公开(公告)号：HK1108535A1

公开(公告)日：2008-05-09

申请号：HK08102451

申请日：2008-03-04

Applicant: QUALCOMM INC

Inventor： NANDA SANJIV ,  SURINENI SHRAVAN K ,  WALTON J RODNEY

IPC: H04L20060101 ,  H04Q20090101

公开(公告)号：CA2652225A1

公开(公告)日：2007-12-13

申请号：CA2652225

申请日：2007-05-30

Applicant: QUALCOMM INC

Inventor： WALTON J RODNEY ,  HOWARD STEVEN J ,  WALLACE MARK ,  SURINENI SHRAVAN K

IPC: H04L12/28 ,  H04B7/06 ,  H04L1/16 ,  H04L12/56

Abstract: Techniques for quickly sending feedback information for beamforming are d escribed. A transmitter/initiator sends a first frame comprising training sy mbols. A receiver/responder receives the first frame, determines the amount of time to generate feedback information, and determines the amount of time to send the feedback information. The receiver then determines the length of a second frame carrying the feedback information based on the amounts of ti me to generate and send the feedback information. The receiver sends the sec ond frame after waiting a short interframe space (SIFS) period from the end of the first frame, without performing channel access. The receiver generate s the feedback information based on the training symbols and sends the infor mation in the second frame when ready. The transmitter receives the second f rame, derives at least one steering matrix based on the feedback information , and sends a third frame with the at least one steering matrix.

公开(公告)号：CA2774221A1

公开(公告)日：2007-11-29

申请号：CA2774221

申请日：2007-05-22

Applicant: QUALCOMM INC

Inventor： WALTON J RODNEY ,  WALLACE MARK S ,  MEDVEDEV IRINA ,  HOWARD STEVEN J

IPC: H04B7/01 ,  H04B1/12 ,  H04B1/76 ,  H04B7/02 ,  H04J11/00

公开(公告)号：CA2732214A1

公开(公告)日：2006-08-03

申请号：CA2732214

申请日：2006-01-27

Applicant: QUALCOMM INC

Inventor： WALLACE MARK S ,  KETCHUM JOHN W ,  WALTON J RODNEY ,  HOWARD STEVEN J

IPC: H04J99/00 ,  H04W28/06 ,  H04B7/005 ,  H04B7/04 ,  H04B7/06 ,  H04B7/08 ,  H04L1/00 ,  H04L1/06 ,  H04L1/08 ,  H04L1/16 ,  H04L5/14 ,  H04L12/28 ,  H04L12/56 ,  H04L25/02 ,  H04L25/03 ,  H04L27/26 ,  H04W4/20 ,  H04W92/10

Abstract: Techniques are described 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 method, pilots are transmitted on the downlink and uplink channels and used to derive estimates of the downlink and uplink channel responses, respectively. Correction factors for the access point and correction factors for the user terminal are determined based on (e.g., by performing matrix-ratio computation or minimum mean square error (MMSE) computation on) the downlink and uplink channel response estimates. The correction factors for the access point and the correction factors for the user terminal are used to obtain a calibrated downlink channel and a calibrated uplink channel, which are transpose of one another. The calibration may be performed in real time based on over-the-air transmission.

公开(公告)号：AU2003287294A1

公开(公告)日：2004-05-13

申请号：AU2003287294

申请日：2003-10-24

Applicant: QUALCOMM INC

Inventor： HOWARD STEVEN J ,  WALTON J RODNEY ,  KETCHUM JOHN W ,  WALLACE MARK

IPC: H04B7/005 ,  H04B7/04 ,  H04B7/06 ,  H04B7/08 ,  H04J99/00 ,  H04L1/00 ,  H04L1/06 ,  H04L1/08 ,  H04L1/16 ,  H04L12/28 ,  H04L12/56 ,  H04L25/02 ,  H04L25/03 ,  H04L27/26 ,  H04W28/20 ,  H04W52/50 ,  H04W74/08 ,  H04B7/00

Abstract: 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.

公开(公告)号：CA2810036A1

公开(公告)日：2004-05-06

申请号：CA2810036

申请日：2003-10-24

Applicant: QUALCOMM INC

Inventor： WALTON J RODNEY ,  KETCHUM JOHN W ,  WALLACE MARK S ,  HOWARD STEVEN J

IPC: H04W74/08 ,  H04B7/005 ,  H04B7/04 ,  H04B7/06 ,  H04B7/08 ,  H04J99/00 ,  H04L1/00 ,  H04L1/06 ,  H04L1/08 ,  H04L1/16 ,  H04L12/28 ,  H04L12/56 ,  H04L25/02 ,  H04L25/03 ,  H04L27/26 ,  H04W28/20 ,  H04W52/50

Abstract: 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.

