Method and apparatus for the transmission of energy-scaled variable rate data

• US 5,841,806 A
• Filed: 05/16/1995
• Issued: 11/24/1998
• 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): Chin, Wellington
• Assistant Examiner(s): Luther, William
• Application Number:
  US08/441,894
• Time in Patent Office: 1,288 Days
• Field of Search: 375/200, 375/206, 375/205, 375/222, 375/225, 375/298, 375/299, 375/308, 375/295, 375/267, 375/278, 375/279, 375/284, 375/283, 375/285, 375/297, 375/313, 370/18, 370/21, 370/84, 370/22, 370/19, 370/208, 370/209, 370/204, 370/342, 379/59, 455/33.1, 455/54.1, 380/34, 341/61
• US Class Current: 375/146
• 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

An apparatus for communicating variable rate data over a communication channel. A modulator that receive frames of user data each comprised of data symbols. The modulator repeats the data symbols within each frame to maintain a constant data rate. A transmitter receiver the modulator data and scales the modulated symbol data based upon the amount of symbol repetition in the frame.

Claims

1. An apparatus for communicating variable rate data over a communication channel, comprising:

modulation means for receiving frames of user data each comprised of data symbols each having a symbol energy, and for generating constant rate frames by repeating said data symbols within each of said frames of user data having a number of data symbols less than a predetermined maximum number in order to maintain a constant data rate;

transmit means connected to said modulation means for scaling symbol energy of said data symbols of said constant rate frames according to predetermined scaling factors in order to produce energy scaled data symbols, said transmit means reducing said symbol energy of said data symbols within ones of said constant rate frames in which said data symbols are repeated, and transmitting said energy scaled data symbols over said communication channel.

2. The apparatus of claim 1 wherein said transmit means comprises:

a filter for receiving and filtering said data symbols of said constant rate frames in accordance with said predetermined scaling factors to provide said energy scaled data symbols; and

a transmitter coupled to said filter for transmitting said energy scaled data symbols.

3. The apparatus of claim 2 wherein said filter is a finite impulse response (FIR) filter having filter coefficients, said filter responsive to a scaling signal indicative of said scaling factor for selecting values of said filter coefficients for energy scaling said data symbols of said constant rate frames.

4. The apparatus of claim 2 wherein said filter is a finite impulse response (FIR) filter that is responsive to a data rate signal indicative of a data rate of said frames of user data wherein said data rate signal is used in selection of filter coefficients of said FIR filter, said FIR filter energy scaling said data symbols of said constant rate frames in accordance with said filter coefficients.

5. The apparatus of claim 1 further comprising encoder means for receiving user input frames of user data each comprised of data bits, encoding said data bits of said user input frames according to a predetermined encoding format to produce said frames of user data each comprised of said data symbols.

6. The apparatus of claim 1 wherein said modulation means comprises:

an interleaver having an input for receiving said frames of user data and an output; and

a spread spectrum modulator having an input coupled to said interleaver and an output coupled to said transmit means.

7. The apparatus of claim 6 further comprising an encoder having an input for receiving frames of user data each comprised of data bits and having an encoder output coupled to said interleaver input, said encoder encoding said frames of data bits according to a predetermined encoding format to produce frames of data symbols.

8. In a spread spectrum communication system, an apparatus for transmitting variable rate data, comprising:

an interleaver having an input and an output, said interleaver converting variable rate symbol data to constant rate symbol data and interleaving said constant rate symbol data;

a spread spectrum modulator having an input and an output, said modulator input coupled to said interleaver output and said modulator for direct sequence spread spectrum modulating said interleaved constant rate symbol data;

finite impulse response filter having an input and an output, said filter input coupled to said modulator, said filter energy scaling said modulated symbols by predetermined energy scaling factors to provide an energy scaled signal; and

a transmitter having an input coupled to said filter output for transmitting said energy scaled signal.

9. The apparatus of claim 8 wherein said filter is responsive to a data rate signal for determining filter scaling coefficients.

10. The apparatus of claim 8 further comprising an encoder having an input for receiving for variable rate bit data, said encoder error correction encoding said variable rate bit data and providing at an output coupled to said interleaver said variable rate symbol data.

11. A method for communicating variable rate data over a communication channel, comprising the steps of:

receiving frames of user data each comprised of data symbols each having a predetermined symbol energy;

generating constant rate frames by repeating said data symbols within each of said frames of user data having a number of data symbols less than a predetermined maximum number data symbols to maintain a constant data rate;

scaling symbol energy of said data symbols of said constant rate frames according to predetermined scaling factors in order to produce energy scaled data symbols, and reducing said symbol energy of said data symbols within ones of said constant rate frames in which said data symbols are repeated; and

transmitting said energy scaled data symbols over said communication channel.

12. The method of claim 11 further comprising the step of encoding frames of data bits according to a predetermined encoding format to produce said frames of data symbols.

13. The method of claim 11 further comprising the step of interleaving said frames of symbol data bits according to a predetermined interleaving format.

14. The method of claim 11 further comprising the step of spread spectrum modulating said data symbols and said repeated data symbols.

15. The method of claim 13 further comprising the step of encoding frames of data bits according to a predetermined encoding format to produce said frames of data symbols.

16. The method of claim 14 further comprising the step of spread spectrum modulating said data symbols and said repeated data symbols.