Patent application number | Description | Published |
20080267098 | MIMO SYSTEM WITH MULTIPLE SPATIAL MULTIPLEXING MODES - A MIMO system supports multiple spatial multiplexing modes for improved performance and greater flexibility. These modes may include (1) a single-user steered mode that transmits multiple data streams on orthogonal spatial channels to a single receiver, (2) a single-user non-steered mode that transmits multiple data streams from multiple antennas to a single receiver without spatial processing at a transmitter, (3) a multi-user steered mode that transmits multiple data streams simultaneously to multiple receivers with spatial processing at a transmitter, and (4) a multi-user non-steered mode that transmits multiple data streams from multiple antennas (co-located or non co-located) without spatial processing at the transmitter(s) to receiver(s) having multiple antennas. For each set of user terminal(s) selected for data transmission on the downlink and/or uplink, a spatial multiplexing mode is selected for the user terminal set from among the multiple spatial multiplexing modes supported by the system. | 10-30-2008 |
20080267138 | MIMO SYSTEM WITH MULTIPLE SPATIAL MULTIPLEXING MODES - A MIMO system supports multiple spatial multiplexing modes for improved performance and greater flexibility. These modes may include (1) a single-user steered mode that transmits multiple data streams on orthogonal spatial channels to a single receiver, (2) a single-user non-steered mode that transmits multiple data streams from multiple antennas to a single receiver without spatial processing at a transmitter, (3) a multi-user steered mode that transmits multiple data streams simultaneously to multiple receivers with spatial processing at a transmitter, and (4) a multi-user non-steered mode that transmits multiple data streams from multiple antennas (co-located or non co-located) without spatial processing at the transmitter(s) to receiver(s) having multiple antennas. For each set of user terminal(s) selected for data transmission on the downlink and/or uplink, a spatial multiplexing mode is selected for the user terminal set from among the multiple spatial multiplexing modes supported by the system. | 10-30-2008 |
20080285488 | MIMO WLAN SYSTEM - 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. | 11-20-2008 |
20080285664 | MODE AND RATE CONTROL FOR MIMO TRANSMISSION - Techniques for performing mode and rate control for a MIMO transmission are described. For mode selection, the use of an eigensteering mode is permitted if a first set of at least one criterion is satisfied. The eigensteering mode is selected for data transmission if a second set of at least one criterion is satisfied, and an unsteered mode is selected otherwise. For rate selection, SNR estimates are derived for data streams to potentially transmit, e.g., based on channel estimates and/or data symbol estimates. The number of data streams to transmit as well as at least one rate for at least one data stream to transmit are selected based on the SNR estimates and at least one backoff factor. The backoff factor(s) are adjusted based on status of received packets. The at least one rate may be adjusted based on the age of rate information. | 11-20-2008 |
20080285669 | MIMO WLAN SYSTEM - 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. | 11-20-2008 |
20080285670 | MIMO WLAN SYSTEM - 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. | 11-20-2008 |
20090092087 | MULTI-ANTENNA TRANSMISSION FOR SPATIAL DIVISION MULTIPLE ACCESS - An uplink channel response matrix is obtained for each terminal and decomposed to obtain a steering vector used by the terminal to transmit on the uplink. An “effective” uplink channel response vector is formed for each terminal based on its steering vector and its channel response matrix. Multiple sets of terminals are evaluated based on their effective channel response vectors to determine the best set (e.g., with highest overall throughput) for uplink transmission. Each selected terminal performs spatial processing on its data symbol stream with its steering vector and transmits its spatially processed data symbol stream to an access point. The multiple selected terminals simultaneously transmit their data symbol streams via their respective MIMO channels to the access point. The access point performs receiver spatial processing on its received symbol streams in accordance with a receiver spatial processing technique to recover the data symbol streams transmitted by the selected terminals. | 04-09-2009 |
