Abstract: A multiple-input multiple-output (MIMO) receiver includes a MIMO decoder, a pre-scaling unit, a demapper, and a post-scaling unit. The MIMO decoder performs a MIMO decoding on received signals to decouple a plurality of symbols transmitted via a plurality of data streams. Both pre-demapping scaling and post-demapping scaling are performed to improve the performance of the receiver. A pre-scaling coefficient is applied to the symbols by the pre-scaling unit to generate pre-scaled symbols. The pre-scaled symbols are converted to soft bits by the demapper. The post-scaling unit then applies a post-scaling coefficient to the soft bits. The post-scaling coefficient is a signal-to-interference and noise ratio (SINR). Cross interference is taken into account in post-demapping scaling to obtain more accurate soft bits for subsequent decoding. The present invention is applicable to both a multi-carrier system, (such as orthogonal frequency division multiplexing (OFDM)), and a single carrier system.

Abstract: A simplified QAM signal constellation symbol-wise remapping scheme for data packet retransmissions to improve performance at a high coding rate. The simplified QAM signal constellation symbol-wise remapping scheme takes advantage of the separate I and Q labeling bits in a QAM signal to reduce the complexity of a receiving node. A method for adaptive switching between bit-wise and symbol-wise constellation remapping for data packet transmissions according to channel coding rate to achieve optimum performance across the range of channel coding rates.

Abstract: A wireless communication method and system for performing bit-interleaved coded modulation and iterative decoding. The system includes a transmitter and a receiver. The transmitter encodes incoming bits to generate coded bits, punctures the coded bits in accordance with a predetermined puncturing pattern to generate surviving channel bits and stolen bits and interleaves the surviving bits into interleaved surviving bits. The interleaved surviving bits are mapped to channel symbols and the stolen bits are interleaved to generate interleaved stolen bits. At least one of a plurality of antennas is selected to transmit the channel symbols based on the value of the interleaved stolen bits. The receiver receives the transmitted channel symbols, estimates a posteriori probability for both the channel symbols and the stolen bits, and retrieves information of the stolen bits by determining the selected antenna used to transmit the channel symbols.

Abstract: A method and apparatus for implementing hybrid automatic repeat request (H-ARQ) in a multiple-input multiple-output (MIMO) wireless communication system are disclosed. A transmitter transmits at least two data packets via two or more antennas. If at least one of the data packets is not successfully transmitted, the transmitter retransmits the data packets while rearranging the data packets in an orthogonal spreading manner. Alternatively, the transmitter may retransmit only the unsuccessfully transmitted data packet along with a new data packet which replaces a successfully transmitted data packet. The unsuccessfully transmitted data packet may simply be repeated without changing its format. When only the unsuccessfully transmitted data packet is retransmitted along with the new data packet, the transmissions may be combined to recover the retransmitted data packet and the new data packet simultaneously.

Abstract: One or more quality indicators are established at a first communication device having antenna elements. The quality indicators indicate a quality of one or more communication links between the first communication device and one or more second communication devices. A modification is determined according to the quality indicators, where the modification describes at least one adjustment of one or more modulation features. At least some of a set of signals are modulated in accordance with the modification, where a signal is associated with an antenna element. The set of signals is sent from the antenna elements to yield a transmitted signal.

Abstract: A method and apparatus for performing uplink transmission in a multiple-input multiple-output (MIMO) single carrier frequency division multiple access (SC-FDMA) system are disclosed. At a wireless transmit/receive unit (WTRU), input data is encoded and parsed into a plurality of data streams. After modulation and Fourier transform, one of transmit beamforming, space time coding (STC) and spatial multiplexing is selectively performed based on channel state information. Symbols are then mapped to subcarriers and transmitted via antennas. The STC may be space frequency block coding (SFBC) or space time block coding (STBC). Per antenna rate control may be performed on each data stream based on the channel state information. At a Node-B, MIMO decoding may be performed based on one of minimum mean square error (MMSE) decoding, MMSE-successive interference cancellation (SIC) decoding and maximum likelihood (ML) decoding. Space time decoding may be performed if STC is performed at the WTRU.

