Method and apparatus for increasing the number of orthogonal signals using block spreading

Abstract

Embodiments of the invention apply block spreading to transmitted signals to increase the number orthogonally multiplexed signals. The principle of the disclosed invention can be applied to reference signals, acknowledgement signals, and channel quality indication signals. In any given time interval, the set of transmitted signals is defined by two sequences: the baseline sequence, and the block spreading sequence. Different transmitters using the same baseline sequence can be identified by using different block spreading sequences.

1 - 24 . (canceled) 
   
   
       25 . A method of separating transmitters, comprising the steps of:
 receiving a signal transmitted by a first transmitter using a first baseline sequence employing a first block-spreading sequence;   receiving a signal transmitted by a second transmitter using the first baseline sequence employing a second block-spreading sequence; and   using the first and second block-spreading sequences to separate the first and second transmitters.   
   
   
       26 . The method of  claim 25 , wherein said first sequence is based on a constant amplitude zero cyclic auto-correlation (CAZAC) sequence. 
   
   
       27 . The method of  claim 26 , wherein said CAZAC sequence is a Zadoff-Chu sequence. 
   
   
       28 . The method of  claim 25 , wherein said signal is one of:
 a reference signal;   an acknowledgement signal; and   a channel quality indication signal.   
   
   
       29 . An apparatus, comprising:
 circuitry for receiving a signal transmitted by a first transmitter using a first baseline sequence employing a first block-spreading sequence;   circuitry for receiving a signal transmitted by a second transmitter using the first baseline sequence employing a second block-spreading sequence; and   circuitry for using the first and second block-spreading sequences to separate the first and second transmitters.   
   
   
       30 . The apparatus of  claim 29 , wherein the first baseline sequence is based on a constant amplitude zero cyclic auto-correlation (CAZAC) sequence. 
   
   
       31 . The apparatus of  claim 30 , wherein said CAZAC sequence is a Zadoff-Chu sequence. 
   
   
       32 . The apparatus of  claim 29 , wherein said signal is one of:
 a reference signal;   an acknowledgement signal; and   a channel quality indication signal.