The Directv Group, Inc.

Hughes Electronics Corporation

Khalid Karimullah

Lin-Nan Lee

Feng-Wen Sun

Jian Song

Kamran Etemad

Stanley Edward Kay

Dong-Jye Shyy

Cathy Zatloukal

A system and method for transmitting wideband signals via a radio communication system adapted for transmitting narrow-band signals is described. A base station is used to transmit and receive a plurality of relatively narrow-band and a plurality of relatively wideband signals. The electromagnetic spectrum available to the plurality of narrow-band signals is selectively shared with the electromagnetic spectrum available to the wideband signals by systematically separating the orthogonal codes and the carrier frequencies used for transmission. The prefixes of the orthogonal codes are preferably mutually exclusive and the carrier frequencies are preferably separated by an offset. The offset may be substantially equal to an integer multiple of the narrow-band signal's chip rate. Alternatively, the offset may be substantially equal to an odd multiple of one half the narrow-band signal's chip rate in which case every other bit of the orthogonally encoded data is inverted.

Method and apparatus for orthogonally overlaying variable chip rate spread spectrum signals

An approach is provided for supporting transmission in a multi-input-multi-output (MIMO) communication system including a plurality of terminals. A preamble portion of a frame is transmitted by a multiple transmit antennas of a hub using Orthogonal Frequency Division Multiplexing (OFDM) to the terminals over a channel, wherein each of the terminals determines a characteristic of the channel with respect to the transmit antennas as feedback information. The hub receives the feedback information from the terminals. The hub selects, according to the feedback information, a subset of the antennas for transmission of a remaining portion of the frame to the terminal.

Method and system for providing multi-input-multi-output (MIMO) downlink transmission

A method and apparatus for encoding data for transmission in a communication system provides increased efficiency in bandwidth utilization through higher data rates, lower error rates, lower power levels, and/or increased capacity. A set of orthogonal codes is partitioned into subsets. The data to be transmitted is partitioned into packets of bit sequences, each of which is mapped to an orthogonal code in an assigned subset. The number of members in a particular subset is determined by the relative transmission requirements of the data signal the subset will be used to encode.

Method and apparatus for encoding data for transmission in a communication system

A communication system is used to transmit and receive data on a plurality of relatively narrow-band signals and wideband signals. The two signal types share a common electromagnetic spectrum by employing spreading gain and maintaining orthogonality between simultaneously transmitted wideband and narrow-band signals. Signal orthogonality is maintained by selectively choosing orthogonal codes and aligning or spacing a wideband carrier frequency with respect to the narrow-band carrier frequencies in accordance with the ratio of the wideband to the narrow-band chip frequencies. A pilot signal is preferably transmitted contemporaneously with the transmission of the first spread signal, and a control date signal, associated with a plurality of users on the first bandwidth, is transmitted on a common control channel using a single Walsh code that is shared by a plurality of users in a TDMA protocol.

Method for transmitting wideband signals via a communication system adapted for narrow-band signal transmission

A system and method for transmitting wideband signals via a radio communication system adapted for transmitting narrow-band signals is described. A base station is used to transmit and receive a plurality of relatively narrow-band and a plurality of relatively wideband signals. The electromagnetic spectrum available to the plurality of narrow-band signals is selectively shared with the electromagnetic spectrum available to the wideband signals by systematically separating the orthogonal codes and the carrier frequencies used for transmission. The prefixes of the orthogonal codes are preferably mutually exclusive and the carrier frequencies-are preferably separated by an offset. The offset may be substantially equal to an integer multiple of the narrow-band signal's chip rate. Alternatively, the offset may be substantially equal to an odd multiple of one half the narrow-band signal's chip rate in which case every other bit of the orthogonally encoded data is inverted.

A system and method where a data transmitter retransmits data frames to a receiver for combination with previously transmitted data frames that were received with errors to increase gain at the receiver. The data transmitter receives a retransmission request from the receiver and retransmits a particular data frame without a signaling message. The receiver compares the retransmitted data frame to other data frames stored in a buffer to determine the likelihood of a match between the transmitted data frame and a buffered data frame. When the likelihood of a match exceeds at least one predetermined threshold, the receiver combines the retransmitted data frame with the matching data frame. If the likelihood of a match is below any of the predetermined thresholds, the receiver stores either the combined data frame, or the retransmitted and matching data frame, depending on which threshold is not exceeded, and sends another retransmission request.

System and method for transmitting data in frame format using an R-Rake retransmission technique with blind identification of data frames

A system and method for retransmitting data frames, which were inadequately received by a receiver, back to the receiver to increase receiver gain. Upon receiving a retransmission request from the receiver, the data transmitter retransmits a particular data frame to the receiver without transmitting a signaling message, and the receiver compares it to other data frames stored in a buffer. When a match is believed to exist, the receiver combines the retransmitted data frame with the matching data frame. Based on the result of a cyclic redundant code (CRC) check performed on the combined data frame, the receiver either provides the combined data frame to a higher layer in the receiver, or stores either the combined data frame, or the retransmitted and potentially matching data frame, in the buffer, depending on a confidence in the potential match, and sends another retransmission request to the transmitter to again retransmit the data frame and the above process is repeated.

A system and method for optimizing random access control, and for optimizing transmission efficiency of data packets over reverse common channels between access terminals and a base station, in a wireless communications system. In the communications system, at least one of the access terminals is adapted to transmit at least a portion of an access data packet to the base station, and the base station is adapted to receive the portion of the access data packet and, in response, to transmit a message for receipt by the plurality of access terminals which indicates receipt of the access data packet portion by the base station and identifies the access terminal from which said access data packet portion is received. The message can control the other access terminals to refrain from transmitting an access data packet, while indicating receipt of the access data packet portion to the certain access terminal from which the access data packet portion had been transmitted. The base station can also provide power control signals to control transmission power of that certain access terminal, and to control that certain access terminal to transmit over certain reverse channels. Accordingly, interference between access data packets being transmitted by multiple access terminals and being received in the same time slot by a base station in a wireless communications system can also be minimized.

SYSTEM AND METHOD FOR USING INHIBIT SENSE MULTIPLE ACCESS (ISMA) PROTOCOL AND A CAPTURE MESSAGE TO OPTIMIZE RANDOM ACCESS CONTROL AND DATA PACKET COMMUNICATION BETWEEN ACCESS TERMINALS AND A BASE STATION OVER A WIRELESS REVERSE COMMON CHANNEL

A communication system is used to transmit and receive a plurality of relatively narrow-band signals and wideband signals. The two signal types share a common electromagnetic spectrum by employing spreading gain and maintaining orthogonality between simultaneously transmitted wideband and narrow-band signals. Signal orthogonality is maintained by selectively choosing orthogonal codes and aligning or spacing a wideband carrier frequency with respect to the narrow-band carrier frequencies in accordance with the ratio of the wideband to the narrow-band chip frequencies. A pilot signal is preferably transmitted contemporaneously with the transmission of the first spreaded signal, and a control data signal, associated with a plurality of users on the first bandwidth, is transmitted on a common control channel using a single Walsh code that is shared by a plurality of users in a TDMA protocol. Further, if the length of the message intended for transmission by the wideband transceivers is below a message length threshold, the message can be transmitted using a common access channel shared by the wideband transceivers. Still further, by adapting the data transmission rate, in response to the data error rate and transmitter power level, the transmission range and/or the data transmission rate can be optimized.

Growing community of inventors

Olney, MD, United States of America

Khalid Karimullah