Abstract: A wireless multiple access method allows multiple transmitters to access the same channels so that substantial interference occurs. The transmitters use low rate turbo coding and the receiver uses multi-user detection to separate and decode the transmissions. Different propagation and/or transmission characteristics between the transmitters help to distinguish the transmissions at the receiver. The transmitters may add random variation to their transmission timing, power and/or frequency to assist with decoding.

Abstract: In a bandwidth allocation protocol for a mobile communications network, mobile terminals indicate the total quantity of data awaiting transmission, the maximum delay time of the most urgent portion of the data, and the maximum delay time of the least urgent portion. If a collision occurs between transmission by two mobiles, the mobiles wait for an interval controlled by the network before attempting another contention-based access transmission. The network periodically varies the contention-based access capacity available according to the observed usage level and/or collision rate in the previously allocated contention-based access capacity. The network analyses the forward traffic to individual mobiles and predicts likely return bandwidth requirements.

Abstract: In a bandwidth allocation protocol for a mobile communications network, mobile terminals indicate the total quantity of data awaiting transmission, the maximum delay time of the most urgent portion of the data, and the maximum delay time of the least urgent portion. If a collision occurs between transmission by two mobiles, the mobiles wait for an interval controlled by the network before attempting another contention-based access transmission. The network periodically varies the contention-based access capacity available according to the observed usage level and/or collision rate in the previously allocated contention-based access capacity. The network analyses the forward traffic to individual mobiles and predicts likely return bandwidth requirements.

Abstract: In a wireless communications system, transceivers transmit short bursts to a base station, which determines timing corrections from the time of receipt of the burst and transmits the timing corrections to the respective transceivers. In one aspect, the base station indicates to the transceivers a plurality of time slots, each transceiver selects one of the time slots at random, formats a burst including an indicator of the selected time slot and transmits the burst in that slot. In another aspect, the base station transmits to each transceiver a timing uncertainty value, which determines how the timing correction will be modified by the tranceiver as the interval since last receiving a timing correction increases. Data bursts are transmitted in a format comprising a first unique word, a content field and a second unique word, in that order. The bursts are transmitted in a TDMA channel format which can accommodate both short and long bursts in a block format of constant periodicity.

Abstract: In a bandwidth allocation protocol for a mobile communications network, mobile terminals indicate the total quantity of data awaiting transmission, the maximum delay time of the most urgent portion of the data, and the maximum delay time of the least urgent portion. If a collision occurs between transmission by two mobiles, the mobiles wait for an interval controlled by the network before attempting another contention-based access transmission. The network periodically varies the contention-based access capacity available according to the observed usage level and/or collision rate in the previously allocated contention-based access capacity. The network analyses the forward traffic to individual mobiles and predicts likely return bandwidth requirements.

Abstract: In a bandwidth allocation protocol for a mobile communications network, mobile terminals report their bandwidth requirements to the network, while the network controls the amount of bandwidth that is used by the mobiles in reporting their bandwidth requirements. The mobiles indicate the total quantity of data awaiting transmission, the maximum delay time of the most urgent portion of the data and the maximum delay time of the least urgent portion. If a collision occurs between transmission by two mobiles, the mobiles wait for an interval controlled by the network before attempting another contention-based access transmission. The network periodically varies the contention-based access capacity available according to the observed usage level and/or collision rate in the previously allocated contention-based access capacity. The network analyses the forward traffic to individual mobiles and predicts the return bandwidth requirements which are likely to result from the forward traffic.

Abstract: In a frame sync method, a receiver searches for the presence of an N-symbol long unique word pattern. For each possible frame sync detected, the receiver proceeds to demodulation and FEC processing. After each iteration of the FEC decoder, the detected unique word pattern is compared to the expected one and the frame sync is detected if the number of unique word errors has decreased.

Abstract: In a frame sync method, a receiver searches for the presence of an N-symbol long unique word pattern. For each possible frame sync detected, the receiver proceeds to demodulation and FEC processing. After each iteration of the FEC decoder, the detected unique word pattern is compared to the expected one and the frame sync is detected if the number of unique word errors has decreased.

