Fast forward link power control in a code division multiple access system

• US 5,383,219 A
• Filed: 11/22/1993
• Issued: 01/17/1995
• Est. Priority Date: 11/22/1993
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Wheatley, Charles E. III, Padovani, Roberto, Zehavi, Ephraim
• Primary Examiner(s): Swann, Tod R.
• Application Number:
  US08/156,125
• Time in Patent Office: 421 Days
• Field of Search: 380/34, 375/1, 371/43
• US Class Current: 370/342
• CPC Class Codes: H03M 13/23 using convolutional codes, e.g. unit memory codes
• CPC Class Codes: H04L 1/0015 characterised by the adaptation strategy
• CPC Class Codes: H04L 1/0019 in which mode-switching is based on a statistical approach
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/0027 Scheduling of signalling, e.g. occurrence thereof
• CPC Class Codes: H04L 1/0041 Arrangements at the transmitter end
• 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 1/0054 Maximum-likelihood or sequential decoding, e.g. Viterbi, Fano, ZJ algorithms
• CPC Class Codes: H04L 1/0059 Convolutional codes
• CPC Class Codes: H04L 1/0068 by puncturing
• CPC Class Codes: H04L 1/0069 Puncturing patterns
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04W 52/20 using error rate
• CPC Class Codes: H04W 52/267 taking into account the information rate

Abstract

The power control process of the present invention enables a mobile radiotelephone to continuously update the base station on the power output required. The base station sends a frame to the mobile at a particular rate. If the mobile received and decoded the frame correctly, it sets a power control bit in the next frame to be transmitted to the base station. Based on the error rate of the received power control bits, the base station determines whether to increase or decrease the transmit power.

Claims

1. A method for providing a variable rate data communication link, the method comprising the steps of:

convolutionally encoding an input data signal to produce a first plurality of convolutionally encoded signals, each convolutionally encoded signal comprising a plurality of data symbols;

repeating each data symbol a predetermined number of times to produce a second plurality of convolutionally encoded signals comprising a plurality of repeated data symbols;

multiplexing the second plurality of convolutionally encoded signals to produce a data sequence;

puncturing the data sequence such that data symbols in predetermined locations of the data sequence are deleted to produce a punctured data sequence; and

interleaving the data sequence to produce an interleaved data sequence.

2. The method of claim 1 wherein the data sequence is punctured every 6n+3 and 6n+5 data symbols.

3. The method of claim 1 and further including the step of assigning a null metric to each deleted symbol.

4. A method for enabling an input data signal to be input to a convolutional encoder at a variable rate while maintaining a constant data rate output from the convolutional encoder, the convolutional encoder operating in a radiotelephone having the capability of communicating with a base station over forward and reverse communications links in a code division multiple access communication system, the method comprising the steps of:

convolutionally encoding the input dam signal, thus producing two encoded output signals comprising a plurality of data symbols;

repeating each data symbol in each encoded output signal;

multiplexing the repeated data symbols of each encoded output signal to form a first data sequence;

deleting every 6n+3 and 6n+5 data symbols of the data sequence, where n is an integer in the range of 0 to ∞

producing a punctured data sequence;

interleaving the punctured data sequence to produce an interleaved data sequence;

modulating the interleaved data sequence;

transmitting the interleaved data sequence over the forward communications link;

the base station receiving the interleaved data sequence;

demodulating the received data sequence to produce a demodulated data sequence;

deinterleaving the demodulated data sequence to produce a deinterleaved data sequence;

inserting a null metric every 6n+3 and 6n+5 data symbols in the deinterleaved data sequence to produce a second data sequence;

decoding the second data sequence; and

digital to analog converting the decoded, second data sequence.

5. The method of claim 4 wherein the input data signal has a data rate of 14.4 kbps and the output signal has a data rate of 19.2 kbps.