devices detected by the transmitting device with the potentially interfering devices detected by the intended receiving device.

11. The method of claim 4, wherein the estimated transmit power level is based on a transmit power control (TPC) information element (IE) included in a beacon received from potentially interfering devices.

12. The method of claim 4, wherein identifying potentially interfering devices detected by the transmitting device comprises identifying devices transmitting acknowledgement (ACK) messages that may potentially interfere with the data transmission from the transmitting device to the intended receiving device.

13. An apparatus configured to perform wireless communication over a wireless communication medium comprising:

a processor configured to: determine a level of interference for a data transmission to an intended receiving device; and set a transmission power level for transmitting a message based on the interference level, the message comprising one of a request-to-send (RTS) packet and a clear-to-send (CTS) packet; and

a transmitter configured to transmit the message at the set transmission power level.

14. The apparatus of claim 13, wherein the wherein the receiving device comprises one of an access point and a station.

15. The apparatus of claim 13, wherein the level of interference is based on at least a packet error rate (PER) of the data transmission to the intended receiving device.

16. The apparatus of claim 13, wherein the processor is further configured to:

identify one or more potentially interfering devices detected by the processor;

order the potentially interfering devices based on an estimated transmit power level from the transmitting device to reach each of the potentially interfering devices, wherein the ordering identifies from a lowest estimated transmit power to a highest estimated transmit power level; and

set the transmission power level for transmitting the message based further on the ordering of the estimated transmit power levels for the potentially interfering devices.

17. The apparatus of claim 16, wherein the processor is further configured to select a smallest estimated power level from the lowest to the highest estimated power levels in the ordering such that a new interference level based on the data transmission at the selected smallest transmit power level satisfies a threshold value.

18. The apparatus of claim 16, further comprising a receiver configured to scan for neighboring basic service sets (BSSs), wherein:

the transmitter is further configured to transmit a querying message to the intended receiving device of the data transmission; and

the processor is further configured to identify devices included in a neighboring BSS from the scanned list of neighboring BSSs, but not detected by the intended receiving device of the data transmission, as potentially interfering devices.

19. The apparatus of claim 16, further comprising a receiver configured to receive beacons from the potentially interfering devices, wherein the estimated transmit power level is based on a transmit power control (TPC) information element (IE) included in the beacons.

20. The apparatus of claim 16, wherein the processor is further configured to identify devices producing acknowledgement (ACK) interference.

21. An apparatus for wireless communication over a wireless communication medium comprising:

means for determining a level of interference for a data transmission to an intended receiving device;

means for setting a transmission power level for transmitting a message based on the interference level, the message comprising one of a request-to-send (RTS) packet and a clear-to-send (CTS) packet; and

means for transmitting the message at the set transmission power level.

22. The apparatus of claim 21, wherein the level of interference is based on at least a packet error rate (PER) of the data transmission from the transmitting device to the intended receiving device.

23. The apparatus of claim 21, further comprising:

means for identifying one or more potentially interfering devices;

means for ordering the potentially interfering devices based on an estimated transmit power level from the transmitting means to reach each of the potentially interfering devices, wherein the ordering means identifies from a lowest estimated transmit power to a highest estimated transmit power level; and

means for setting the transmission power level for transmitting the message based further on the ordering of the estimated transmit power levels for the potentially interfering devices.

24. The apparatus of claim 23, wherein means for setting the transmission power of the message reserving the wireless medium comprises means for selecting a smallest estimated power level from the lowest to the highest estimated power levels in the ordering such that a new interference level based on the selected smallest transmit power level satisfies a threshold value.

25. The apparatus of claim 23, wherein means for identifying the one or more potentially interfering devices comprises:

means for scanning for neighboring basic service sets (BSSs);

transmitting a querying message to the intended receiving device of the data transmission; and

means for identifying devices included in a neighboring BSS from the scanned list of neighboring BSSs, but not detected by the intended receiving device of the data transmission, as potentially interfering devices.

26. The apparatus of claim 23, wherein means for identifying potentially interfering devices comprises identifying devices producing acknowledgement (ACK) interference.

27. A non-transitory computer-readable medium comprising code that, when executed, causes an apparatus to:

determine a level of interference for a data transmission from a transmitting device to an intended receiving device;

set a transmission power level for transmitting a message based on the interference level, the message comprising one of a request-to-send (RTS) packet and a clear-to-send (CTS) packet; and

transmit the message the message at the set transmission power level.

28. The medium of claim 27, further comprising code that, when executed, causes the apparatus to:

identify one or more potentially interfering devices;

order the potentially interfering devices based on an estimated transmit power level from the transmitting device to reach each of the potentially interfering devices, wherein the ordering identifies from a lowest estimated transmit power to a highest estimated transmit power level; and

set the transmission power level for transmitting the message based further on the ordering of the estimated transmit power levels for the potentially interfering devices.

29. The medium of claim 28, wherein setting the transmission power of the message reserving the wireless medium comprises:

selecting a smallest estimated power level from the lowest to the highest estimated power levels in the ordering such that a new interference level based on the selected smallest transmit power level satisfies a threshold value.

30. The medium of claim 28, wherein identifying the one or more potentially interfering devices comprises:

scanning for neighboring basic service sets (BSSs);

transmitting a querying message from the transmitting device to the intended receiving device of the data transmission; and

identifying devices included in a neighboring BSS from the scanned list of neighboring BSSs, but not detected by the intended receiving device of the data transmission, as potentially interfering devices.