Abstract: A method and apparatus for selecting a beam combination of beam switched antennas in a multiple-input multiple-output (MIMO) wireless communication system including a first node and a second node. The first node sends a plurality of modulation and coding scheme (MCS) requests to the second node. Each of the plurality of MCS requests is sent using a particular beam combination. The second node receives the MCS requests and generates MCS feedback signals for each of the MCS requests. Each MCS feedback signal includes an MCS recommendation for the particular beam. The first node selects a beam combination for communicating with the second node based on the MCS recommendations.

Abstract: Communication is performed for a first communication device having a set of antenna elements. A quality-indication signal is received from a second communication device (e.g., a basestation). A complex weighting is calculated based on the quality-indication signal. A pre-transmission signal is modified based on the complex weighting to produce a set of modified-pre-transmission signals. Each modified pre-transmission signal from the set of modified-pre-transmission signals is uniquely associated with an antenna element from the set of antenna elements. The set of modified-pre-transmission signals is sent from the set of antenna elements to produce a transmitted signal. The complex weighting is associated with a total power of the transmitted power and at least one from a phase rotation and a power ratio associated with each antenna element from the set of antenna elements.

Abstract: Combining signals includes receiving a plurality of groups of signals at a plurality of antennas at a mobile device, where each group of signals includes a plurality of signals, and each signal includes a time slot. The following is repeated for each group of signals of the plurality of groups of signals. An adjustment associated with a time slot of each signal is set. Each signal of the group of signals is adjusted at the time slot in accordance with the adjustment associated with the time slot. A signal quality associated with each time slot of each signal of the group of signals is established, and an optimal adjustment in accordance with the signal qualities is determined. The signals are adjusted in accordance with the optimal adjustment.

Abstract: A wireless communications device includes an encoder having an input for receiving an input symbol, and generates based upon the input symbol a channel symbol and an antenna control symbol. At least one transmitter is coupled to the encoder for receiving the channel symbol. An antenna switch is coupled to the encoder for receiving the antenna control symbol, and to the at least one transmitter for receiving the channel symbol to be transmitted. An antenna array is coupled to the antenna switch and includes N antenna elements, with N?2. The antenna switch selects less than N antenna elements based upon the antenna control symbol for transmitting the channel symbol.

Abstract: A method and apparatus for selecting a beam combination of multiple-input multiple-output (MIMO) antennas are disclosed. A wireless transmit/receive unit (WTRUs) includes a plurality of antennas to generate a plurality of beams for supporting MIMO. At least one antenna is configured to generate multiple beams, such that various beam combinations can be produced and a desired beam combination selected for conducting wireless communication with another WTRU. A quality metric is measured with respect to each or subset of the possible beam combinations. A desired beam combination for MIMO transmission and reception is selected based on the quality metric measurements.

Abstract: A transmitter in an OFDM-MIMO wireless communication system uses multiple antennas to transmit each data stream. Before the coded binary bits are mapped into channel symbols, they are divided into two groups. One group is mapped to a channel symbol as in a conventional system. Another group of binary bits is used to generate a spatial mapping index. The spatial mapping index determines which antenna is to be used to transmit the channel symbol for each subcarrier. Effectively, information bits are jointly represented by a combination of a channel symbol and an antenna that transmits the channel symbol. Therefore, to achieve the same data rate, a smaller signal constellation is required. In addition, spatial diversity can be achieved which is similar to traditional switching diversity. The number of non-zero subcarriers is reduced by half on average, which results in a lower peak to average ratio than conventional OFDM systems.

