System and method for generating signal waveforms in a CDMA cellular telephone system

• US 5,715,236 A
• Filed: 11/24/1993
• Issued: 02/03/1998
• Est. Priority Date: 06/25/1990
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Wheatley, Charles E. III, Gilhousen, Klein S., Padovani, Roberto, Jacobs, Irwin M., Viterbi, Andrew J., Weaver, Lindsay A. Jr.
• Primary Examiner(s): Gregory, Bernarr E.
• Application Number:
  US08/156,757
• Time in Patent Office: 1,532 Days
• Field of Search: 375/1, 375/37, 375/59, 375/68, 375/200-204, 375/206-210, 375/254, 375/295, 375/309, 380/28, 380/33, 380/49, 380/34, 370/18, 370/19, 370/21, 370/22, 370/203, 370/208, 370/209, 370/210, 379/58-60, 455/33.15, 455/3.1, 455/54.1, 455/54.2
• US Class Current: 370/209
• CPC Class Codes: H04B 1/3888 Arrangements for carrying or protecting transceivers
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 1/70757 with increased resolution, i.e. higher than half a chip H04B1/70758 takes precedence
• CPC Class Codes: H04B 1/709 Correlator structure
• CPC Class Codes: H04B 1/7115 Constructive combining of multi-path signals, i.e. RAKE receivers
• CPC Class Codes: H04B 2201/70701 featuring pilot assisted reception
• CPC Class Codes: H04B 2201/70703 using multiple or variable rates
• CPC Class Codes: H04B 7/2618 using hybrid code-time division multiple access [CDMA-TDMA]
• CPC Class Codes: H04B 7/2628 using code-division multiple access [CDMA] or spread spectrum multiple access [SSMA] H04B7/2618 takes precedence
• CPC Class Codes: H04B 7/2637 for logical channel control
• CPC Class Codes: H04J 13/0022 PN, e.g. Kronecker
• CPC Class Codes: H04J 13/0048 Walsh
• CPC Class Codes: H04J 13/10 Code generation
• CPC Class Codes: H04J 13/107 by concatenation
• CPC Class Codes: H04J 13/18 Allocation of orthogonal codes
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04L 1/0006 by adapting the transmission format
• CPC Class Codes: H04L 1/0046 Code rate detection or code type detection H04L1/0038 takes precedence; detection of the data rate H04L25/0262; for packet format H04L1/0091
• CPC Class Codes: H04L 1/0065 Serial concatenated codes
• CPC Class Codes: H04L 1/0068 by puncturing
• CPC Class Codes: H04L 1/0071 : Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/06 : using space diversity
• CPC Class Codes: H04L 1/08 : by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04L 23/02 : adapted for orthogonal signalling
• CPC Class Codes: H04L 5/02 : Channels characterised by the type of signal
• CPC Class Codes: H04L 5/12 : the signals being represented by different phase modulations of a single carrier
• CPC Class Codes: H04W 52/26 : using transmission rate or quality of service QoS [Quality of Service]
• CPC Class Codes: Y02D 30/50 : in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A system and method for communicating information signals using spread spectrum communication techniques. PN sequences are constructed that provide orthogonality between the users so that mutual interference will be reduced, allowing higher capacity and better link performance. With orthogonal PN codes, the cross-correlation is zero over a predetermined time interval, resulting in no interference between the orthogonal codes, provided only that the code time frames are time aligned with each other. In an exemplary embodiment, signals are communicated between a cell-site and mobile units using direct sequence spread spectrum communication signals. In the cell-to-mobile link, pilot, sync, paging and voice channels are defined. Information communicated on the cell-to-mobile link channels are, in general, encoded, interleaved, bi-phase shift key (BPSK) modulated with orthogonal covering of each BPSK symbol along with quadrature phase shift key (QPSK) spreading of the covered symbols. In the mobile-to-cell link, access and voice channels are defined. Information communicated on the mobile-to-cell link channels are, in general, encoded, interleaved, orthogonal signalling along with QPSK spreading.

Claims

1. A modulation system for use in spread spectrum communications, comprising:

means for generating a first orthogonal sequence signal corresponding to a selected one of a plurality of orthogonal binary sequences;

means for generating a pseudo-noise (PN) signal corresponding to a predetermined PN binary sequence;

means for combining said first orthogonal sequence signal and said PN signal and for providing a resultant first modulation signal.

2. A high-capacity-spread-spectrum transmitter, handling at least spread-spectrum signals for use with a communications channel, comprising:

a plurality of data signals;

generic means for generating a generic-chip-code signal;

a plurality of message means for generating a plurality of message-chip-code signal wherein each message-chip-code signal is orthogonal to the other message-chip-code signals of plurality of message-chip-code signals, and is synchronized to the generic-chip-code signal;

a plurality of spreading means coupled to said demultiplexer means and said plurality of message means, respectively, for spread-spectrum processing the plurality of demultiplexed-data signals with the plurality of message-chip-code signals to generate a plurality of spread-spectrum processed signals, respectively;

summer means for combining the generic-chip-code signal with the plurality of spread-spectrum processed signals;

transmitter means for transmitting the combined generic-chip-code signal and plurality of spread-spectrum-processed signals, on a carrier signal over said communications channel as a spread-spectrum communications signal.

3. The high-capacity-spread-spectrum transmitter as set forth in claim 2, wherein:

said generic means includes a transmitter-generic-chip-code generator for generating the generic-chip-code signal;

each of said message means includes a transmitter-message-code-chip generator synchronized to the generic-chip-code signal for generating the message-chip-code signal;

each of said spreading means includes an EXCLUSIVE-OR gate for spread-spectrum processing the plurality of demultiplexed-data signals with the message-chip-code signal; and

said summer means includes a combiner for combining the plurality of generic-chip-code signals and the plurality of spread-spectrum-processed signals.