Method and apparatus for multiplexing control information into a user signal stream of a CDMA cellular system

• US 5,440,542 A
• Filed: 10/14/1993
• Issued: 08/08/1995
• Est. Priority Date: 10/14/1993
• Status: Expired due to Fees

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Procter, Lee M., Jayapalan, Jay P.
• Primary Examiner(s): Kizou, Hassan
• Application Number:
  US08/114,943
• Time in Patent Office: 663 Days
• Field of Search: 370/18, 370/95.1, 370/95.3, 370/110.1, 370/111, 370/118, 370/55, 370/112, 379/59, 379/60, 379/63, 455/33.1, 455/33.2, 455/54.1, 455/68, 375/1
• US Class Current: 370/335
• 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: H04W 88/181 Transcoding devices; Rate adaptation devices

Abstract

A method and apparatus is offered of multiplexing control information into a user signal stream in a cellular communication system using code division multiple access. The method includes the steps of determining a temporal measure (101) of control information to be substituted for a corresponding measure of user information, substituting (102) the control information into the signal stream while buffering a corresponding temporal measure of user information, and resuming transmission (103) of user information beginning with the buffered user information.

Claims

1. In a base station controller of a cellular communication system using code division multiple access encoding, a method of multiplexing control information for a communication unit into a user signal stream, the method comprising the steps of:

receiving at a transcoder of the base station from an interworking function of the cellular system, user information to be encoded and communicated to the communication unit in the user signal stream;

receiving at the transcoder control information to be inserted in the user signal stream;

determining a temporal measure of the received control information;

inserting the control information into the user signal stream while buffering a corresponding temporal measure of user information;

communicating the temporal measure to the interworking function by marking a corresponding temporal measure of information communicated from the transcoder to the interworking function on a reverse channel;

generating, within the interworking function, a set of null characters temporally equal to the temporal measure; and

substituting the buffered user information for the null characters.

2. The method of claim 1 wherein the step of communicating the temporal measure of user information to the interworking function by marking a corresponding temporal measure of information on a reverse channel comprises setting a status bit in a plurality of communication frames being communicated on the reverse channel temporally equal to the corresponding temporal measure.

3. The method of claim 2 wherein the step of generating, within the interworking function, a set of null characters temporally equal to the buffered user information comprises generating null frames in one-for-one correspondence to the plurality of communication frames having a set status bit.

4. An apparatus for multiplexing a control signal intended for a communication unit of a cellular communication system into a user signal stream at a base station controller, the apparatus comprising:

a transcoder operably interconnected with the base station controller and an interworking function;

a register within the transcoder for receiving the control signal from the base station controller;

a first processor within the transcoder for determining a temporal length of the control signal;

a second processor for inserting the control signal into the user signal stream while buffering a corresponding temporal length of user information received from the interworking function;

a signal path associated with information being communicated on a reverse channel from the transcoder to the interworking function for communicating the temporal length of the buffered user information to the interworking function;

a third processor within the interworking function for generating null characters within the user signal stream for a time period substantially equal to the temporal length of the buffered user information; and

a fourth processor within the transcoder for substituting the buffered user information for the null characters.

5. The apparatus of claim 4 wherein the signal path comprises status bits associated with the information being communicated on the reverse channel for indicating the amount of null characters to be generated.