HIGH DATA RATE CDMA WIRELESS COMMUNICATION SYSTEM

• US 20020009096A1
• Filed: 07/01/1997
• Published: 01/24/2002
• Est. Priority Date: 05/28/1996
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: ODENWALDER, JOSEPH P.
• Granted Patent: US 6,396,804 B2
• Time in Patent Office: Days
• US Class Current: 370/441
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 2201/70701 featuring pilot assisted reception
• CPC Class Codes: H04B 7/264 for data rate control
• CPC Class Codes: H04J 13/0044 OVSF [orthogonal variable spreading factor]
• CPC Class Codes: H04J 13/0048 Walsh
• CPC Class Codes: H04J 13/0077 Multicode, e.g. multiple codes assigned to one user
• CPC Class Codes: H04J 13/102 Combining codes
• CPC Class Codes: H04J 13/18 Allocation of orthogonal codes
• CPC Class Codes: H04L 1/0059 Convolutional codes
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04W 52/34 TPC management, i.e. sharing limited amount of power among users or channels or data types, e.g. cell loading
• CPC Class Codes: H04W 52/54 Signalisation aspects of the TPC commands, e.g. frame structure
• CPC Class Codes: H04W 52/60 using different transmission rates for TPC commands

Abstract

A novel and improved method and apparatus for high rate CDMA wireless communication is described. In accordance with one embodiment of the invention, a set of individually gain adjusted subscriber channels are formed via the use of a set of orthogonal subchannel codes having a small number of PN spreading chips per orthogonal waveform period. Data to be transmitted via one of the transmit channels is low code rate error correction encoded and sequence repeated before being modulated with one of the subchannel codes, gain adjusted, and summed with data modulated using the other subchannel codes. The resulting summed data is modulated using a user long code and a pseudorandom spreading code (PN code) and upconverted for transmission. The use of the short orthogonal codes provides interference suppression while still allowing extensive error correction coding and repetition for time diversity to overcome the Raleigh fading commonly experienced in terrestrial wireless systems. In the exemplary embodiment of the invention provided, the set of sub-channel codes are comprised of four Walsh codes, each orthogonal to the remaining set and four chips in duration. The use of four sub-channels is preferred as it allows shorter orthogonal codes to be used, however, the use of a greater number of channels and therefore longer codes is consistent with the invention.

In a first exemplary embodiment of the invention, pilot data is transmitted via a first one of the transmit channels and power control data transmitted via a second transmit channel. In the preferred embodiment the pilot data and control data are combined onto one channel. The remaining two transmit channels are used for transmitting non-specified digital data including user data or signaling data, or both.

Claims

1. A method for generating modulated data for transmission from a first subscriber unit in a set of subscriber units wherein said first subscriber unit transmits control data and pilot data to a base station in communication with the set of subscriber units comprising the steps of:

a) combining said control data with said pilot data; and

b) modulating said combined control data and pilot data onto in accordance with a single channel modulation format.