Abstract: Techniques for performing acquisition of packets are described. First detection values may be determined based on a first plurality of samples, e.g., by performing delay-multiply-integrate on the samples. Power values may be determined based on the first plurality of samples, e.g., by performing multiply-integrate on the samples. The first detection values may be averaged to obtain average detection values. The power values may also be averaged to obtain average power values. Whether a packet is presence may be determined based on the average detection values and the average power values. Second detection values may be determined based on a second plurality of samples. The start or the packet may be determined based on the first and second detection values. A third detection value may be determined based on a third plurality of samples. Frequency error of the packet may be estimated based on the first and third detection values.

Abstract: A transmitting entity performs spatial processing on data symbols for each subband with an eigenmode matrix, a steering matrix, or an identity matrix to obtain spatially processed symbols for the subband. The data symbols may be sent on orthogonal spatial channels with the eigenmode matrix, on different spatial channels with the steering matrix, or from different transmit antennas with the identity matrix. The transmitting entity further performs beamforming on the spatially processed symbols, in the frequency domain or time domain, prior to transmission from the multiple transmit antennas. A receiving entity performs the complementary processing to recover the data symbols sent by the transmitting entity. The receiving entity may derive a spatial filter matrix for each subband based on a MIMO channel response matrix for that subband and perform receiver spatial processing for the subband with the spatial filter matrix.

Abstract: A transmitting entity performs spatial processing on data symbols for each subband with an eigenmode matrix, a steering matrix, or an identity matrix to obtain spatially processed symbols for the subband. The data symbols may be sent on orthogonal spatial channels with the eigenmode matrix, on different spatial channels with the steering matrix, or from different transmit antennas with the identity matrix. The transmitting entity further performs beamforming on the spatially processed symbols, in the frequency domain or time domain, prior to transmission from the multiple transmit antennas. A receiving entity performs the complementary processing to recover the data symbols sent by the transmitting entity. The receiving entity may derive a spatial filter matrix for each subband based on a MIMO channel response matrix for that subband and perform receiver spatial processing for the subband with the spatial filter matrix.

Abstract: Spatial spreading is performed in a multi-antenna system to randomize an “effective” channel observed by a receiving entity for each transmitted data symbol block. For a MIMO system, at a transmitting entity, data is processed (e.g., encoded, interleaved, and modulated) to obtain ND data symbol blocks to be transmitted in NM transmission spans, where ND?1 and NM>1. The ND blocks are partitioned into NM data symbol subblocks, one subblock for each transmission span. A steering matrix is selected (e.g., in a deterministic or pseudo-random manner from among a set of L steering matrices, where L>1) for each subblock. Each data symbol subblock is spatially processed with the steering matrix selected for that subblock to obtain transmit symbols, which are further processed and transmitted via NT transmit antennas in one transmission span. The ND data symbol blocks are thus spatially processed with NM steering matrices and observe an ensemble of channels.

Abstract: A multiple-access MIMO WLAN system that employs MIMO, OFDM, and TDD. The system (1) uses a channel structure with a number of configurable transport channels, (2) supports multiple rates and transmission modes, which are configurable based on channel conditions and user terminal capabilities, (3) employs a pilot structure with several types of pilot (e.g., beacon, MIMO, steered reference, and carrier pilots) for different functions, (4) implements rate, timing, and power control loops for proper system operation, and (5) employs random access for system access by the user terminals, fast acknowledgment, and quick resource assignments. Calibration may be performed to account for differences in the frequency responses of transmit/receive chains at the access point and user terminals. The spatial processing may then be simplified by taking advantage of the reciprocal nature of the downlink and uplink and the calibration.

Abstract: Mesh Network Access Points (APs) points, including gateways and routers, are deployed over a geographic area. The APs monitor the communication channel for other carriers and transmit accordingly. The APs selectively co-transmit when other carriers are sensed, if the efficiency of the mesh network will improve. APs select a transmission rate based on observed carrier-to-interference ratios. APs use directional antennas to increase carrier-to-interference ratios and spectral efficiency. AP transmit schedules are adaptable and adjusted according to observed carrier-to-interference measurements.

