Abstract: A method of providing feedback on channel observations to a transmitter includes observing a channel at a receiver based on received signals from the transmitter and determining whether a packet error rate (PER) is rising based on the observing. The receiver determines whether a rising PER is caused by channel noise or interference, and transmits a message to the transmitter indicating the cause of the rising PER. The cause may be encoded in reserved bits of a block acknowledgement (BA) frame or an Acknowledge (ACK) frame, or in a modulation coding scheme (MCS) used to transmit the message. The cause may be detected in response to SNR/RSSI level of received signals, or a number of receiver restarts. The transmitter may change the transmit rate adaptation algorithm to use a lower MCS if channel noise causes the rising PER, and a higher MCS if interference causes the rising PER.

Abstract: Systems and methods are disclosed for coordinating operation on multiple frequency bands between two or more multiple concurrent band (MCB) devices. The band switch protocols may include sending information on a second band after a communications link has been established on a first band. The receiving device may treat the transmission of the frame on the new band as a message to switch bands, such that the transmitting and receiving devices may conduct subsequent communications on the new band. Further, the band switch protocols allow for seamless operation over the band switch event. As a result, a frequency band having desired performance characteristics may be selected dynamically.

Abstract: A wireless device is configured to switch data rates to account for temporary channel conditions or device configuration errors. Pre-selected data rates, more likely to achieve maximum goodput, are stored in a data rate table. The data rate table contains candidate data rates for each pre-selected data rate in the data rate table. When probe transmissions using the preselected data rates fail, dynamic rate probing is utilized to determine a possible cause and extent of the problem. The dynamic rate probing scheme transmits probe transmissions using the candidate data rates and tracks success or failure of these probe transmissions. An analysis of the probe transmissions is used to indicate a possible cause and/or extent of the problematic condition and to determine whether there is a need to reconfigure the data rates in the data rate table.

Abstract: Systems and methods are disclosed for generating a statistical profile of a MIMO channel. Packets of information may be transmitted over an interval of time to a plurality of stations using a plurality of MIMO modes. Each packet may be binned and a goodput value corresponding to the bin, the station and the MIMO mode may be determined stored.

Abstract: Systems and methods are disclosed for scheduling SU and MU traffic in a MIMO communications system. Net goodput may be estimated for a station using a plurality of MIMO modes and a transmission to the station may be scheduled using one of the MIMO modes based, at least in part, on the estimated net goodput. Estimating net goodput may include determining a number of bits that may be successfully transmitted to the station using the MIMO mode divided by a time required to transmit the number of bits plus the sounding time. Further, the number of bits that may be successfully transmitted to the station may be based on the number of packets that may be delivered over the upcoming sounding interval and statistically determined goodput for each MIMO mode.

Abstract: Systems and methods are disclosed for optimizing the sounding interval in a MIMO communications system. Following a channel sounding protocol, net throughput may be estimated over time. The sounding interval may correspond to the period of time between the end of the sounding protocol and a time when the estimated net throughput is maximized. Estimating net throughput may involve estimating the number of bits that may be successfully transmitted divided by the time required to transmit. The number of bits that may be successfully transmitted may be estimated from a statistical channel profile including goodput.

Abstract: An access point can include an array of antennas and a smart antenna selector. The smart antenna selector is configured to select a subset of antennas from the antenna array for use in multi-user multiple-input multiple-output (MU MIMO) data transmissions. Stations that are communicatively coupled to the access point can be selected for inclusion in a multi-user group based, at least in part, on performance measurements of the stations. Performance measurements are determined directly and indirectly from data transmissions sent in response to sounding packets. Antennas for use in MU MIMO data transmissions are selected for the antenna array based, at least in part, on previous antenna selections used for single user data transmissions.

Abstract: One innovation includes an apparatus, for wirelessly communicating with a communication system via a first wireless channel and a second wireless channel, including a memory unit that is configured to store a first data packet and a second data packet, the first data packet and the second data packet have consecutive sequence numbers. The apparatus further includes a processor configured to retrieve the first data packet and the second data packet from the memory unit, a transceiver that is configured to transmit the first data packet to the communication system via the first channel, to receive a first acknowledgement from the communication system and to transmit the second data packet to the communication system via the second channel after the processor detects that the first acknowledgement comprises a positive acknowledgement of the first reception information.

Abstract: MAC layer frame aggregation and block acknowledgement are used in some WLAN technologies to improve efficiency of a communications channel by reducing PHY layer overhead. A frame aggregation window size defines how many MAC protocol data units (MPDUs) are included in an aggregated MPDU (AMPDU) frame. The frame aggregation window for a subsequent AMPDU frame is typically dependent upon the characteristics of the block acknowledgement—such as the number of non-acknowledged (NAK) MPDUs or the position of a hole in the previous AMPDU frame. A small frame aggregation window size may impact throughput especially at higher transmission rates. In this disclosure a transmission rate may be determined based, at least in part, on a projected frame aggregation window size resulting from a block acknowledgement. The frame aggregation feedback (e.g. block acknowledgement) may be used by a rate control module to determine a transmission rate that optimizes frame aggregation efficiency.

Abstract: Various aspects of the disclosure described herein provide for optimizing rate control during a selection of a communications profile from a set of communications profiles by taking into account effective frame aggregation size as a function of packet error rate (PER). An expected throughput may also be determined for each communications profile and updated after each transmission so that a communications profile having the highest expected throughput may be chosen for a particular frame transmission.

