In a data communication system capable of variable rate transmission, high rate packet data transmission improves utilization of the forward link and decreases the transmission delay. Data transmission on the forward link is time multiplexed and the base station transmits at the highest data rate supported by the forward link at each time slot to one mobile station. The data rate is determined by the largest C/I measurement of the forward link signals as measured at the mobile station. Upon determination of a data packet received in error, the mobile station transmits a NACK message back to the base station. The NACK message results in retransmission of the data packet received in error. The data packets can be transmitted out of sequence by the use of sequence number to identify each data unit within the data packets.

Method and apparatus for high-rate packet data transmission

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.

MIMO WLAN system

This paper presents the concept, principles, and analysis of maximum ratio transmission for wireless communications where multiple antennas are used for both transmission and reception. The principles and analysis are applicable to general cases, including maximum ratio combining. Simulation results agree with the analysis. The analysis shows that the average overall SNR is proportional to the cross-correlation between channel vectors and that error probability decreases inversely with the (L/spl times/K)th power of the average SNR.

Maximum ratio transmission

Techniques to process data for transmission over a set of transmission channels selected from among all available transmission channels. In an aspect, the data processing includes coding data based on a common coding and modulation scheme to provide modulation symbols and pre-weighting the modulation symbols for each selected channel based on the channel's characteristics. The pre-weighting may be achieved by “inverting” the selected channels so that the received SNRs are approximately similar for all selected channels. With selective channel inversion, only channels having SNRs at or above a particular threshold are selected, “bad” channels are not used, and the total available transmit power is distributed across only “good” channels. Improved performance is achieved due to the combined benefits of using only the NS best channels and matching the received SNR of each selected channel to the SNR required by the selected coding and modulation scheme.

Method and apparatus for processing data for transmission in a multi-channel communication system using selective channel inversion

Channel state information (CSI) can be used by a communications system to precondition transmissions between transmitter units and receiver units. In one aspect of the invention, disjoint sub-channel sets are assigned to transmit antennas located at a transmitter unit. Pilot symbols are generated and transmitted on a subset of the disjoint sub-channels. Upon receipt of the transmitted pilot symbols, the receiver units determine the CSI for the disjoint sub-channels that carried pilot symbols. These CSI values are reported to the transmitter unit, which will use these CSI values to generate CSI estimates for the disjoint sub-channels that did not carry pilot symbols. The amount of information necessary to report CSI on the reverse link can be further minimized through compression techniques and resource allocation techniques.

Method and apparatus for measuring and reporting channel state information in a high efficiency, high performance communications system

The present invention makes it possible to increase a data rate between a transmitter and receiver using a multiple-input, multiple-output radio frequency channel. A multiple-stream, multiple-antenna receiver measures a composite channel between a multiple-antenna transmitter and a multiple-antenna receiver to produce a composite channel measurement. The receiver selects a plurality of antenna array weight sets for use in the multiple-antenna transmitter in response to the composite channel measurement, where each antenna array weight set is associated with one of multiple data streams. Information describing the plurality of antenna array weight sets for use in the multiple-antenna transmitter are then transmitted.

Method and system in a transceiver for controlling a multiple-input, multiple-output communications channel

A communication system provides, via a single, serving Node B, scheduling information required by a user equipment (UE) to determine a start time for each Node B of multiple Node Bs with respect to a multicast, by each Node B of the multiple Node Bs, of soft combinable MBMS data. The UE may then use the scheduling information to synchronize a soft combining of the MBMS data received by the UE via each of the multiple Node Bs, even when the multicasts via the multiple Node Bs are not synchronized. However, while the multicasts of frames of data associated with an MBMS service by different Node Bs need not be synchronized, synchronized multicasts are preferable for soft combining. Therefore, the communication system further provides for a synchronization by a network controller of the multicasts of the soft combinable MBMS data by the multiple Node Bs.

Method and apparatus for scheduling and synchronizing a multimedia broadcast/multicast service

An apparatus is provided for use in a multi-channel digital transmitter and receiver. A filtering process is accomplished by conditioning portions of a digitized signal during digital signal processing by integrating, taking the difference of, and multiplying portions of the digitized signal. The filtering process may be used in conjunction with a receiving process to generate a digitized channel signal (166, 168, 170, 172) by conditioning (132, 134, 136, 138) the digitized signal (128) and subsequently Fourier transforming (148) the conditioned portions of the digitized signal. Alternatively, the filtering process may be used in conjunction with a transmitting process by inverse Fourier transforming (324) a plurality of digitized information signals (300, 302, 304, 306) to be transmitted, generating a composite digitized signal (352), and subsequently conditioning the composite digitized signal (358).

A multi-channel digital transmitter and receiver

A receiver (100), transmitter (200) and transceiver (400) in accordance with the present invention overcome the disadvantages of applying adaptive antenna array technology to multi-channel communication systems. Multi-channel radio frequency (RF) signals received via an adaptive antenna array (102) are converted from an analog form to a digital form prior to splitting and processing to recover communication channels contained therein. A number of digital communication signals are digitally combined into a multi-channel digital signal and converted from the digital form to an analog radio frequency form prior to transmission from the adaptive antenna array.

Multi-channel transceiver having an adaptive antenna array and method

In a transceiver for transmitting a communication signal from an antenna array in a wireless communications system, a different element pilot is transmitted from a plurality of antenna elements in an antenna array. Thereafter, transmitter control data based upon measured characteristics of the element pilots as measured at a subscriber unit is received at the transceiver. In response to the transmitter control data, a plurality of adaptive array weights for modifying a plurality of element communication signals are determined. Next, the transceiver determines that the subscriber unit is ready to receive a communication signal transmitted from the antenna array and weighted according to the plurality of adaptive array weights. In response to determining that the subscriber unit is ready, the transceiver modifies the plurality of element communication signals according to the determined plurality of adaptive array weights.

Robert M. Harrison

Papers

Method and system in a transceiver for controlling a multiple-input, multiple-output communications channel

Method and apparatus for scheduling and synchronizing a multimedia broadcast/multicast service

A multi-channel digital transmitter and receiver

Multi-channel transceiver having an adaptive antenna array and method

Method and system for transmitting and demodulating a communications signal using an adaptive antenna array in a wireless communication system