Method and system for data and voice transmission over shared and dedicated channels

Abstract

In one disclosed embodiment, data information is stored in a buffer in a transmitter. The data information is transmitted on a shared channel and control information for recovering the associated data information is transmitted on a dedicated channel. The shared and dedicated channels can be, for example, different portions of the frequency band. The control information can include a spreading factor used to spread the data at the transmitter. For example, the spreading factor can be the length of the Walsh function orthogonal coding used to spread the data. The control information is received over the dedicated channel before the associated data information is received over the shared channel. The control information is then used to recover the associated data information. For example, knowing the spreading factor from the control information, the correct Walsh function can be selected to de-spread, i.e. to Walsh de-cover, the data information.

What is claimed is: 
     
         1 . A method for receiving first and second signals in a code division multiple access system, comprising:
 receiving, by a subscriber unit, said first signal via a first coded downlink channel;   retrieving, by the subscriber unit, access information for said second signal from said first signal, the access information comprising spreading factor information;   receiving, by the subscriber unit, said second signal via a second coded downlink channel; wherein a start of said second signal on the second coded downlink channel was delayed by a delay sufficient for the spreading factor information to be extracted, by the subscriber unit, from a portion of said first signal prior to reception of a first data frame of said second signal;   extracting, by the subscriber unit, the spreading factor information from the portion of said first signal; and   accessing said second signal using the spreading factor information retrieved from said first signal.   
     
     
         2 . The method as in  claim 1  further comprising despreading said second signal at symbol level after said accessing said second signal using said access information. 
     
     
         3 . The method as in  claim 2  wherein said system comprises a wideband code division multiple access (WCDMA) system, said first coded downlink channel is a dedicated physical channel (DPCH), and said second coded downlink channel is a physical downlink shared channel (PDSCH) in said WCDMA system. 
     
     
         4 . The method of  claim 1 , wherein said receiving said second signal comprises receiving a plurality of frames comprising user data and wherein each of said plurality of frames includes a different spreading factor. 
     
     
         5 . The method as in  claim 1 , wherein:
 said plurality of frames each comprise a plurality of slots; and said delay is equal to three to eighteen slots.   
     
     
         6 . A subscriber unit for receiving first and second signals in a code division multiple access system, comprising:
 a receiver configured to:
 receive said first signal via a first coded downlink channel; 
 retrieve access information for said second signal from said first signal, the access information comprising spreading factor information; 
 receive said second signal via a second coded downlink channel; wherein the start of said second signal on the second coded downlink channel is configured to be delayed by a delay sufficient for the spreading factor information to be extracted, by the subscriber unit, from a portion of said first signal prior to reception of a first data frame of said second signal; 
 extract the spreading factor information from the portion of said first signal; and 
 access said second signal using the spreading factor information retrieved from said first signal. 
   
     
     
         7 . The subscriber unit of  claim 6  wherein the receiver is further configured to despread said second signal at symbol level after said accessing said second signal using said access information. 
     
     
         8 . The subscriber unit of  claim 7  wherein said system comprises a wideband code division multiple access (WCDMA) system, said first coded downlink channel is a dedicated physical channel (DPCH), and said second coded downlink channel is a physical downlink shared channel (PDSCH) in said WCDMA system. 
     
     
         8 . The subscriber unit of  claim 6 , wherein the receiver is further configured to receive a plurality of frames in said signal where the plurality of frames comprise user data and wherein each of said plurality of frames includes a different spreading factor. 
     
     
         9 . The subscriber unit of  claim 6 , wherein:
 said plurality of frames each comprise a plurality of slots; and   said delay is equal to three to eighteen slots.   
     
     
         10 . A receiver for receiving a plurality of frames of data from a transmitter in a communications system, the receiver comprising:
 a finite impulse response (FIR) filter configured to receive an pseudo-noise spread first signal via a first downlink channel and a pseudo-noise spread second signal via a second downlink channel, where there is a delay between the first and a second signal and wherein the first signal comprises access information for accessing relevant frames of data from the plurality of frames of data, the access information comprising spreading factor information, and wherein said delay is sufficient for the spreading factor information to be extracted from a portion of said first signal by the receiver prior to reception of a first data frame of said second signal, the spreading factor information being associated with the first data frame of the second signal, to avoid chip level signal buffering by the receiver;   a de-spreader configured to de-spread the pseudo noise spread first and second signals;   a Walsh de-cover configured to de-spread the de-spread second signal using spreading factor information retrieved from said first signal to output a sequence a symbols; and   a decoder configured to decode the sequence of symbols.   
     
     
         11 . The receiver of  claim 10 , wherein the plurality of frames comprise frames for a plurality of users, and wherein the access information comprises access information for accessing relevant frames of the plurality of frames associated with receiver. 
     
     
         11 . The receiver of  claim 9 , wherein the receiver is operable in a wideband code division multiple access (WCDMA) system, said first downlink channel is a dedicated physical channel (DPCH), and said second coded downlink channel is a physical downlink shared channel (PDSCH). 
     
     
         12 . The receiver of  claim 9 , wherein:
 said plurality of frames each comprise a plurality of slots; and   said delay is equal to three to eighteen slots.