20090122927 | RECEIVER FOR WIRELESS COMMUNICATION NETWORK WITH EXTENDED RANGE - Techniques for detecting and demodulating a signal/transmission are described. Signal detection is performed in multiple stages using different types of signal processing, e.g., using time-domain correlation for a first stage, frequency-domain processing for a second stage, and time-domain processing for a third stage. For the first stage, products of symbols are generated for at least two different delays, correlation between the products for each delay and known values is performed, and correlation results for all delays are combined and used to declare the presence of a signal. For demodulation, the timing of input samples is adjusted to obtain timing-adjusted samples. A frequency offset is estimated and removed from the timing-adjusted samples to obtain frequency-corrected samples, which are processed with a channel estimate to obtain detected symbols. The phases of the detected symbols are corrected to obtain phase-corrected symbols, which are demodulated, deinterleaved, and decoded. | 05-14-2009 |
20090129454 | RATE SELECTION WITH MARGIN SHARING - Rate selection with margin sharing in a system with independent data stream rates is presented. Signal-to-Noise Ratio (SNR) estimates are obtained for each stream. Rates are selected for the streams based on the SNR estimates, such that at least one data stream has an SNR margin below a threshold, each remaining data stream has an SNR margin above a respective threshold, and the total SNR margin for all streams is above a total threshold. For rate selection with margin sharing with a vector-quantized rate set, SNR estimates are obtained for usable transmission channels. The total SNR margin is determined for each rate combination based on the estimates. Each rate combination is associated with a specific number of data streams to transmit, a specific rate for each data stream, and a specific overall throughput. The combination with the highest overall throughput and non-negative total SNR margin is selected. | 05-21-2009 |
20090290664 | RECEIVER FOR WIRELESS COMMUNICATION NETWORK WITH EXTENDED RANGE - Techniques for detecting and demodulating a signal/transmission are described. Signal detection is performed in multiple stages using different types of signal processing, e.g., using time-domain correlation for a first stage, frequency-domain processing for a second stage, and time-domain processing for a third stage. For the first stage, products of symbols are generated for at least two different delays, correlation between the products for each delay and known values is performed, and correlation results for all delays are combined and used to declare the presence of a signal. For demodulation, the timing of input samples is adjusted to obtain timing-adjusted samples. A frequency offset is estimated and removed from the timing-adjusted samples to obtain frequency-corrected samples, which are processed with a channel estimate to obtain detected symbols. The phases of the detected symbols are corrected to obtain phase-corrected symbols, which are demodulated, deinterleaved, and decoded. | 11-26-2009 |
20100002570 | Transmit diversity and spatial spreading for an OFDM-based multi-antenna communication system - A multi-antenna transmitting entity transmits data to a single- or multi-antenna receiving entity using (1) a steered mode to direct the data transmission toward the receiving entity or (2) a pseudo-random transmit steering (PRTS) mode to randomize the effective channels observed by the data transmission across the subbands. The PRTS mode may be used to achieve transmit diversity or spatial spreading. For transmit diversity, the transmitting entity uses different pseudo-random steering vectors across the subbands but the same steering vector across a packet for each subband. The receiving entity does not need to have knowledge of the pseudo-random steering vectors or perform any special processing. For spatial spreading, the transmitting entity uses different pseudo-random steering vectors across the subbands and different steering vectors across the packet for each subband. Only the transmitting and receiving entities know the steering vectors used for data transmission. | 01-07-2010 |
20100020757 | RESOURCE ALLOCATION FOR MIMO-OFDM COMMUNICATION SYSTEMS - Techniques to schedule terminals for data transmission on the downlink and/or uplink in a MIMO-OFDM system based on the spatial and/or frequency “signatures” of the terminals. A scheduler forms one or more sets of terminals for possible (downlink or uplink) data transmission for each of a number of frequency bands. One or more sub-hypotheses may further be formed for each hypothesis, with each sub-hypothesis corresponding to (1) specific assignments of transmit antennas to the terminal(s) in the hypothesis (for the downlink) or (2) a specific order for processing the uplink data transmissions from the terminal(s) (for the uplink). The performance of each sub-hypothesis is then evaluated (e.g., based on one or more performance metrics). One sub-hypothesis is then selected for each frequency band based on the evaluated performance, and the one or more terminals in each selected sub-hypothesis are then scheduled for data transmission on the corresponding frequency band. | 01-28-2010 |