Abstract: Systems and methods for carrier sense multiple access (CSMA) protocols for power line communications (PLC) are described. In some embodiments, a method may include performing a virtual carrier sensing operation and, in response to the virtual carrier sensing operation indicating that a communication channel is idle, calculating a contention window. The method may also include performing a physical carrier sensing operation subsequent to the virtual carrier sensing operation, the physical carrier sensing operation based, at least in part, upon the contention window. In response to the physical carrier sensing operation indicating that the communication channel is idle, the method may then include transmitting data over the channel. In other embodiments, another method may include determining that a data transmission is a unicast transmission and that an acknowledgement message has not been received.

Abstract: A method of providing aggregated MAC protocol data unit (AMPDU) duration control in a wireless communication device includes setting an AMPDU duration. Pass/fail statistics are collected for each MPDU of an AMPDU in a time window, W. A packet error rate (PER) difference is calculated between first and last sets of MPDUs for each AMPDU in the window. An average PER difference is calculated across all AMPDUs in the window. When the average PER difference is greater than a first threshold, then the AMPDU duration is decreased. When the difference is less than a second threshold, then the AMPDU duration is increased. When the difference is within the first and the second thresholds, then the method returns to the step of collecting for a next time window. The AMPDU duration can also be adjusted based on detected Doppler and line-of-sight transmissions.

Abstract: A method of performing dual-mode rate control for an access point in a wireless communication system includes a single-user mode of operation and a multi-user mode of operation. In the single-user mode, a basic rate for a station is determined based on channel conditions. In the multi-user mode, a rate for a plurality of stations is determined using tracking. The tracking includes performing a sounding for the plurality of stations. An initial multi-user current rate is then set equal to a function of a number of users and the basic rate. A transmission is sent to the plurality of stations using the current rate. A packet error rate (PER) is detected during transmission to the plurality of stations. The current rate is adjusted based on the PER. After rate adjustment, either sounding is triggered or the method returns to sending a transmission using the current rate.

Abstract: A method of performing transmission from an access point (AP) in a wireless communication system provides transmission setting adjustment after sounding. In this method, stations associated with the AP and having transmission data can be identified. Transmission to those stations can be performed using a predetermined transmission setting. For a first transmission after a sounding, the predetermined transmission setting can be boosted. For any transmission other than the first transmission after the sounding, a current or adjusted transmission setting can be used based on a detected PER during transmission. An adjusted transmission setting can be an MCS rate, a user-level (SU-BF, 2U-MIMO, or 3U-MIMO), or an aggregated MAC protocol data unit (AMPDU) aggregation level. A single transmission setting or a combination of settings can be used. The method can be used with any transmission setting(s), including those mapped from the Signal to Interference and Noise Ratio (SINR).

Abstract: A method of providing rate adaptation in a multi-user wireless communication system including single-user beamforming (SU-BF) and multi-user multiple-input multiple-output (MU-MIMO) is described. In this method, a master rate, which is a modulation and coding scheme (MCS) for the SU-BF, is determined. An MCS for each transmit mode is derived from the master rate using a rate mapping. Using the results from the mapping, the master rate, instead of the MCS for each transmit mode, is tracked. In one embodiment, a mapping calibration is periodically performed.

Abstract: Various aspects of apparatus for accessing a network through a wireless access point and methods of power savings for such apparatus include operating in a sleep state, and scheduling one or more sleep state intervals for operating in the sleep state during a time period, wherein the scheduled one or more sleep state intervals are based on one or more wireless transmission parameters.

Abstract: Various aspects of apparatus for accessing a network through a wireless access point and methods of power savings for such apparatus include scheduling a sleep state interval, entering a sleep state at the beginning of the scheduled sleep interval, and buffering data during the sleep state for transmission following the sleep state.

Abstract: Various aspects of apparatus for accessing a network through a wireless access point and methods of power savings for such apparatus include autonomously alternating between a listen state and the sleep state during a time period in which no data is detected from the remote apparatus, and progressively increase the sleep state interval during the time period for at least a portion of the time period.

Abstract: A method of providing multicast rate control in a wireless communication device can include transmitting data frames to a plurality of stations in a multicast group with a first data rate. Acknowledgements (ACKs) can then be requested from a first subset of the plurality of stations. Frame losses can be determined using the ACKs from the first subset. A second data rate can be determined based on the frame losses with the first subset. A second subset of the plurality of stations can be selected based on the frame losses with the first subset. Data frames can be transmitted to the plurality of stations with the second data rate. Notably, ACKs only from the second subset of the plurality of stations are requested. Frame losses for the second subset can be determined using those ACKs. A current data rate can be adjusted based on the frame losses for the subset and at least one predetermined threshold. Data frames can be transmitted to the plurality of stations using the adjusted data rate.

Abstract: An apparatus includes a generator including a control module that is operably coupled to a power module. The power module is configured to produce an electronic signal to be received by an ultrasonic energy delivery assembly. The ultrasonic energy delivery assembly is characterized by a natural frequency, and the electronic signal is characterized by a frequency. The control module is configured to send a control signal to the power module to randomly vary the frequency of the electronic signal within a range defined at least in part by the natural frequency.