| 摘要 |
A wireless communications network, including a base station ( 10 ) and wireless units (UE), is disclosed. The wireless units (UE) request a connection with the base station ( 10 ) by the transmission of a preamble within time slots designated by the base station ( 10 ). The disclosed preambles are Walsh Hadamard code symbols, repeated a number of times so as to have the same length as a cell-specific scrambling code. The wireless unit (UE) requesting a connection pseudo-randomly selects a time slot from those available, and one of the Walsh Hadamard code symbols, replicates the code symbol into a spread interleaved bitstream, scrambles this bitstream and transmits it to the base station ( 10 ). Upon receipt, the base station ( 10 ) applies the incoming bitstream to a matched filter ( 98 ) to descramble the signal, following which the symbol is de-interleaved by way of a sequence of delay lines ( 100 ). Despreaders ( 102 ) generate each bit of the symbol from corresponding taps of the delay lines ( 100 ), and the symbol is applied to a correlator ( 104, 126, 136 ) to determine the transmitted preamble.
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