Apparatus and method for determining transmitted modulation symbols

• US 5,784,293 A
• Filed: 11/03/1994
• Issued: 07/21/1998
• Est. Priority Date: 11/03/1994
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Lipa, Robert A.
• Primary Examiner(s): Ramirez, Ellis B.
• Assistant Examiner(s): ASSOUAD, PATRICK J
• Application Number:
  US08/334,162
• Time in Patent Office: 1,356 Days
• Field of Search: 364/514 R, 364/727, 375/200, 375/310, 375/322, 371/43, 332/103, 329/304, 370/22, 370/19, 370/21
• US Class Current: 708/410
• CPC Class Codes: H04B 1/707 using direct sequence modulation

Abstract

A receiver (100) employs an apparatus (109) and method (500) for determining transmitted modulation symbols contained in a received communication signal (127). Each of a plurality of memory locations (201-208) is loaded (503) with a binary representation (120) of a corresponding portion of the received communication signal (127). At least three of the binary representations (120) are transformed (505) in parallel into signed magnitudes (121) that correspond to the received modulation symbols. The magnitudes (121) are then used (507, 509) in the search and demodulation process (113) to recover the originally transmitted modulation symbols.

Claims

1. In a receiver of a communication system a method of transforming signals comprising the steps of:

a) during a first portion of a transform process, performing a first vector mapping, the first vector mapping comprising forming a first group of selectable connections between a memory and a digital computation unit; and

b) during a second portion of the transform process performing a second vector mapping, the second vector mapping comprising forming a second group of selectable connections between the memory and the digital computation unit, the second vector mapping differing from the first vector mapping.

2. The method of claim 1, wherein the transform process comprises a Fast Hadamard Transform.

3. The method of claim 1, further comprising the steps of:

loading each of a plurality of memory locations with a binary representation of a corresponding portion of a received communication signal to produce a plurality of binary representations; and

transforming at least three binary representations of the plurality of binary representations in parallel to produce a plurality of transformed representations that correspond to at least one of the transmitted symbols.

4. The method of claim 3, further comprising the step of:

determining, based on the plurality of transformed representations, at least one of the transmitted symbols.

5. The method of claim 4, wherein the determining step comprises the steps of:

using the plurality of transformed representations to produce a plurality of symbol energies;

selecting a set of symbol energies from the plurality of symbol energies having higher energy values than energy values of symbol energies of the plurality of symbol energies not in the set; and

determining a transmitted symbol of the transmitted symbols associated with each symbol energy in the set.

6. The method of claim 5, wherein the step of determining a transmitted symbol further comprises the steps of:

determining an in-phase component of the transmitted symbol; and

determining a quadrature component of the transmitted symbol.

7. The method of claim 5, wherein each of the transmitted symbols comprises an in-phase component and a quadrature component.

8. The method of claim 3, wherein each of the plurality of transformed representations comprises a plurality of bits that represent a magnitude of at most one of the transmitted symbols.

9. The method of claim 3, wherein said transforming step comprises the step of transforming four of the plurality of binary representations in parallel to produce the plurality of transformed representations.

10. The method of claim 3, wherein each of the transmitted symbols comprises a Walsh symbol and wherein each of the plurality of binary representations comprises a Walsh chip.

11. In a receiver of a communication system a method for determining transmitted symbols contained in a received communication signal, the method comprising the steps of:

a) parallel loading a plurality of memory locations at least two at a time until each of the plurality of memory locations contains a binary representation of a corresponding portion of the received communication signal to produce a plurality of binary representations;

b) transforming four binary representations of the plurality of binary representations in parallel to produce a plurality of transformed representations that correspond to at least one of the transmitted symbols, and

c) reconfiguring a plurality of multiplexors to reconfigure connections between the plurality of memory locations and a plurality of computation units before producing the plurality of transformed representations.