Efficient signaling for closed-loop transmit diversity

摘要

Techniques for encoding a phase adjustment for a feedback signal in a closed-loop transmit diversity system. In an aspect, codewords for the phase adjustments are chosen according to a variable-length prefix code. The prefix code aspect allows the codewords to be transmitted in sequence on the feedback channel without being separated by “commas” or demarcation symbols. The variable-length aspect provides a variety of coarse and fine phase adjustment quantization step sizes to accommodate multiple different channel scenarios. In an aspect, the length of the codewords may be further optimized according to the Huffman encoding algorithm.

主权项

1. An apparatus for transmitting information on a feedback channel, the apparatus comprising:
a receiver configured to receive a signal on a primary channel; an update calculation module configured to determine an adjustment to be applied on the primary channel based on the received signal; an encode module configured to encode the adjustment to be applied using a variable-length prefix code, wherein a length and a bit value of the variable-length prefix code vary for different adjustments each of which includes a different phase adjustment, and wherein the length and the bit value of the variable-length prefix code are independent of a resolution of a phase adjustment associated with the variable-length prefix code; wherein the variable-length prefix code has a property that there is no valid codeword that is a prefix of any other valid variable-length prefix code; and a transmitter configured to transmit the encoded adjustment on the feedback channel.