Abstract: Method of synchronizing base stations in a mobile radio telecommunication system, characterized in that a first base station transmits a synchronisation sequence having a first sequence followed by a second sequence, the said first and second sequences being obtained from polyphase complementary sequences and in that at least one second base station effects the correlation of the said synchronization sequence with a replica of the first sequence and a replica of the second sequence, the correlation results then being added in order to provide synchronization information.

Abstract: A preamble for a reverse access channel (RACH) of a CDMA (code division multiple access) communications system comprises a pair of constituent Golay sequences A and B concatenated with at least one pair, and preferably a plurality of different pairs, of transformed sequences which are also constituent Golay sequences, each pair of transformed sequences comprising a permutation of elements of the pair of sequences A and B. The permutations can include a reversed order of elements in the sequences, a reversed order of some or all of a set of address bits identifying locations of elements in the sequences, a concatenation of subsets of elements in odd and even locations of the sequences A and B, and combinations of these permutations. A method for providing the preamble, and related apparatus using a bidirectional counter and an address permutation unit, are described.

Abstract: An approach for providing message synchronization in a communication system is disclosed. Using a selected channel coding method (e.g., Golay coding), an encoder encodes a message for transmission over a communication channel. An interleaver applies a predetermined interleaving pattern to the encoded message. A mask pattern with a prescribed sequence of bits is applied to the interleaved message; the prescribed sequence is ordered to eliminate an all zeros bit pattern and an all ones bit pattern. A multiplexer multiplexes the masked message with data traffic over the communication channel. The masked message is segmented into multiple blocks of a fixed length. At the receiver side, the mask pattern is applied to the demultiplexed message. The message is de-interleaved and decoded to restore the original message.

Abstract: An apparatus and method for generating a cyclic redundancy code with multiple cyclic redundancy code circuits are disclosed. High throughput data protocols can work more robustly if accompanied by high throughput error checking to verify the integrity of the communicated data. One approach of improving the performance of cyclic redundancy code generation hardware that can save money and development time is to combine multiple cyclic redundancy code circuits to perform the error checking. Data received is processed across the multiple cyclic redundancy code circuits. Future cyclic redundancy code circuits can also be combined according to this approach.

Abstract: A method and apparatus for telemetering data on a channel having a maximum data rate by utilizing a power efficient communication protocol is provided. The data to be telemetered comprises a number of source symbols where each source symbol is characterized by a probability of occurrence. A sequence of signals forming codewords having an energy and a length is produced. The length for the codewords is based at least on the number of symbols to be coded. Each codeword signifies a specified source symbol on the basis of a mapping between source symbols and codewords. The mapping is such that each source symbol of lower probability of occurrence is associated with a codeword of at least equal energy.

Abstract: A method of turbo decoding using soft input-soft output information. A vector of data is sampled from a channel of data. The vector of data is then processed to output a final code word of bits. A final reliability vector of reliability values associated with the final code word is generated, such that each bit of the final code word of bits has a corresponding reliability value in the final reliability vector. Corresponding reliability values for one or more bit positions of the final code word are determined by a difference of distance metrics, and corresponding reliability values for one or more bit positions of the final code word are determined utilizing a numerical approximation.

Abstract: A method 400, phone 203, radio transmitter 205, and communication system 200 including a nonsystematically shortened code encoder 202 having an input 204 adapted to receive input digital signals having a number of bits, the nonsystematically shortened code encoder 202 is adapted to produce encoded shortened code digital signals in accordance with the input digital signals. The communication system further including a nonsystematically shortened code decoder 208 adapted to receive the encoded shortened code digital signals, wherein the nonsystematically shortened code decoder 208 is adapted to produce an estimate of the input digital signals and an error detection flag.

Abstract: The present invention provides a method (400), error control system (200), phone (209) and error control apparatus (208) including a hexacode-based Golay decoder (210) adapted to receive values defining Golay encoded data signals and to generate a estimate of original input data signals (216) and a plurality of metrics associated with Golay encoded data signals, and an error detection circuit (212) coupled to the hexacode-based Golay decoder (210) for comparing the plurality of metrics and providing an error detection flag (214).

Abstract: The present invention provides a method (600), phone (209), and communication system (202) including a systematic encoder (204) adapted to receive input data signals having a first plurality of data bits and generate encoded data signals having the first plurality of data bits and a first plurality of parity bits, a receiver (206) adapted to receive the encoded data signals and to generate values defining the encoded data signals, a decoder (208) coupled to the receiver (206) and adapted to generate a second plurality of data bits in response to the values defining the encoded data signals, and a post-decoder circuit (210) coupled to the decoder (208) adapted to receive the second plurality of data bits and for transforming the second plurality of data bits into an estimate of the first plurality of data bits.

Abstract: An error control decoder receives a received vector to be decoded. The decoder then calculates, as an error estimate, the Euclidean distance between a codeword choice and the received vector. The output error estimate is appropriately scaled and quantized in accordance with the particular code being processed by the decoder. The efficient Conway-Sloane algorithm is extended for use in connection with the decoding of shortened Golay codes. A modification is made to the generator matrix for the Golay code to produce a modified generator matrix that is unique for each shortened code. The modified generator matrix is then implemented in the Conway-Sloane algorithm to identify the best codeword for conversion to its corresponding information bits for output.