Abstract: Techniques for MAC processing for efficient use of high throughput systems that is backward compatible with various types of legacy systems are disclosed. In one aspect a first signal is transmitted according to a legacy transmission format to reserve a portion of a shared medium, and communication according to a second transmission format transpires during the reserved portion. In another aspect, a communication device may contend for access on a legacy system, and then communicate according to a new class communication protocol with one or more remote communication devices during the access period. In another aspect, a device may request access to a shared medium according to a legacy protocol, and, upon grant of access, the device may communicate with or facilitate communication between one or more remote stations according to a new protocol.

Abstract: Interference that occurs during wireless communication may be managed through the use of beam and null steering techniques. A method, apparatus and medium of communication determine an interference direction of a non-associated access terminal generating an interfering signal. Transmitted and received signals are then transceived away from the interference direction.

Abstract: Techniques for transmitting data using channel information for a subset of all subcarriers used for data transmission are described. A transmitter station receives channel information for at least one subcarrier that is a subset of multiple subcarriers used for data transmission. The channel information may include at least one transmit steering matrix, at least one set of eigenvectors, at least one channel response matrix, at least one channel covariance matrix, an unsteered pilot, or a steered pilot for the at least one subcarrier. The transmitter station obtains at least one transmit steering matrix for the at least one subcarrier from the channel information and determines a transmit steering matrix for each of the multiple subcarriers. The transmitter station performs transmit steering or beam-steering for each of the multiple subcarriers with the transmit steering matrix for that subcarrier.

Abstract: Mesh Network Access Points (APs) points, including gateways and routers, are deployed over a geographic area. The APs monitor the communication channel for other carriers and transmit accordingly. The APs selectively co-transmit when other carriers are sensed, if the efficiency of the mesh network will improve. APs select a transmission rate based on observed carrier-to-interference ratios. APs use directional antennas to increase carrier-to-interference ratios and spectral efficiency. AP transmit schedules are adaptable and adjusted according to observed carrier-to-interference measurements.

Abstract: Techniques for extending transmission range in a WLAN are described. In an aspect, a receiving station determines the frequency error between a transmitting station and the receiving station based on one or more initial packet transmissions and corrects this frequency error for subsequent packet transmissions received from the transmitting station. The residual frequency error is small after correcting for the frequency error and allows the receiving station to perform coherent accumulation/integration over a longer time interval to detect for a packet transmission. The longer coherent accumulation interval improves detection performance, especially at low SNRs for extended transmission range. The techniques may be used whenever the receiving station knows the identity of the transmitting station, e.g., if the subsequent packet transmissions are scheduled. Other aspects, features, and embodiments are also claimed and described.

Abstract: Embodiments addressing MAC processing for efficient use of high throughput systems are disclosed. In one aspect, a protocol stack is disclosed comprising one or more of the following: an adaptation layer, a data link control layer, a physical layer, and a layer manager. In another aspect, physical layer feedback is used for adaptation layer processing. In one embodiment, physical layer feedback is used for segmentation. In another embodiment, physical layer feedback is used for multicast mapping onto one or more unicast channels. In another aspect, a data unit for transmission from a first station to a second station comprises zero or more complete sub-data units, zero or one partial sub-data units from a prior transmission, and zero or one partial sub-data units to fill the data unit. In one embodiment, a pointer may be used to indicate the location of any complete sub-data units.

Abstract: A “unified” MIMO system that supports multiple operating modes for efficient data transmission is described. Each operating mode is associated with different spatial processing at a transmitting entity. For example, four operating modes may be defined for (1) full-CSI or partial-CSI transmission and (2) with or without steering transmit diversity (STD). An appropriate operating mode may be selected for use based on various factors (e.g., availability of a good channel estimate). With steering transmit diversity, data is spatially spread and transmitted on multiple spatial channels, and a single rate may then be used for all spatial channels used for data transmission. A receiving entity may utilize a minimum mean square error (MMSE) technique for all operating modes. The receiving entity may derive a spatial filter matrix and perform receiver spatial processing in the same manner for all operating modes, albeit with different effective channel response matrices.

