Abstract: A special coding scheme is disclosed for more effectively acquiring a long code and frame timing during a cell search in a CDMA communications system. A code set of length M Q-ary code words including symbols from a set of Q short codes is defined with certain properties. The primary property to be satisfied is that no cyclic shift of a code word yields a valid code word. The other properties to be satisfied are that there is a one-to-one mapping between a long code message and a valid code word, and a decoder should be able to find both the random shift (thereby implicitly finding the frame timing) and the transmitted code word (i.e., its associated long code indication message) in the presence of interference and noise, with some degree of accuracy and reasonable complexity.

Abstract: In a communications system, communications resources are allocated in a dynamic, “as needed” fashion. No explicit signaling is needed to exchange information pertaining specifically to an allocated communications resource. Instead, resources are implicitly allocated by using one or more parameters known to both the radio access network and mobile station that are more or less unique to the mobile station. Such parameters are used to generate or address a communications resource for use by the mobile station. The parameters might, for example, be information readily acquired or communicated as a result of a synchronization procedure, a mobile station registration procedure, a mobile station access procedure, a paging procedure, etc.

Abstract: A method is disclosed for processing mobile-originated random access requests in a mobile telecommunications system that randomly selects new signatures for re-transmissions in the event that collisions have occurred. As such, the random access re-transmissions are randomized over the signature domain instead of just over the time domain. Consequently, the disclosed invention significantly shortens random access delays caused by collisions or erroneous arrivals at base station receivers, and also significantly reduces the interval between random access re-transmissions.

Abstract: A method for improving the performance of a random access communications system in a variable radio environment is disclosed, whereby at least one valid set of burst signatures is used for transmission by one or more mobile stations. Each set includes at least one signature with a different signature-length than the signatures in other sets. The different signature-lengths can be optimized for the operational environments involved (e.g., longer signatures for slower-moving mobile stations, and shorter signatures for high-speed mobile stations). Alternatively, at least one differentially-encoded signature is used for random access transmissions, in order to reduce the radio channel's sensitivity to large doppler spreads and frequency errors.

Abstract: A method and system are disclosed for facilitating the timing (e.g., the known relative timing differences) of base stations (BSs) in asynchronous CDMA mobile communications systems. A plurality of mobile stations (MSs) measure the relative time differences between various pairs of BSs, and these measurements are stored by the BSs. A source BS sends to an MS, in a neighbor list message, estimates of the relative time difference between the source BS and each of the BSs on the neighboring cell list. Each BS on the list can maintain a relative time difference estimate table, which can be updated continuously from the reports received from MSs. Subsequently, the BSs can send entries from this table to the MS in the neighbor list message. Using this novel technique, the BSs have known relative timing differences. Consequently, when the MS initiates a cell-search for a candidate BS, the MS already has an estimate of the timing of that BS as compared to its source BS.

Abstract: A novel format is provided for an uplink common physical channel in a random access mobile communications system, whereby a mobile station transmits a first packet including a predetermined signature pattern in parallel with a second packet including the data part of the random access request. Consequently, in addition to its attendant advantages, the signature part of a random access request can also function as a Pilot by providing additional energy for channel estimation during the data part of the request, while reducing the amount of overhead signalling involved. This additional energy is especially useful for ensuring sufficiently high quality coherent detection of the data part in a rapidly varying radio channel environment.

Abstract: A special coding scheme is disclosed for more effectively acquiring a long code and frame timing during a cell search in a CDMA communications system. A code set of length M Q-ary code words including symbols from a set of Q short codes is defined with certain properties. The primary property to be satisfied is that no cyclic shift of a code word yields a valid code word. The other properties to be satisfied are that there is a one-to-one mapping between a long code message and a valid code word, and a decoder should be able to find both the random shift (thereby implicitly finding the frame timing) and the transmitted code word (i.e., its associated long code indication message) in the presence of interference and noise, with some degree of accuracy and reasonable complexity.

Abstract: A special coding scheme is disclosed for more effectively acquiring a long code and frame timing during a cell search in a CDMA communications system. A code set of length M Q-ary code words including symbols from a set of Q short codes is defined with certain properties. The primary property to be satisfied is that no cyclic shift of a code word yields a valid code word. The other properties to be satisfied are that there is a one-to-one mapping between a long code message and a valid code word, and a decoder should be able to find both the random shift (thereby implicitly finding the frame timing) and the transmitted code word (i.e., its associated long code indication message) in the presence of interference and noise, with some degree of accuracy and reasonable complexity.

Abstract: A method and system for use in determining the position of a mobile terminal in a CDMA mobile communications system is disclosed, whereby a different than usual spreading code is used when TOA measurements are being performed, but information is allowed to be transmitted while those TOA measurements are being performed. In one embodiment, the length of the different spreading codes used is equal to one symbol length. In a second embodiment, a mobile terminal uses a long spreading code and short spreading code prior to making TOA measurements. When TOA measurements are to be made, the serving base station orders the mobile terminal to change the spreading code by terminating the use of the long code and continuing use of the short code. Alternatively, when the TOA measurements are to be made, the serving base station orders the mobile terminal to substitute a second, predetermined short code for the long code being used, and to continue use of the first short code.