20100067401 | METHODS AND SYSTEMS FOR TRANSMISSION MODE SELECTION IN A MULTI CHANNEL COMMUNICATION SYSTEM - Techniques to select a suitable transmission mode for a data transmission in a multi channel communication system with multiple spatial channels having varying SNRs are presented in this disclosure. For certain embodiments, a closed-loop technique may be applied, in which back-off factors used to calculate an effective SNR value fed back to a transmitter are adjusted. An open-loop rate control scheme is also presented in which a transmitter may select a data rate and number of streams based on whether transmitted packets are received in error at a receiver. | 03-18-2010 |
20100067590 | ADAPTIVE PILOT INSERTION FOR A MIMO-OFDM SYSTEM - A transmitting entity transmits a “base” pilot in each protocol data unit (PDU). A receiving entity is able to derive a sufficiently accurate channel response estimate of a MIMO channel with the base pilot under nominal (or most) channel conditions. The transmitting entity selectively transmits an additional pilot if and as needed, e.g., based on channel conditions and/or other factors. The additional pilot may be adaptively inserted in almost any symbol period in the PDU. The receiving entity is able to derive an improved channel response estimate with the additional pilot. The transmitting entity sends signaling to indicate that additional pilot is being sent. This signaling may be embedded within pilot symbols sent on a set of pilot subbands used for a carrier pilot that is transmitted across most of the PDU. The signaling indicates whether additional pilot is being sent and possibly other pertinent information. | 03-18-2010 |
20100119001 | MIMO SYSTEM WITH MULTIPLE SPATIAL MULTIPLEXING MODES - A MIMO system supports multiple spatial multiplexing modes for improved performance and greater flexibility. These modes may include (1) a single-user steered mode that transmits multiple data streams on orthogonal spatial channels to a single receiver, (2) a single-user non-steered mode that transmits multiple data streams from multiple antennas to a single receiver without spatial processing at a transmitter, (3) a multi-user steered mode that transmits multiple data streams simultaneously to multiple receivers with spatial processing at a transmitter, and (4) a multi-user non-steered mode that transmits multiple data streams from multiple antennas (co-located or non co-located) without spatial processing at the transmitter(s) to receiver(s) having multiple antennas. For each set of user terminal(s) selected for data transmission on the downlink and/or uplink, a spatial multiplexing mode is selected for the user terminal set from among the multiple spatial multiplexing modes supported by the system. | 05-13-2010 |
20100208841 | TRANSMIT DIVERSITY PROCESSING FOR A MULTI-ANTENNA COMMUNICATION SYSTEM - For transmit diversity in a multi-antenna OFDM system, a transmitter encodes, interleaves, and symbol maps traffic data to obtain data symbols. The transmitter processes each pair of data symbols to obtain two pairs of transmit symbols for transmission from a pair of antennas either (1) in two OFDM symbol periods for space-time transmit diversity or (2) on two subbands for space-frequency transmit diversity. N | 08-19-2010 |
20110055326 | METHODS AND SYSTEMS FOR SERVICE DISCOVERY MANAGEMENT IN PEER-TO-PEER NETWORKS - Certain embodiments of the present disclosure relate to a method and an apparatus for managing and optimizing service discovery in a peer-to-peer (P2P) wireless network. Nodes of the P2P network advertise their capabilities to their peers in the form of services. Efficient propagation and management of node's services to other nodes is proposed in the present disclosure. | 03-03-2011 |
20110103523 | SINGLE-BURST ACQUISITION FOR WIRELESS COMMUNICATION SYSTEM - 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. | 05-05-2011 |
20110235744 | PILOTS FOR MIMO COMMUNICATION SYSTEMS - Pilots suitable for use in MIMO systems and capable of supporting various functions are described. The various types of pilot include—a beacon pilot, a MIMO pilot, a steered reference or steered pilot, and a carrier pilot. The beacon pilot is transmitted from all transmit antennas and may be used for timing and frequency acquisition. The MIMO pilot is transmitted from all transmit antennas but is covered with different orthogonal codes assigned to the transmit antennas. The MIMO pilot may be used for channel estimation. The steered reference is transmitted on specific eigenmodes of a MIMO channel and is user terminal specific. The steered reference may be used for channel estimation. The carrier pilot may be transmitted on designated subbands/antennas and may be used for phase tracking of a carrier signal. Various pilot transmission schemes may be devised based on different combinations of these various types of pilot. | 09-29-2011 |
