Radio with synchronization apparatus and method therefore

• US 6,366,786 B1
• Filed: 03/08/1999
• Issued: 04/02/2002
• Est. Priority Date: 04/24/1998
• Status: Expired due to Term

• Current Assignee: North Star Innovations Inc. (Wi-LAN Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Norman, Oded, Refaeli, Moshe, Perlman, Boaz, Salant, Yoram, McAlinden, Paul
• Primary Examiner(s): VO, NGUYEN THANH
• Application Number:
  US09/263,545
• Time in Patent Office: 1,121 Days
• Field of Search: 455/502, 455/517, 375/356, 375/354, 370/503
• US Class Current: 455/502
• CPC Class Codes: H04B 7/2681 Synchronisation of a mobile station with one base station
• CPC Class Codes: H04J 3/0652 Synchronisation among time division multiple access [TDMA] nodes, e.g. time triggered protocol [TTP] bus network with centralized control in which slots are of a TDMA packet structure H04L12/4035
• CPC Class Codes: H04J 3/0655 using timestamps
• CPC Class Codes: H04J 3/0694 Synchronisation in a TDMA node, e.g. TTP
• CPC Class Codes: H04W 92/12 between access points and access point controllers

Abstract

A mobile radio (10) with a synchronization apparatus (14) executes a method (60) for time synchronizing the radio (10) and a base station (12). Base station (12) and radio (10) have internal timers (26, 16). A control unit (18) in the radio (10) receives a signal (29) from the base station (12) and determines the difference F between timers (26, 16, 30) in the base (12) and mobile (10). The control unit (18) writes instructions I(i) and their execution times T(i) to a memory (42) within the radio (10). One of these instructions I(N) reloads the radio timing counter (30) with a corrected value C=f(F,B) at a predetermined time T(N)=B which avoids conflicts with other operations of the radio (10).

Claims

1. A radio having time synchronization, the radio comprising:

a receptor for receiving a timing signal from another radio;

a timing unit providing a timing signal within the radio;

a control unit coupled to the timing unit and the receptor, wherein the control unit provides a timing offset value F based on the timing signal from the another radio;

a memory coupled to the control unit for receiving a series of instructions I(i) from the control unit, the instructions I(i) comprising operand instructions O(i) for controlling operations of the radio and time of execution instructions T(i) specifying when each O(i) is to be executed, where i is an index having values 0, . . . , N, . . . , M;

wherein, the control unit determines a timing unit correction value C=f(B,F) where B is a completion time of instruction I(N−

1), F is the timing offset value and C is a value necessary to bring the timing unit into predetermined relationship with a timing unit of the another radio, and wherein the control unit includes in the instructions I(i) an instruction I(N) embodying an operand O(N) for execution at time T(N), the operand O(N) causing the correction value C to be loaded into the timing unit.

2. The radio of claim 1 wherein the index i is determined by timing signals from the timing unit.

3. The radio of claim 1 wherein the correction value C is placed in a register pending execution of some or all of instructions I(i) for i<

N and wherein instruction I(N) causes C to be transferred from the register to the timing unit upon execution of O(N) at time T(N).

4. The radio of claim 1 wherein values of execution times T(i) for i>

N are adjusted to take into account a change in output of the timing unit after correction value C is loaded therein.

5. The radio of claim 1 wherein the control unit determines the execution times T(i) for i>

N prior to loading I(i) into the memory.

6. The radio of claim 1 wherein the control unit adjusts the execution times T(i) for i>

N after loading some or all of I(i<

N) into the memory.

7. The radio of claim 1 wherein the control unit compares the timing signal received form the another radio with a timing signal from the timing unit to determine F.

8. The radio of claims 1 wherein the control unit detects whether the timing signal from the another radio is a time offset signal or a time signal.

9. A method for operating a radio having instruction execution logic and a radio timing unit to synchronize the radio timing unit with another radio timing unit, comprising the steps of:

receiving another radio timing value from the another radio timing unit;

determining from the another radio timing value a timing difference value F;

providing instructions I(i) to be executed by the radio wherein each instruction I(i) comprises an operand O(i) and an execution time T(i) for the operand, where i is an index;

then in either order,

determining a time N for execution of an Nth instruction I(N) comprising an operand O(N) to be executed at time T(N)=B wherein B is greater than the time of completion of instruction I(N−

1), and

determining a timing unit correction value C=f(B,F); and

operating the instruction execution logic to execute instructions I(i) at time T(i) so that at time T(N), operand O(N) of instruction I(N) causes the correction value C to be loaded into the radio timing unit.

10. The method of claim 9 wherein the index i advances with each output count from the radio timing unit.

11. The method of claim 9 wherein the operating step comprises placing the correction value C in a register pending execution of some or all of instructions I(i) for i<

N and wherein instruction I(N) causes C to be transferred from the register to the timing unit upon execution of O(N) at time T(N).

12. The method of claim 9 wherein the index i is derived from an output count of the timing unit and wherein the method further comprises:

providing instructions I(i) for i>

N, and adjusting values of T(i) for i>

N to take into account changes in the output count of the timing unit after loading the correction value C.