Abstract: With respect to a direct sequence, code division multiple access spread spectrum transmitter, symbol information relating to dedicated/common channels (such as the traffic or control channels) is spread to generate a plurality of corresponding dedicated/common channel intermediate signals. These intermediate signals are then summed to generate an output signal that is scrambled by a selected scrambling code. Symbol information relating to acquisition-related channels (such as synchronization information or the pilot or long code group code channels) is also spread to generate a plurality of corresponding acquisition-related intermediate signals. These acquisition-related intermediate signals are then selectively added to the scrambled output signal producing a downlink signal for multi-channel transmission over a communications medium sharing one transmission communications frequency.

Abstract: Each transmission frame within a spread spectrum communications system relating to synchronization code transmission is divided into a plurality of slots. Each of the slots includes a primary (pilot) code c.sub.p and a secondary (combined) code c.sub.s/lci that includes information identifying or indicative of both a frame timing and a scrambling code for synchronization. This information concerning frame timing and scrambling code may be encoded in the combined code c.sub.s/lci itself, as well as in the modulation values of the sequences of plural combined codes within a frame. Alternatively, the information is encoded in the sequence of plural combined codes c.sub.s/lci transmitted in each frame, as well as in the modulated values of the sequences of plural combined codes within a frame. As yet another alternative, the information is encoded in the timing of the combined code c.sub.s/lci transmission within each slot of the frame relative to its associated primary code c.sub.p.

Abstract: In a digital radio communication system in which information is transmitted and received in time slots and some bits of each received audio frame is interleaved over at least two time slots and other bits in each audio frame at are non-interleaved, bad received audio frames are detected by detecting possible bit errors in a channel encoded non-interleaved bit sequence in each received time slot. If bit errors have been detected in this bit sequence a bad received frame is indicated.

Abstract: The present invention discloses a method for transmitting a plurality of information streams having variable data rates. A plurality of information streams are multiplexed together into a common information frame. The information is channel encoded and multiplexed with a number of overhead bits including encoding information on the multiplexed frame. The multiplexed frame is then demultiplexed into at least one channel frames that are each transmitted over a separate code channel such that the first code channel always includes the overhead bit data.

Abstract: A method and system for transmitting signals using unequal error protection (UEP). According to the method, symbols having a higher level of coding protection are detected and decoded first, soft reliability information is generated, and then the previously detected symbols and soft reliability information are used to detect and decode symbols having the next lower level of coding protection. The symbols having lower levels of coding protection benefit from the decoding of all previous classes of symbols. Data symbols can be interleaved to further enhance system performance.

Abstract: A method and system for transmitting background noise information on a packet reservation multiple access radio channel. In the method and system, relative priorities are assigned to background noise data transmissions and speech data, or other data traffic, transmissions. The priorities are assigned so that the effect of background noise data transmissions on the delays and quality of speech data, or other data traffic, transmissions within the system is reduced.

Abstract: In a digital signal transmission system, a receiver receives a signal, wherein the signal bandwidth of the system exceeds the system symbol rate. A correlation and sampling circuit receives a baseband signal, samples the signal eight times per symbol time, correlates, generates a channel estimate and down-samples the sampled signal to form an observed signal. This signal is filtered in a prefilter, whose output is sampled at symbol rate and the obtained signal is delivered to a channel equalizer which performs a viterbi algorithm with non-quadratic metric calculation and generates estimated symbols. A channel estimation filter receives a symbol sequence which contains alternate zero-value symbols and the estimated symbols and generates an estimated signal. An error signal is generated and used to adapt the channel estimate and also to generate weight factors. The coefficients of the prefilter are generated as a function of the channel estimate and the weight factors.

Abstract: In a digital time-shared transmission system, a receiver receives a signal whose symbol rate is lower than the channel bandwidth of the system. A correlating and sampling circuit receives a baseband signal, samples the signal a number of times with each symbol time, performs channel correlation, generates a channel estimate and samples down the once sampled signal to an observed signal with two values for each symbol time. A channel equalizer executes a fractional viterbi algorithm which utilizes two delta-metric values for each state transition and generates estimated symbols. A channel estimating filter receives a symbol sequence of alternating zero-value symbols and the estimated symbols and generates an estimated signal. The channel estimating filter is adapted with the aid of an error signal and the filter delivers a channel estimate to the channel equalizer.

Abstract: A low complexity model based channel estimator is disclosed for use by a receiver in Rayleigh fading environments. The receiver contains at least one channel state estimator which uses an auto regressive model for channel variations. The channel state estimates are initialized by using at least preliminarily detected symbols. The receiver also contains a data detector which uses the received signal and the channel estimate, or a function thereof, delivered by at least one channel estimator to detect the transmitted symbols.

Abstract: In a digital signal transmission system, a receiver receives a signal, wherein the signal bandwidth of the system exceeds the system symbol rate. A correlation and sampling circuit receives a baseband signal, samples the signal eight times per symbol time, correlates, generates a channel estimate and down-samples the sampled signal to form an observed signal. This signal is filtered in a prefilter, whose output is sampled at symbol rate and the obtained signal is delivered to a channel equalizer which performs a viterbi algorithm with non-quadratic metric calculation and generates estimated symbols. A channel estimation filter receives a symbol sequence which contains alternate zero-value symbols and the estimated symbols and generates an estimated signal. An error signal is generated and used to adapt the channel estimate and also to generate weight factors. The coefficients of the prefilter are generated as a function of the channel estimate and the weight factors.

Abstract: A method for improving time synchronization of digital data signals in receivers by using more than one known data sequence to provide a plurality of timing recovery functions and based on these, one or more optimal sampling points. By using existing data sequences in each frame, the disclosed method provides improved time synchronization without increasing transmission overhead.