Abstract: A method and system that enables faster acquisition of the forward link signal of a target base station in a mixed network of synchronous and asynchronous base stations is disclosed. The serving base station transmits in a neighbor list an estimated timing error 417 between the serving base station and a target base station. By utilizing the timing information, a mobile station estimates the relative time offset 408 between forward link signals received from the serving base station and signals received from the target base station. Timing information acquired during handoff enables accurate updating of the estimated timing error 417 subsequently transmitted in the neighbor lists by the base stations.

Abstract: A method and apparatus for controlling transmission power levels in a mobile communication system. The method provides for a closed-loop power control method. A mobile station provides information on the quality of the signal received from the base station, and the base station responds by adjusting the power allocated to that user in a shared base station signal. The transmission power is adjusted initially by a large increment and then ramped down at an increasingly decreasing rate. The mobile station also provides information to the base station as to its relative velocity and the base station adjusts its transmission power in accordance with this velocity information.

Abstract: A method and system for generating forward link channels in a synchronous CDMA base station having a pilot pseudonoise (PN) sequence with a pilot PN sequence offset. In one embodiment the method includes the steps of generating a sync channel including a sync channel message; generating an identification channel including at least the pilot PN sequence offset; and orthogonalizing the sync channel and the identification channel. The identification channel and the sync channel are both transmitted. However, the mobile station may get the pilot PN offset from the identification channel quickly, rather than having to demodulate the entire sync channel message. The identification channel may further include an indication of the phase of the pilot PN sequence, and the epoch of the pilot PN sequence. In one embodiment, the method includes encoding the identification channel using a Golay code.

Abstract: A demultiplexer for channel interleaving in communications systems with multiple carriers and/or transmitter diversity includes a distribution module that distributes data bits in succession to successive transmitter antennas, and a switching module coupled to the distribution module. The distribution module routes one data bit to each antenna such that no data bit is routed to the same antenna as the previous data bit. The switching module controls the distribution module to skip an antenna in the routing process once each time a predefined number of data bits has been routed. Alternatively, the switching module may control the distribution module to repeat an antenna in the routing process once each time a predefined number of data bits has been routed. The transmitter antennas may, in the alternative, be different carrier frequency bands.

Abstract: A novel and improved method for implementing a high-transmission-rate over-the-air interface is described. A transmit system provides an in-phase channel set and a quadrature-phase channel set. The in-phase channel set is used to provide a complete set of orthogonal medium rate control and traffic channels. The quadrature-phase channel set is used to provide a high-rate supplemental channel and an extended set of medium rate channels that are orthogonal to each other and the original medium rate channels. The high-rate supplemental channel is generated over a set of medium rate channels using a short channel code. The medium rate channel is generated using a set of long channel codes.

Abstract: A method and apparatus provides for efficient data rate control and power control processes by transmitting a primary and a secondary pilot channel associated with a data channel. The primary and secondary pilot channels are used for decoding the data. A ratio of power levels of the primary and secondary pilot channels is based on at least one of the data rate and payload size of the data channel. The power level of the primary pilot channel is maintained independent of at least one of data rate and payload size of the data channel. The power level of the secondary pilot channel may be adjusted based on at least one of data rate and payload size of the data channel.

Abstract: Systems and methods for improving the performance of direct-sequence spread-spectrum communication systems. In one embodiment, a system comprises at least one communication channel that utilizes two different orthogonal spreading codes and corresponding portions of the available orthogonal code space. Portions of the data processed by the communication channel are demultiplexed into different streams and covered with corresponding, different orthogonal spreading codes. The streams covered by the different orthogonal codes are then combined and transmitted via the same communication channel. One embodiment utilizes at least two different Walsh codes of different lengths (+− and ++−−) in order to make use of the three quarters of the Walsh space not utilized by low-rate legacy channels.

Abstract: Systems and techniques for communications wherein a data packet is transmitted over at least one time slot from a transmission site, a value is computed from an initial value and information, the initial value being a function of the number of time slots of the data packet transmission, the value and the information is transmitted from the transmission site, the transmitted value and the information is received at a receiving site, the value from the received information is recalculated, and the number of time slots of the data packet transmission is determined from the calculated and recalculated values.

Abstract: Method and apparatus for high rate code-division multiple access wireless communication is described. Each of a channel encoded data is modulated by an associated code having a small number of pseudo-noise spreading chips per orthogonal waveform period, thus producing a set of streams of modulated symbols. Each of the set of streams of modulated symbols is then gain adjusted, and combined to yield two streams of combined symbols. The combination is the set of streams is carried out to reduce a peak-to-average ratio of the transmission. The resulting two combined symbol streams are modulated by a complex multiplyer using a user long code and a pseudorandom spreading code (PN code) and upconverted for transmission.