20120033618 | MODE AND RATE CONTROL FOR MIMO TRANSMISSION - Techniques for performing mode and rate control for a MIMO transmission are described. For mode selection, the use of an eigensteering mode is permitted if a first set of at least one criterion is satisfied. The eigensteering mode is selected for data transmission if a second set of at least one criterion is satisfied, and an unsteered mode is selected otherwise. For rate selection, SNR estimates are derived for data streams to potentially transmit, e.g., based on channel estimates and/or data symbol estimates. The number of data streams to transmit as well as at least one rate for at least one data stream to transmit are selected based on the SNR estimates and at least one backoff factor. The backoff factor(s) are adjusted based on status of received packets. The at least one rate may be adjusted based on the age of rate information. Other aspects, features, and embodiments are also claimed and described. | 02-09-2012 |
20120140664 | RANDOM ACCESS FOR WIRELESS MULTIPLE-ACCESS COMMUNICATION SYSTEMS - 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. | 06-07-2012 |
20120213181 | TRANSMIT DIVERSITY AND SPATIAL SPREADING FOR AN OFDM-BASED MULTI-ANTENNA COMMUNICATION SYSTEM - A multi-antenna transmitting entity transmits data to a single- or multi-antenna receiving entity using (1) a steered mode to direct the data transmission toward the receiving entity or (2) a pseudo-random transmit steering (PRTS) mode to randomize the effective channels observed by the data transmission across the subbands. For transmit diversity, the transmitting entity uses different pseudo-random steering vectors across the subbands but the same steering vector across a packet for each subband. The receiving entity does not need to have knowledge of the pseudo-random steering vectors or perform any special processing. For spatial spreading, the transmitting entity uses different pseudo-random steering vectors across the subbands and different steering vectors across the packet for each subband. Only the transmitting and receiving entities know the steering vectors used for data transmission. Other aspects, embodiments, and features are also claimed and disclosed. | 08-23-2012 |
20120213302 | MULTI-ANTENNA TRANSMISSION FOR SPATIAL DIVISION MULTIPLE ACCESS - An uplink channel response matrix is obtained for each terminal and decomposed to obtain a steering vector used by the terminal to transmit on the uplink. An “effective” uplink channel response vector is formed for each terminal based on its steering vector and its channel response matrix. Multiple sets of terminals are evaluated based on their effective channel response vectors to determine the best set (e.g., with highest overall throughput) for uplink transmission. Each selected terminal performs spatial processing on its data symbol stream with its steering vector and transmits its spatially processed data symbol stream to an access point. The multiple selected terminals simultaneously transmit their data symbol streams via their respective MIMO channels to the access point. The access point performs receiver spatial processing on its received symbol streams in accordance with a receiver spatial processing technique to recover the data symbol streams transmitted by the selected terminals. | 08-23-2012 |
20130182598 | METHODS AND SYSTEMS FOR TRANSMISSION MODE SELECTION IN A MULTI CHANNEL COMMUNICATION SYSTEM - Techniques to select a suitable transmission mode for a data transmission in a multi channel communication system with multiple spatial channels having varying SNRs are presented in this disclosure. For certain embodiments, a closed-loop technique may be applied, in which back-off factors used to calculate an effective SNR value fed back to a transmitter are adjusted. An open-loop rate control scheme is also presented in which a transmitter may select a data rate and number of streams based on whether transmitted packets are received in error at a receiver. | 07-18-2013 |