Abstract: In a wireless communications system, transceivers transmit short bursts to a base station, which determines timing corrections from the time of receipt of the burst and transmits the timing corrections to the respective transceivers. In one aspect, the base station indicates to the transceivers a plurality of time slots, each transceiver selects one of the time slots at random, formats a burst including an indicator of the selected time slot and transmits the burst in that slot. In another aspect, the base station transmits to each transceiver a timing uncertainty value, which determines how the timing correction will be modified by the tranceiver as the interval since last receiving a timing correction increases. Data bursts are transmitted in a format comprising a first unique word, a content field and a second unique word, in that order. The bursts are transmitted in a TDMA channel format which can accommodate both short and long bursts in a block format of constant periodicity.

Abstract: A method for authenticating terminals in a wireless communication service involves receiving registration requests from terminals requiring access, transmitting to each of the terminals a signalling channel assignment signal allocating a duplex signalling channel uniquely to each terminal, transmitting in the signalling channel an authentication request signal, receiving an authentication response signal in the channel, the contents of which depend on the context of the authentication request signal, and deciding whether to allow access to the system according to the contents of the authentication response signal.

Abstract: A wireless communication system uses an adaptive air interface in which burst parameters are variable on a burst-by-burst basis, based on the reception quality of previous bursts and/or properties of the receiver or receivers of the burst. The parameter values are selected as sets which represent only some of the possible combinations of parameter values, to avoid redundancy in performance characteristics. Coding rates are selected to give a substantially constant increment in gain. Each burst may contain multiple FEC blocks with different coding rates. A unique word indicates the FEC coding rate of the first block and the first block identifies the coding rate of each of the subsequent blocks.

Abstract: In a bandwidth allocation protocol for a mobile communications network, mobile terminals report their bandwidth requirements to the network, while the network controls the amount of bandwidth that is used by the mobiles in reporting their bandwidth requirements. The mobiles indicate the total quantity of data awaiting transmission, the maximum delay time of the most urgent portion of the data and the maximum delay time of the least urgent portion. If a collision occurs between transmission by two mobiles, the mobiles wait for an interval controlled by the network before attempting another contention-based access transmission. The network periodically varies the contention-based access capacity available according to the observed usage level and/or collision rate in the previously allocated contention-based access capacity. The network analyses the forward traffic to individual mobiles and predicts the return bandwidth requirements which are likely to result from the forward traffic.

Abstract: In a wireless communications system, transceivers transmit short bursts to a base station, which determines timing corrections from the time of receipt of the burst and transmits the timing corrections to the respective transceivers. In one aspect, the base station indicates to the transceivers a plurality of time slots, each transceiver selects one of the time slots at random, formats a burst including an Indicator of the selected time slot and transmits the burst in that slot. In another aspect, the base station transmits to each transceiver a timing uncertainty value, which determines how the timing correction will be modified by the tranceiver as the interval since last receiving a timing correction increases. Data bursts are transmitted in a format comprising a first unique word, a content field and a second unique word, in that order. The bursts are transmitted in a TDMA channel format which can accommodate both short and long bursts in a block format of constant periodicity.

Abstract: In a frame sync method, a receiver searches for the presence of an N-symbol long unique word pattern. For each possible frame sync detected, the receiver proceeds to demodulation and FEC processing. After each iteration of the FEC decoder, the detected unique word pattern is compared to the expected one and the frame sync is detected if the number of unique word errors has decreased.

Abstract: A method of transmission in a TDMA channel comprises transmitting first communications traffic using a first TDMA protocol in first selected periods of the TDMA channel and transmitting second communications traffic using a second TDMA protocol incompatible with the first TDMA protocol in second selected periods of the TDMA channel other than said first periods.

Abstract: A mobile terminal (6) communicates via a satellite (8), which projects a number of overlapping spot beams (10), with a fixed earth station (2). To determine which spot beam (10) is to be used for communication, the mobile terminal signals in a common signalling channel which is simultaneously received by all, or a subgroup of, the spot beams (10). The satellite (8) retransmits to the fixed earth station (2) in separate channels the signal as received by each of the spot beams (10) which are able to receive the common signalling channel. The relative strengths of the signal as received in the different spot beams (10) are compared at the fixed earth station and a communications channel is assigned to the mobile terminal in one of the spot beams (10), selected according to the comparison of signal strengths.