Abstract: An apparatus and a method for improving packet transmission and reducing latency in VoIP over WLAN using switched beam antennas having multiple directional antenna beams are disclosed. In an access point having a switched beam antenna, or other smart antenna system, the present invention extends the coverage area of an access point for authentication and association of a new WTRU, extends the access points coverage area during in session transmissions with a WTRU, and adjusts data rates. The method also controls Contention Period (CP)/Contention Free Period (CFP) timing amongst beams emanating from an access point having a switched beam antenna, or other smart antenna system. Fast diversity switching, frame level switching, lowered data rates, and scanning multiple directional antenna beams for the optimum transmission beam are disclosed to improve beam selection and packet transmission.

Abstract: A wireless communication system includes a transmitter comprising a serial-to-parallel converter for converting serial data bits to a parallel bit stream, a signal mapper coupled to the serial-to-parallel converter and an antenna selector coupled to the serial-to-parallel converter. The signal mapper receives as input a first group of bits from the parallel bit stream, and maps the first group of bits to a channel symbol. The antenna selector receives as input a second group of bits from the parallel bit stream. A transmit antenna array is coupled to the antenna selector and to the signal mapper. The transmit antenna array generates a plurality of transmit antenna patterns with one of the transmit antenna patterns being selected for transmitting the channel symbol based upon the second group of bits from the antenna selector.

Abstract: One or more quality indicators are established at a first communication device having antenna elements. The quality indicators indicate a quality of one or more communication links between the first communication device and one or more second communication devices. A modification is determined according to the quality indicators, where the modification describes at least one adjustment of one or more modulation features. A time boundary indicator indicating a boundary of a time period is received. At least some of a set of signals are modulated in accordance with the modification and in response to the time boundary indicator, where a signal is associated with an antenna element. The set of signals is sent from the antenna elements to yield a transmitted signal.

Abstract: Determining a power control group boundary includes receiving a plurality of samples having power control groups, where each power control group corresponds to a time period. The following are repeated for a predetermined number of iterations: a window is set at a point of a sample; a number of power control bits within the window at the point is determined; and the window is moved to a point of a next sample. A point at which the window has the largest number of power control bits is identified. A power control group boundary is determined in accordance with the window at the identified point.

Abstract: A communications device with a switched beam antenna operates in a wireless local area network (WLAN) that includes a plurality of transmitters. The switched beam antenna generates a plurality of antenna beams. A method for operating the communications device includes receiving signals from the plurality of transmitters operating within the WLAN, identifying the received signals comprising medium access control (MAC) information, and determining a quality metric for each received signal comprising MAC information. A transmitter is selected based on the quality metrics. The antenna beams are scanned for receiving from the selected transmitter the signals comprising MAC information. A quality metric associated with each scanned antenna beam is determined. One of the scanned antenna beams is then selected for communicating with the selected transmitter based on the quality metrics.

Abstract: A method for steering a smart antenna in a wireless communication system begins by selecting a beam steering criterion. The antenna is switched to one of a plurality of measurement positions and link quality metrics are measured at each measurement position. The steering criterion are optimized based on the measured metrics, and the antenna is steered to the position providing the optimized metrics.

Abstract: One or more quality indicators are established at a first communication device having antenna elements. The quality indicators indicate a quality of one or more communication links between the first communication device and one or more second communication devices. A modification is determined according to the quality indicators, where the modification describes at least one adjustment of one or more modulation features. At least some of a set of signals are modulated in accordance with the modification, where a signal is associated with an antenna element. The set of signals is sent from the antenna elements to yield a transmitted signal.

Abstract: Adjusting a signal includes receiving signals and quality indicators at an adjuster. The quality indicators include as least one of a power control group boundary signal, a power control group index, a PN code per active finger, a reverse power control bit per active finger, an energy per chip over noise power spectral density ratio per active finger, channel estimates I/Q per active finger, an energy per bit over noise power spectral density, a transmit AGC signal, a total receive power, and any combination of the preceding. A signal adjustment is calculated according to the quality indicators, and the signals are adjusted according to the signal adjustment to yield adjusted signals.