Apparatus and methods for sample selection and reuse of rake fingers in spread spectrum systems

An apparatus for processing data in a spread spectrum system, comprising:

• a decimation circuit having an associated decimation factor;
• a memory, which is a circular buffer including multiple registers, coupled to said decimation circuit;
• an interpolation circuit coupled to said memory, said interpolation circuit having an associated interpolation factor;
• and
• a plurality of despreaders, wherein each of said plurality of despreaders includes:
• a selector circuit;
• and
• a rake finger;
• wherein said decimation circuit decimates a data rate of received data by said decimation factor to a decimated rate and stores said received data into said memory at said decimated rate;
• wherein said interpolation circuit interpolates said decimated rate by said interpolation factor to an interpolated rate and retrieves said received data from said memory at said interpolated rate;
• and
• wherein said selector circuit includes a first set of multiplexers for selecting in-phase data, a second set of multiplexers for selecting quadrature data, and multiple sample select lines coupled to each rake finger.

An apparatus for processing data, comprising:

• a plurality of rake fingers;
• a memory for storing data at the input to said plurality of rake fingers;
• and
• a selector circuit positioned between said memory and each of said plurality of rake fingers;
• wherein said plurality of rake fingers can access said memory substantially simultaneously via a respective selector circuit, and
• wherein said selector circuit includes a first plurality of multiplexers for selecting in-phase data from said memory, a second plurality of multiplexers for selecting quadrature data from said memory, and a set of select lines for controlling data being selected by said first plurality of multiplexers and said second plurality of multiplexers.

An apparatus for processing data, comprising:

• a plurality of rake fingers;
• a memory, which is a single-port RAM, for storing data at the input to said plurality of rake fingers;
• and
• a selector circuit positioned between said memory and each of said plurality of rake fingers;
• wherein said plurality of rake fingers can access said memory substantially simultaneously via a respective selector circuit;
• and
• wherein said memory is divided into memory blocks such that, during each processing cycle, a first subset of said memory blocks is in a Read mode and a second subset of said memory blocks is in a Write mode.

An apparatus for processing data in spread spectrum systems, comprising:

• a memory coupled to a set of despreaders via a bus;
• each of said set of despreaders including:
• a block multiplexer coupled to said bus;
• a set of sample multiplexers coupled to said block multiplexer;
• a cache coupled to said sample multiplexers;
• and
• a rake finger coupled to said cache;
• and
• wherein said set of despreaders can access samples stored in said memory substantially simultaneously via said bus.