ASYMMETRICAL FORWARD/REVERSE TRANSMISSION BANDWITH
A wireless communications system employs code-division multiple access information transmission techniques where the uplink and downlink transmission bandwidths are unequal. The higher bandwidth is an integer multiple of the lower bandwidth. The present system requires a base station and a subscriber unit to have two pseudo-random code generators which can be clocked separately. Alignment of the uplink and downlink pseudo-random spreading codes is achieved by truncating the code sequence for the lower speed link at the conclusion of a complete code sequence for the higher speed link.
1 . A method for code division multiple access (CDMA) in a wireless network, comprising:
dispreading, by a processor, a code modulated signal with at least one output code sequence, the code modulated signal received via a wireless medium;
demodulating, by a radio front end, the code modulated signal with at least one carrier;
aligning, by a sequence generator circuit coupled to the processor and the radio front end and the processor, a first pseudo-random sequence and a portion of a second pseudo-random sequence at a conclusion of the first pseudo-random sequence, wherein the second pseudo-random sequence having a length greater than a length of the first pseudo-random sequence; and
combining, by the sequence generator circuit, the aligned first pseudo-random sequence and the second aligned pseudo-random sequence to generate the at least one output code sequence, wherein a length of the output code sequence is equivalent to a length of the aligned first pseudo-random sequence.