Abstract: A method and apparatus for providing diversity transmissions to a mobile unit from a transmitting station having at least first and second antennas by repeatedly switching between the two antennas during the transmission of information to the receiving unit. Message information is transmitted from the first antenna in the transmitting station to the receiving unit. After the start of the transmission of the message information from the first antenna, transmission of the message information from the first antenna to the receiving unit terminates and transmission of the message information from the second antenna in the transmitting station to the receiving unit is initiated. Some time after transmission of the message information from second antenna is initiated, the transmission of the message information from the second antenna to the receiving unit terminates and transmission of the message information from the first antenna in the transmitting station to the receiving unit is initiated.

Abstract: Techniques for efficient signaling to a plurality of mobile stations are disclosed. In one embodiment, each of a plurality of symbol streams are encoded with one of a plurality of covering sequences, the covered symbol streams are combined to form a Code Division Multiplexed (CDM) signal, and the CDM signal is further covered by another covering sequence for code division multiplexing with one or more additional signals for transmission to a remote station. In another embodiment, a plurality of CDM signals are formed from the covered symbol streams, and the plurality of CDM signals are Time Division Multiplexed (TDM) prior to the further covering. In other embodiments, decovering and demultiplexing is performed to recover one or more of the symbol streams. Various other aspects are also presented.

Abstract: A method for coherent estimation of the traffic-to-pilot energy ratio is presented. A received preamble is decoded, and then re-encoded. The received preamble is then multiplied by the re-encoded preamble. The results are summed, squared, and then divided by a pilot energy value. In another method, a message carrying energy information can be inserted between a subpacket preamble and a subpacket.

Abstract: Demodulation of a received high rate CDMA wireless signal is obtained by filtering a complex received signal to provide a complex pilot filter signal. The complex pilot filter signal is then use to phase-adjust a set of demodulated subscriber channel signals.

Abstract: In an orthogonal frequency division multiplexing (OFDM) system which uses an outer Reed-Solomon encoder and interleaver an inner convolutional encoder, after the inner convolutional encoding the data bits are interleaved, and then grouped into symbols, each symbol having “m” bits. After grouping, the symbols are mapped to a complex plane using quadrature amplitude modulation (QAM). Thus, bits, not symbols, are interleaved by the inner interleaver. A receiver performs a soft decision regarding the value of each bit in each complex QAM symbol received.

Abstract: A method for coherent estimation of the traffic-to-pilot energy ratio is presented. A received preamble is decoded, and then re-encoded. The received preamble is then multiplied by the re-encoded preamble. The results are summed, squared, and then divided by a pilot energy value. In another method, a message carrying energy information can be inserted between a subpacket preamble and a subpacket.

Abstract: A method for minimizing search time and disruption of current service on an originating frequency during a frequency search excursion to a target frequency as part of an inter-frequency hard handoff between cells on different RF CDMA channels. Disruption of service on the current frequency during the frequency search excursion to the target frequency is minimized by increasing the amount of power allocated to other symbols of two consecutive frames impacted by the search excursion as a function of the search excursion time. The mobile station tunes to a target frequency and collects chip samples, which are stored in a memory buffer. The mobile station returns to the originating frequency to process the collected samples.

Abstract: An efficient retransmission of data using symbol accumulation wherein the packet received in error is retransmitted at a lower energy-per-bit level concurrently in the same frame with the new packet. The destination device receives the data transmission and retransmission, demodulate the signal, and separates the received data into the new and retransmitted packet. The destination device then accumulates the energy of the retransmitted packet with the energy already accumulated for the packet received in error and decodes the accumulated packet. The accumulation of the additional energy provided by the subsequent retransmissions improves the probability of a correct decoding. The throughput rate can be improved since the packet received in error is retransmitted concurrently with the transmission of the new data packet. The capacity is maximized since the retransmission of the packet received in error is at a lower energy level than that of the new packet.

Abstract: A method and apparatus for demodulation in high rate CDMA wireless communication is described. In a described high rate CDMA wireless system, a transmitter forms a set of individually gain adjusted subscriber channels using a set of orthogonal subchannel codes having a small number of PN spreading chips per orthogonal waveform period. An illustrative high rate CDMA wireless system uses Walsh codes, each having a duration of fewer than sixty-four chips per orthogonal waveform period. A receiver demodulates each of the subscriber channels using the same orthogonal subchannel codes.

Abstract: Rather than attaching a preamble to a data traffic subpacket, a preamble channel is transmitted along with a traffic channel. An ARQ channel is established on the reverse link in response to a received transmission on the preamble channel and the traffic channel. In accordance with the type of ARQ signal received or the lack of receipt thereof, a scheduling element in the base station alters an already existing transmission schedule for transmitting old data traffic or new data traffic.

Abstract: A method and apparatus for high rate CDMA wireless communication is described. Variable data rates are generated using a set of different encoder, interleaver, and symbol repetition configurations. An encoder associated with each rate generates a variable number of symbols during each frame period. This variable number of symbols is repeated as necessary to form a constant number of symbols equal to a fixed number of symbols that can be then repeated a fixed number of repetitions before transmission. Where the constant number of symbols is not an integer multiple of the variable number of symbols for a particular rate, a subset of the variable number of symbols is repeated to fill in the remaining symbols necessary to equal the constant number of symbols.