摘要:
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.
摘要:
A collection of nodes in a peer-to-peer (P2P) network can have a larger aggregate coverage footprint than any given single node. This inherent multi-site property of P2P wireless networks can provide each node with benefits of multi-user diversity. This can improve the effective coverage of nodes within a P2P wireless network and improve discovery of devices in the P2P network.
摘要:
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.
摘要:
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.
摘要:
Techniques to support beamforming for stations in a wireless network are described. A station may support beamforming with implicit or explicit feedback by having capabilities to transmit and receive sounding frames, responding to training request by sending a sounding frame, and responding to request for explicit feedback. In one explicit beamforming embodiment, the station may send a first frame with an explicit feedback request and may also send a Null Data Packet (NDP) having at least one training field but no data field. The station may receive a second frame with explicit feedback, which may be derived based on the NDP. The station may derive steering information based on explicit feedback and may then send a steered frame with beamforming based on the steering information. Other aspects, embodiments, and features are also claimed and described.
摘要:
Techniques for facilitating random access in wireless multiple-access communication systems. 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. The user terminals may use the F-RACH or S-RACH, or both, to gain access to the system.
摘要:
Techniques to calibrate the downlink and uplink channels to account for differences in the frequency responses of the transmit and receive chains at an access point and a user terminal. In one embodiment, pilots are transmitted on the downlink and uplink channels and used to derive estimates of the downlink and uplink channel responses, respectively. Two sets of correction factors are then determined based on the estimates of the downlink and uplink channel responses. A calibrated downlink channel is formed by using a first set of correction factors for the downlink channel, and a calibrated uplink channel is formed by 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 (MMSE) computation. The calibration may be performed in real-time based on over-the-air transmission.
摘要:
An access point in a multi-antenna system broadcasts data using spatial spreading to randomize an “effective” channel observed by each user terminal for each block of data symbols broadcast by the access point. At the access point, data is coded, interleaved, and modulated to obtain ND data symbol blocks to be broadcast in NM transmission spans, where ND≧1 and NM>1. The ND data symbol 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) 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 broadcast via NT transmit antennas and in one transmission span to user terminals within a broadcast coverage area.
摘要:
Techniques for decomposing matrices using Jacobi rotation are described. Multiple iterations of Jacobi rotation are performed on a first matrix of complex values with multiple Jacobi rotation matrices of complex values to zero out the off-diagonal elements in the first matrix. For each iteration, a submatrix may be formed based on the first matrix and decomposed to obtain eigenvectors for the submatrix, and a Jacobi rotation matrix may be formed with the eigenvectors and used to update the first matrix. A second matrix of complex values, which contains orthogonal vectors, is derived based on the Jacobi rotation matrices. For eigenvalue decomposition, a third matrix of eigenvalues may be derived based on the Jacobi rotation matrices. For singular value decomposition, a fourth matrix with left singular vectors and a matrix of singular values may be derived based on the Jacobi rotation matrices.
摘要:
In one disclosed embodiment, an input bit stream is supplied to a trellis code block. For example, the trellis code block can perform convolutional coding using a rate 6/7 code. The output of the trellis code block is then modulated using, for example, trellis coded quadrature amplitude modulation with 128 signal points or modulation symbols. The sequence of modulation symbols thus generated can be diversity encoded. The diversity encoding can be either a space time encoding, for example, or a space frequency encoding. The sequence of modulation symbols, or the sequence of diversity encoded modulation symbols, is fed to two or more orthogonal Walsh covers. For example, replicas of the modulation symbol sequences can be provided to increase diversity, or demultiplexing the modulation symbol sequences can be used to increase data transmission rate or “throughput.” The outputs of the Walsh covers are fed as separate inputs into a communication channel.