Abstract: Certain aspects of the present disclosure propose a method and an apparatus for antenna tuning and transmit path selection in an RF system. A method may include antenna diversity path selection by (optionally) diagnosing damaged antennas, tuning antennas, and selecting an antenna with better performance. Embodiments can be used in wireless radio-frequency (RF) front-ends. Other aspects, embodiments, and features are also claimed and described.

Abstract: Techniques to calibrate downlink and uplink channels to account for differences in the frequency responses of transmit and receive chains are described. In one embodiment, pilots are transmitted on downlink and uplink channels and used to derive estimates of the downlink and uplink channel responses, respectively. Sets of correction factors are then determined based on estimates of downlink and uplink channel responses. A calibrated downlink channel is formed using a first set of correction factors for the downlink channel, and a calibrated uplink channel is formed using a second set of correction factors for the uplink channel. The first and second sets of correction factors may be determined using a matrix-ratio computation or a minimum mean square error computation. The calibration may be performed in real-time based on over-the-air transmission. Other aspects, embodiments, and features are also claimed and described.

Abstract: Mesh Network Access Points (APs) points, including gateways and routers, are deployed over a geographic area. The APs monitor the communication channel for other carriers and transmit accordingly. The APs selectively co-transmit when other carriers are sensed, if the efficiency of the mesh network will improve. APs select a transmission rate based on observed carrier-to-interference ratios. APs use directional antennas to increase carrier-to-interference ratios and spectral efficiency. AP transmit schedules are adaptable and adjusted according to observed carrier-to-interference measurements.

Abstract: Techniques for extending transmission range in a WLAN are described. In an aspect, a receiving station determines the frequency error between a transmitting station and the receiving station based on one or more initial packet transmissions and corrects this frequency error for subsequent packet transmissions received from the transmitting station. The residual frequency error is small after correcting for the frequency error and allows the receiving station to perform coherent accumulation/integration over a longer time interval to detect for a packet transmission. The longer coherent accumulation interval improves detection performance, especially at low SNRs for extended transmission range. The techniques may be used whenever the receiving station knows the identity of the transmitting station, e.g., if the subsequent packet transmissions are scheduled. Other aspects, embodiments, and features are also claimed and described.

Abstract: Techniques for facilitating random access in wireless multiple-access communication systems are described. A random access channel (RACH) is defined to comprise a “fast” RACH (F-RACH) and a “slow” RACH (S-RACH). The F-RACH and S-RACH can efficiently support user terminals in different operating states and employ different designs. The F-RACH can be used to quickly access the system, and the S-RACH is more robust and can support user terminals in various operating states and conditions. The F-RACH may be used by user terminals that have registered with the system and can compensate for their round trip delays (RTDs) by properly advancing their transmit timing. The S-RACH may be used by user terminals that may or may not have registered with the system, and may or may not be able to compensate for their RTDs. Other aspects, embodiments, and features are also claimed and described.

Abstract: Mesh Network Access Points (APs) points, including gateways and routers, are deployed over a geographic area. The APs monitor the communication channel for other carriers and transmit accordingly. The APs selectively co-transmit when other carriers are sensed, if the efficiency of the mesh network will improve. APs select a transmission rate based on observed carrier-to-interference ratios. APs use directional antennas to increase carrier-to-interference ratios and spectral efficiency. AP transmit schedules are adaptable and adjusted according to observed carrier-to-interference measurements.

Abstract: Techniques for using at least one of omni-directional and directional antennas for communication are described. A station may be equipped antenna elements selectable for use as an omni-directional antenna or one or more directional antennas. The station may select the omni-directional antenna or a directional antenna for use for communication based on various factors such as, e.g., whether the location or direction of a target station for communication is known, whether control frames or data frames are being exchanged, etc.