Abstract: The present invention provides for a reliable communication over radio networks co-existing in the same frequency band. According to the present invention, a transceiver operating according to another transmission scheme may transmit a frame in the IEEE 802.11 format. This frame may comprise an error. Upon receipt of this frame by an IEEE 802.11 station, this station may defer from channel access for a period of time.

Abstract: Disclosed is a method and system for dynamically selecting a communication channel between an access point (AP) and a plurality of stations (STAs) in an IEEE 802.11 wireless local area network (WLAN). The method includes the steps of: determining whether a new channel between the AP and STAs within a particular basic service set (BSS) is needed; requesting a channel signal quality measure to some of the plurality of stations by the AP; reporting a channel signal quality report back to the AP based on a received signal strength indication (RSSI) and a packet error rate (PER) of all channels detected by the stations within the BSS; selecting a new channel based on the channel quality report for use in communication between the AP and the plurality of stations.

Abstract: A medium access control (MAC) protocol is provided for avoiding collisions from stations (STAs) comprising two or more IEEE 802.11 basic service sets (BSSs) collocated and operating in the same channel during contention free periods (CFPs). The MAC protocol includes hardware/software for utilizing ready-to-send (RTS)/clear-to-send(CTS) exchange during CFPs to avoid potential collision from STAs in overlapping BSSs and hardware/software for providing overlapping network allocation vectors (ONAV) in addition to a network allocation vector (NAV), the ONAV included to facilitate the effectiveness of the RTS/CTS during CFPs.

Abstract: Disclosed is a method and system for dynamically selecting a communication channel between an access point (AP) and a plurality of stations (STAs) in an IEEE 802.11 wireless local area network (WLAN). The method includes the steps of: determining whether a new channel between the AP and STAs within a particular basic service set (BSS) is needed; requesting a channel signal quality measure to some of the plurality of stations by the AP; reporting a channel signal quality report back to the AP based on a received signal strength indication (RSSI) and a packet error rate (PER) of all channels detected by the stations within the BSS; selecting a new channel based on the channel quality report for use in communication between the AP and the plurality of stations.

Abstract: A method and apparatus for determining the transmission power level between a plurality of stations located within the coverage area of a basic service set (BSS) in a wireless local area network (WLAN). The receiving station measures a received signal power from the transmitting station, then the path loss estimation is computed based on the difference between the received signal power and the transmit power level extracted from the incoming signal. The computed path loss is updated according predetermined criteria. Based on the updated path loss information, the transmit power level and/or the transmission rate of a receiving station is adjusted.

Abstract: A system and method for providing concurrent transmission in a wireless Local Area Network (WLAN) are provided. The WLAN includes a plurality of stations for transmitting information via an assigned TDM time slot, and an access point in communication with the stations for monitoring access control and providing time allocation to allow data exchange between multiples pairs of stations, without the intervention of the access point. For establishing concurrent transmission, the access point periodically broadcasts a signal message to the stations over a wireless communication channel to determine pairs of stations that are hidden from each other based on the interference power level reported by each station.

Abstract: A channel quieting/measurement request element is provided for use in a wireless local area network. The unified element of the invention integrates a dual capability for performing channel quieting and for making measurement requests of one or more stations in the network. According to another aspect of the invention, a conventional channel quieting element is modified to include provisions for defining an offset time and an offset duration interval for performing channel quieting.

Abstract: In this document, we proposed a hybrid MAC protocol that can utilize the precious wireless link bandwidth efficiently in the environment of a partially connected wireless network topology and VBR connections running in the network.

Abstract: The present invention is a method and system for reducing and potentially eliminating the number of packets dropped during 802.11 handoff by an old access point (AP) to a new AP in a wireless local area network (WLAN) which thereby also reduces the impact of retransmission on network throughput. With the present invention, once a mobile station has successfully re-associated with a new AP, the new AP can fetch those packets which arrived at the old AP during handoff and forward them to the mobile station. The method and system of the present invention thus reduces both total packet drop and retransmission impact on network throughput by enabling direct recovery of packets received during handoff by the old AP from the old AP.

Abstract: A method and system for determining the transmission rate between a plurality of stations in a wireless local area network (WLAN) are provided. Each mobile station evaluates the current link condition based on the Received Signal Strength (RSS) from received frames and adjusts a new transmission rate according to predetermined criteria, which is updated based on whether the transmission of subsequent signals is successful.

