Abstract: A method and an apparatus for waveform quality measurement are disclosed. An actual signal, representing a waveform channelized both in time and in code is generated by, e.g., an exemplary HDR communication system. Test equipment generates an ideal waveform corresponding to the actual waveform. The test equipment then generates an estimate of offsets between parameters of the actual waveform and the ideal waveform, and the offsets are used to compensate the actual waveform. The test equipment then evaluates various waveform quality measurements utilizing the compensated actual waveform and the corresponding ideal waveform. Definitions of the various waveform quality measurements as well as conceptual and practical examples of processing of the actual waveform and the corresponding ideal waveform by the test equipment are disclosed. The disclosed method and apparatus may be extended to any waveform channelized both in time and in code regardless of the equipment that generated the waveform.

Abstract: Techniques to support handover of a terminal from a source base station to a target base station are described. In one design, a determination is made whether a change in personality is requested by the terminal. If the answer is ‘Yes’, then the personality of the terminal may be switched by sending one or more appropriate messages. The connection and RLP for the terminal may be reset due to the change in personality. A buffer of data reported by the source base station as being served to the terminal (e.g., no NAK was sent) may be saved by a BSC/PCF. The buffer of data may be sent to the target base station when handover occurs. New data may thereafter be sent to the target base station. This buffer of duplicate data may avoid both loss of data and retransmission timeout by TCP during the handover.

Abstract: A method and an apparatus for scaling demodulated data symbols contained in a packet to generate scaled log-likelihood ratios for Turbo decoding are disclosed. A packet consists of one or more subpackets depending on the type of packet. Each subpacket is identified by a subpacket identification number. The payload size of the packet and the subpacket identification number may be determined by decoding a reverse rate indicator (RRI) channel. A scale factor which is associated with a specific subpacket identification number and a specific payload size results in a performance measure that is closest to an expected performance measure. The scale factor is used for scaling the demodulated data symbols to generate scaled log-likelihood ratios for Turbo decoding.

Abstract: A variable rate transmission system transmits a variable rate data packet including an accompanying rate indication signal indicative of the transmission rate of the variable data packet. The data packet can be spread using a long pseudonoise (PN) code, the mask of which can be selected in accordance with the transmission rate of the variable rate data packet. A preamble, providing the transmission rate, can be punctured into an outgoing pilot signal. The rate indication signal can be encoded in accordance with a set of orthogonal functions that are part of the indication of the transmission rate of the data packet.

Abstract: Techniques to efficiently attempt acquisition of a packet data system (e.g., an IS-856 system). If a terminal has acquired one or more channels in a voice/data system (e.g., an IS-2000 system), then it can attempt acquisition on channels in the packet data system that are co-located with the acquired channels in the voice/data system. Multiple acquisition modes may be used, and on-going acquisition attempts on the co-located channels may be performed using one acquisition mode at a time in order to reduce power consumption. Acquisition attempts may be performed in a “ping-pong” manner to improve the likelihood of acquisition. For a ping-pong search, an acquisition attempt is made on the most recently acquired channel prior to an acquisition attempt on each of the remaining channels. Received signal strength estimates may also be obtained for selected channels and may be used to determine whether or not to attempt acquisition on these channels.

Abstract: A pilot reference transmission scheme well suited for high data rate wireless communication systems is disclosed. To maximize the amount of interference from transmissions from neighboring transmission sources (e.g., access points or base stations) during the pilot interval, and hence minimize the amount of interference from non-transmitting sources during the data intervals, the pilot references are transmitted in bursts at predetermined time intervals, and the pilot bursts from the access points are synchronized. This results in maximum interference contributions from non-transmitting neighboring access points, facilitating reliable estimation of worst case carrier-to-interference (C/I), and further allows the receiving devices (e.g., access terminals) to easily recognize the bursts as pilot reference. In one embodiment, each access point transmits the pilot bursts at or near its maximum transmit power level and no user-specific data is transmitted during the pilot bursts.

Abstract: Method and apparatus for estimating reverse link loading in a wireless communication system. The reverse link interference is measured and reverse link receiver noise is measured. The reverse link interference is compared to the reverse link receiver noise, for example, by dividing the interference power by the receiver noise power. The reverse link receiver noise can be measured in an orthogonal frequency division multiple access (OFDMA) system by nulling transmission from access terminals within the cell and nearby during a null time and frequency interval. Power measure in the null time and frequency interval is receiver noise power. The reverse link interference can be measure by several means. For example, local null time and frequency intervals can be designated. The access terminals within the cell null their transmissions during the local time and frequency intervals. Access terminals outside the cell continue to transmit during the local time and frequency intervals.

Abstract: A method and an apparatus for quick retransmission of signals in a communication system are disclosed. A transmitting terminal, e.g., a base station, transmits signals in a form of packets to a receiving terminal, e.g., a subscriber station. The receiving terminal determines if the packet was intended for the receiving terminal, and if so, the receiving terminal demodulates the packet. The receiving terminal then computes a quality metric of the packet, and compares the computed quality metric with a quality metric contained in the packet. If the quality metrics match, the packet is declared correctly received, and is forwarded for further processing. If the quality metrics fail to match, the receiving terminal sends a request for retransmission of the packet. The transmitting terminal determines which packet needs to be retransmitted based on the request for retransmission. The transmitting terminal then schedules the packet for retransmission.