20130182614 | PEER-TO-PEER COMMUNICATION IN AD HOC WIRELESS NETWORK - For a peer-to-peer call in an ad hoc wireless network, a wireless device performs discovery of a target wireless device, performs authentication of the target wireless device and generates a session key (e.g., using a pre-shared key or a certificate provisioned on the wireless device), forms an ad hoc wireless network with the target wireless device, and communicates peer-to-peer with the target wireless device via the ad hoc wireless network. The wireless device may perform discovery with a list of identifiers for wireless devices designated to communicate with this wireless device. The wireless device may derive a service set identifier (SSID) used to identify the ad hoc wireless network based on its user-specific identifier (e.g., its phone number) and/or a user-specific identifier for the target wireless device. The wireless device may also performs IP address discovery using the user-specific identifier for the target wireless device. | 07-18-2013 |
20130235825 | MIMO SYSTEM WITH MULTIPLE SPATIAL MULTIPLEXING MODES - A MIMO system supports multiple spatial multiplexing modes for improved performance and greater flexibility. These modes may include (1) a single-user steered mode that transmits multiple data streams on orthogonal spatial channels to a single receiver, (2) a single-user non-steered mode that transmits multiple data streams from multiple antennas to a single receiver without spatial processing at a transmitter, (3) a multi-user steered mode that transmits multiple data streams simultaneously to multiple receivers with spatial processing at a transmitter, and (4) a multi-user non-steered mode that transmits multiple data streams from multiple antennas (co-located or non co-located) without spatial processing at the transmitter(s) to receiver(s) having multiple antennas. For each set of user terminal(s) selected for data transmission on the downlink and/or uplink, a spatial multiplexing mode is selected for the user terminal set from among the multiple spatial multiplexing modes supported by the system. | 09-12-2013 |
20130281086 | METHODS AND SYSTEMS FOR SERVICE DISCOVERY MANAGEMENT IN PEER-TO-PEER NETWORKS - Certain embodiments of the present disclosure relate to a method and an apparatus for managing and optimizing service discovery in a peer-to-peer (P2P) wireless network. Nodes of the P2P network advertise their capabilities to their peers in the form of services. Efficient propagation and management of node's services to other nodes is proposed in the present disclosure. | 10-24-2013 |
20130281146 | METHODS AND SYSTEMS FOR PEER-TO-PEER NETWORK DISCOVERY USING MULTI-USER DIVERSITY - Certain embodiments of the present disclosure relate to a method for improving the effective coverage of nodes within a peer-to-peer (P2P) wireless network. Collection of nodes of the P2P network can have a larger aggregate coverage footprint than any given single node. This inherent multi-site property of P2P wireless networks can be exploited to provide each node with benefits of multi-user diversity, thus improving discovery of devices in the P2P network. | 10-24-2013 |
20140056293 | PEER-TO-PEER COMMUNICATION IN AD HOC WIRELESS NETWORK - For a peer-to-peer call in an ad hoc wireless network, a wireless device performs discovery of a target wireless device, performs authentication of the target wireless device and generates a session key (e.g., using a pre-shared key or a certificate provisioned on the wireless device), forms an ad hoc wireless network with the target wireless device, and communicates peer-to-peer with the target wireless device via the ad hoc wireless network. The wireless device may perform discovery with a list of identifiers for wireless devices designated to communicate with this wireless device. The wireless device may derive a service set identifier (SSID) used to identify the ad hoc wireless network based on its user-specific identifier (e.g., its phone number) and/or a user-specific identifier for the target wireless device. Other aspects, embodiments, and features are also claimed and described. | 02-27-2014 |
20150085703 | METHODS AND SYSTEMS FOR EXPLOITATION OF WELL-CONNECTED NODES IN PEER-TO-PEER WIRELESS NETWORKS - Certain embodiments of the present disclosure relate to a method for increasing a capacity in a peer-to-peer (P2P) wireless network. A scheme has been proposed in which well-connected nodes of the P2P wireless network can be exploited in a manner that increases the overall connectivity of all the nodes in the network. | 03-26-2015 |
20150085751 | METHODS AND SYSTEMS FOR EXPLOITATION OF WELL-CONNECTED NODES IN PEER-TO-PEER WIRELESS NETWORKS - Certain embodiments of the present disclosure relate to a method for increasing a capacity in a peer-to-peer (P2P) wireless network. A scheme has been proposed in which well-connected nodes of the P2P wireless network can be exploited in a manner that increases the overall connectivity of all the nodes in the network. | 03-26-2015 |