Abstract: The present invention relates to a method for performing fast channel switching in a wireless local area network (WLAN). The method generally includes the steps of: determining that the wireless medium has been idle during a PCF interframe space (PIFS) period, transmitting a first management frame during a slot time following the PIFS period; wherein the transmission at said slot time substantially guarantees priority access said wireless medium; and performing fast channel switching in the network in accordance with directives contained within the management frame. Fast channel switching as defined herein includes one of quieting the current channel and/or switching from a current channel of operation to a new channel of operation. The method overcomes the latencies associated with contention based services, such as the DCF service.

Abstract: This invention discloses a set of internal signaling (i.e., management primitives) to support a clock-synchronization protocol for wirelessly synchronizing clock registers of wired or wireless nodes via a wireless local area network (i.e., 802.11 network). The clock synchronization is performed between two higher-layer protocol entities residing within two different wireless stations (STAs).

Abstract: A clock synchronization method and apparatus is disclosed for use in a communication system including a plurality of wireless nodes communicatively coupled via a wireless network, each of the plurality of wireless nodes having a local time base, and one of the plurality of wireless nodes being designated as a master node having a master time base which serves as a master clock against which the local time bases are synchronized. The clock synchronization method includes the steps of periodically transmitting synchronization frames to the plurality of non-master nodes so as to adjust the slave clocks associated with the respective non-master nodes. The synchronization frames are distributed from the master node at near-periodic intervals and includes a cycle time value that corresponds to the end of the previously transmitted synchronization frame. The slave clocks (i.e.

Abstract: A local-area network is provided where OFDM stations and DSSS/CCK-only stations coexist. A beacon signal having a contention-free-period (CFP) is transmitted from an access point to the plurality of said stations. The OFDM-modulated data is transmitted to the plurality of stations before the CFP ends, and after the CFP period ends, the DSSS/CCK-modulated data is transmitted, thereby preventing collisions between the stations.

Abstract: The present invention relates to a method and system for enhancing the performance of the Forward-Error-Correction (FEC) scheme in a wireless local area network (WLAN). When a transmission error occurs more than a predetermined number of times using a first modulation scheme, the data transmission rate of the first modulation scheme is compared to a predetermined data rate and, if greater, the retransmission of error data is performed using a second modulation scheme.

Abstract: A local area network is provided where an OFDM station and DSSS/CCK station coexist. During a contention-free period both stations operate under the point coordination function rules as defined in the IEEE 802.11 specification. Both stations transmit data when polled by the access point. The contention-free period comprises a sub-contention period during which only the OFDM station communicate. During the sub-contention period the OFDM station operates under the distributed coordination function while the DSSS/CCK station waits to be polled by the access point before starting to communicate.

Abstract: A local area network is provided where OFDM stations and DSSS/CCK only stations coexist. Before transmitting, an OFDM station learns of the modulation capability of an intended receiving station. If the receiving station is only capable of DSSS/CCK modulation then the OFDM station transmits DSSS/CCK modulated data. If the receiving station is capable of OFDM modulation, then the OFDM station transmits OFDM modulated data thereby enabling efficient bandwidth usage.

Abstract: The present invention is related to a medium access control (MAC) protocol for avoiding collisions among ESTAs when two or more overlapping basic service sets (OBSSs) co-exist and operate in the same channel. To achieve this, each mobile station operating under HCF maintains a first counter known as Network Allocation Vector (NAV) and a second counter known as Overlapping Network Allocation Vector (ONAV), which is updated within a mobile station by frames coming from OBSSs, during the Contention Free Period (CFP) or during a Contention Free Burst (CFB) granted by a polling frame. The mobile station uses the NAV to update only to the medium occupancy in its own BSS to ensure that the mobile station will not interfere with the transmissions in its own QBSS, while the ONAV is used to avoid collisions with the mobile stations from the OBSS.

Abstract: An apparatus and method for improving the signal reception of a digital wireless receiver comprises a processing circuit for processing the preamble information of incoming signals, wherein a first predetermined portion of the preamble information is applied to a first antenna and a second predetermined portion of the preamble information is applied to a second antenna to produce a plurality of processed signals, such that the plurality of processed signals is compared to a predefined preamble sequence to obtain a mean-square error (MSE) for the respective antenna. Then, one of the first and second antennas with a lower MSE is selected to receive and process the incoming signals.

Abstract: A method and system for combining signals in a receiver are provided. If the current packet is determined to be the retransmitted packet according to predetermined criteria, The retransmitted packet and the previously stored packet in error with the same packet number are combined using a maximum ratio combining method according to the signal-to-noise-ratio (SNR) calculated from the preamble of each packet. With this type of diversity combining, a reliable data packet transmission in a shorter time period can be obtained while increasing the SNR and reducing the throughput time in multipath channel.