Abstract: Methods and apparatus for selecting a serving sector in a high rate data (HDR) communication system are disclosed. An exemplary HDR communication system defines a set of data rates, at which a sector of an Access Point may send data packets to an Access Terminal. The sector is selected by the Access Terminal to achieve the highest data throughput while maintaining a targeted packet error rate. The Access Terminal employs various methods to evaluate quality metrics of forward and reverse links from and to different sectors, and uses the quality metrics to select the sector to send data packets to the Access Terminal.

Abstract: Embodiments disclosed herein relate to methods and systems for providing improved position-location (e.g., time-of-arrival) measurement and enhanced position location in wireless communication systems. In an embodiment, an access point may replace information (e.g., data) transmission by a “known” transmission (or “reference transmission”) at a predetermined time known to access terminals in the corresponding sectors. The access terminals may use the received reference transmission to perform a position-location measurement, and report back the measured information. The access point may also send a reference transmission on demand, e.g., in response to a request from an access terminal in need for a location-based service.

Abstract: A method and system for reverse link transmit beam-forming. One method comprises using a plurality of antennas at an access terminal to wirelessly transmit signals to one or more base stations; receiving an input indicating a reverse link signal quality at the one or more base stations; and adjusting at least one of a gain and a phase of a signal to be transmitted on one or more antennas. The input may be a reverse power control (RPC) value sent from one or more base stations or a measurement of the closed-loop pilot transmit power.

Abstract: A system and method for providing group communication services is disclosed. Each of a plurality of group communication devices coverts media, such as video, audio, image and/or data into data packets suitable for transmission over a data network, such as the Internet. The data packets are selectively transmitted through the data network to a communications manager. The communications manager acts as a configurable switch, allowing communications from any communication device to be selectively routed to the plurality of communication devices based on the types of the communication devices and/or the requests received from the corresponding users. The communications manager further allows users of other communication systems and devices to participate in group communications with each other.

Abstract: Methods and apparatus for estimating a transmission power required for data transmission in a communication system are disclosed. A terminal determines a quality metric of a communication link, over which data are to be transmitted, and modifies the determined quality metric by a quality metric margin. The terminal then estimates the maximum rate of data in accordance with the modified quality metric. Alternatively, the terminal estimates transmission power required for data transmission with a data rate in accordance with the modified quality metric. The quality metric margin may be a pre-determined or dynamically adjusted. The terminal dynamically adjusts the quality metric margin in accordance with a result of comparison of a transmit power corresponding to the estimated maximum rate of data with an actual transmit power used to transmit the data.

Abstract: A communication system including a closed loop power control system. Prior to allowing a handoff to a new base station, the subscriber station verifies that its reverse link signal is being received by the destination base station with sufficient energy. The determination is made based on the received reverse link power control commands from the base station. Moreover, a handoff may be forced when the base station providing the best forward link signal in not receiving the reverse link signal from the subscriber station with sufficient energy.

Abstract: Methods and apparatus to decode encoded data. One method starts and stops turbo decoding depending on channel conditions of a received pilot signal. One method may be used with Hybrid Automatic Repeat Request (H-ARQ).

Abstract: A transmitter directed, distributed receiver using multi-user diversity provided by the distribution of the receiver. Advantage is taken of the uncorrelated variations over time in the condition of communication links between a common transmitter and several users. The greater the variation in the quality of a particular link over time, the greater the increase in total system throughput provided. A scheduler metric (or scheduler metric) represents the instantaneous quality of the communication link between each user and the transmitter with respect to the average quality of the link. Alternatively, the scheduler metric represents the instantaneous channel condition with respect to the average data throughput over that channel. The common transmitting station uses the scheduler metric to directly compare the desirability of granting each channel access with the desirability of granting each other channel access. The users with links that have the greatest scheduler metric are provided access to the channels.

Abstract: 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.

Abstract: Embodiments disclosed herein relate to methods and systems for pilot grouping, route protocols, and scheduling in multi-carrier communication systems. In an embodiment, an access terminal may group a plurality of pilot signals characterized by different frequencies into one or more pilot groups, each pilot grouping being identified by a plurality of parameters (e.g., a PN offset and a group ID). Each pilot group may include pilot signals having substantially the same coverage area. The access terminal may further select a representative pilot signal from each pilot group for pilot strength reporting. The access terminal may also use the pilot grouping for effective set management.

Abstract: 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.

Abstract: A method and system for providing asymmetric modes of operation in multi-carrier wireless communication systems. A method may assign a long code mask (LCM) to an information channel associated with a plurality of forward link carriers to transmit data from an access network to an access terminal; and multiplex the information channel on a reverse link carrier. The information channel may include one of data source channel (DSC), data rate control (DRC) and acknowledgment (ACK) information, and the multiplexing may be code division multiplexing (CDM). The AN may instruct the AT on whether to multiplex the DSC information based on feedback from the AT. The method may further offset the ACK information on the reverse link to reduce the reverse link peak to average, CDM the information channel on an I-branch and on a Q-branch, and transmit the code division multiplexed information channel on the reverse link carrier.