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

Techniques to implement MBMS services in a wireless communication system. In one aspect, a method is provided for processing data for transmission to a plurality of terminals. Frames of information bits (which may have variable rates) are provided to a buffer implementing a matrix. The matrix is padded with padding bits based on a particular padding scheme to support variable frame rates. The frames are then coded based on a particular block code to provide parity bits. The frame of information bits and the parity bits are then transmitted to the terminals. In another aspect, a method is provided for controlling the transmit power of a data transmission to a plurality of terminals. In accordance with the method, TPC streams are received from the terminals and processed to obtain a stream of joint power control commands used to adjust the transmit power of the data transmission.

Multi-media broadcast and multicast service (MBMS) in a wireless communication system

A digital broadcasting system and a method of processing data are disclosed, which are robust to error when mobile service data are transmitted. To this end, additional encoding is performed for the mobile service data, whereby it is possible to strongly cope with fast channel change while giving robustness to the mobile service data.

Digital broadcasting system and data processing method

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.

MIMO system with multiple spatial multiplexing modes

Methods and apparatus for a data transmission in a communication system are disclosed. Each of a subset of plural access terminals desiring to transmit user data in an interval transmits a request to transmit in the interval to an access network. The access network makes a decision to schedule at least one of the subset of the plural access terminals to transmit in the interval in accordance with the request. At least one access point of the access network transmits the decision to the plural access terminals.

Method and system for a data transmission in a communication system

The present invention provides a method and apparatus for providing improved quality or power control by recognizing the delays inherent in a closed-loop communication system. The mobile station (12) or receiver properly adjusts its forward link quality or power level thresholds or measurements with which it compares incoming frames or portions thereof to reflect the level it anticipates receiving (after the delay). For example, the mobile station (12) can recognize that at a given measurement time, two outstanding messages have not been executed by the transmitter (where each message indicates a corresponding increase of 1 dB). As a result, the mobile station (12) can adjust its measurement threshold down by 2 dB to more closely correspond to future power adjustments. If the currently received frame or portion thereof is still below the readjusted threshold, then the mobile station (12) sends out a new message to request a further increase in the forward link channel.

Method and apparatus for adjusting thresholds and measurements of received signals by anticipating power control commands yet to be executed

A method and apparatus for wireless communications wherein a base station (102) transmits a signal to sending data to a subscriber station (108) through a signal beam (110) that sweeps through the coverage area of the base station (102). User data addressed to the subscriber station (108) is buffered until the signal beam angle of the signal (110) beam allows efficient transmission. The base station (102) may alter the beam sweep speed or the shape of the beam's radiation pattern (106) over time to maximize system efficiency and capacity.

Wireless communication system with base station beam sweeping

Techniques to adjust the setpoint of a power control loop in a wireless communication system. The setpoint may be adjusted based on frame status indicative of erased/good decoded frames, one or more (typically soft) metrics indicative of the confidence in the decoded results, power surplus/deficit indicative of the difference between the received signal quality and the setpoint and a threshold Eb/Nt needed for the desired level of performance, or a combination thereof. The metrics may include re-encoded symbol error rate, re-encoded power metric, modified Yamamoto metric, minimum or average LLR among decoded bits, number of decoding iterations, and possibly others, The setpoint may be adjusted in different manners and/or by different amounts depending on the above-noted factors. The techniques may be employed for forward and/or reverse links in CDMA systems.

Method and apparatus for adjusting power control setpoint in a wireless communication system

Embodiments disclosed herein address the need in the art for reduced overhead control with the ability to adjust transmission rates as necessary. In one aspect, a first signal indicates an acknowledgement of a decoded subpacket and whether or not a rate control command is generated, and a second signal conditionally indicates the rate control command when one is generated. In another aspect, a grant may be generated concurrently with the acknowledgement. In yet another aspect, a mobile station monitors the first signal, conditionally monitors the second signal as indicated by the first signal, and may monitor a third signal comprising a grant. In yet another aspect, one or more base stations transmit one or more of the various signals. Various other aspects are also presented. These aspects have the benefit of providing the flexibility of grant-based control while utilizing lower overhead when rate control commands are used, thus increasing system utilization, increasing capacity and throughput.

Tao Chen

Papers

Multi-media broadcast and multicast service (MBMS) in a wireless communication system

Method and apparatus for adjusting thresholds and measurements of received signals by anticipating power control commands yet to be executed

Wireless communication system with base station beam sweeping

Method and apparatus for adjusting power control setpoint in a wireless communication system

Combining grant, acknowledgement, and rate control commands