公开(公告)号：CA2501285A1

公开(公告)日：2004-05-06

申请号：CA2501285

申请日：2003-10-24

Applicant: QUALCOMM INC

Inventor： WALLACE MARK S ,  HOWARD STEVEN J ,  WALTON J RODNEY ,  KETCHUM JOHN W

IPC: H04B7/005 ,  H04B7/04 ,  H04B7/06 ,  H04B7/08 ,  H04J99/00 ,  H04L1/00 ,  H04L1/06 ,  H04L1/08 ,  H04L1/16 ,  H04L12/28 ,  H04L12/56 ,  H04L25/02 ,  H04L25/03 ,  H04L27/26 ,  H04W16/28 ,  H04W52/50

Abstract: A user terminal supports multiple spatial multiplexing (SM) modes such as a steered mode and a non-steered mode. For data transmission, multiple data streams are coded and modulated in accordance with their selected rates to obtain multiple data symbol streams. These streams are then spatially processed in accordance with a selected SM mode (e.g., with a matrix of steering vectors for the steered mode and with the identity matrix for the n on- steered mode) to obtain multiple transmit symbol streams for transmission fr om multiple antennas. For data reception, multiple received symbol streams are spatially processed in accordance with the selected SM mode (e.g., with a matrix of eigenvectors for the steered mode and with a spatial filter matrix for the non-steered mode) to obtain multiple recovered data symbol streams. These streams are demodulated and decoded in accordance with their selected rates to obtain multiple decoded data streams.

公开(公告)号：CA2500849A1

公开(公告)日：2004-05-06

申请号：CA2500849

申请日：2003-10-24

Applicant: QUALCOMM INC

Inventor： WALTON J RODNEY ,  WALLACE MARK S

IPC: H04B7/005 ,  H04B7/06 ,  H04B7/08 ,  H04J99/00 ,  H04L1/00 ,  H04L1/06 ,  H04L1/08 ,  H04L1/16 ,  H04L25/02 ,  H04L25/03 ,  H04L27/00 ,  H04L27/26 ,  H04W28/20 ,  H04W52/50

Abstract: Techniques for detecting and demodulating data transmissions in wireless communication systems. In one aspect, a decision-directed detector detects f or data transmissions in a received signal by utilizing received data symbols a s well as received pilot symbols. The decision-directed detector may be design ed to perform differential detection in the frequency domain or coherent detection in the time domain, and may be used with multi-carrier modulation (e.g., OFDM). In another aspect, an adaptive threshold is used to perform detection of received data transmissions. A threshold may be determined for each data transmission hypothesized to have been received. The threshold may be computed, for example, based on the signal plus noise energy of the hypothesized data transmission.

公开(公告)号：CA2753403C

公开(公告)日：2015-05-19

申请号：CA2753403

申请日：2003-10-24

Applicant: QUALCOMM INC

Inventor： KETCHUM JOHN W ,  WALLACE MARK S ,  WALTON J RODNEY ,  HOWARD STEVEN J

IPC: H04W24/00 ,  H04B1/76 ,  H04B7/005 ,  H04B7/02 ,  H04B7/04 ,  H04B7/06 ,  H04B7/08 ,  H04J99/00 ,  H04L1/00 ,  H04L1/06 ,  H04L1/08 ,  H04L1/16 ,  H04L12/28 ,  H04L12/56 ,  H04L25/02 ,  H04L25/03 ,  H04L27/26 ,  H04W16/28 ,  H04W52/50

Abstract: Channel estimation and spatial processing for a TDD MIMO system. Calibration may be performed to account for differences in the responses of transmit/receive chains at the access point and user terminal. During normal operation, a MIMO pilot is transmitted on a first link and used to derive an estimate of the first link channel response, which is decomposed to obtain a diagonal matrix of singular values and a first unitary matrix containing both left eigenvectors of the first link and right eigenvectors of a second link. A steered reference is transmitted on the second link using the eigenvectors in the first unitary matrix, and is processed to obtain the diagonal matrix and a second unitary matrix containing both left eigenvectors of the second link and right eigenvectors of the first link. Each unitary matrix may be used to perform spatial processing for data transmission/reception via both links.

公开(公告)号：CA2500355C

公开(公告)日：2014-12-16

申请号：CA2500355

申请日：2003-10-24

Applicant: QUALCOMM INC

Inventor： WALTON J RODNEY ,  WALLACE MARK S ,  KETCHUM JOHN W ,  HOWARD STEVEN J

IPC: H04W72/04 ,  H04B7/005 ,  H04B7/06 ,  H04B7/08 ,  H04J99/00 ,  H04L1/00 ,  H04L1/06 ,  H04L1/08 ,  H04L1/16 ,  H04L1/18 ,  H04L12/28 ,  H04L12/56 ,  H04L25/02 ,  H04L25/03 ,  H04L27/00 ,  H04L27/26 ,  H04W28/06 ,  H04W28/20 ,  H04W28/22 ,  H04W52/00 ,  H04W52/42 ,  H04W52/50 ,  H04W72/12 ,  H04W74/00 ,  H04W74/08 ,  H04W84/12 ,  H04W88/12

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.