Synchronizing means for a two-way communication system

• US 4,231,114 A
• Filed: 02/27/1978
• Issued: 10/28/1980
• Est. Priority Date: 02/27/1978
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Dolikian, Arman V.
• Primary Examiner(s): Griffin, Robert L.
• Assistant Examiner(s): Masinick, Michael Allen
• Application Number:
  US05/881,307
• Time in Patent Office: 974 Days
• Field of Search: 325/4, 325/5, 325/6, 325/7, 325/17, 325/20, 325/31, 325/51, 325/53, 325/54, 325/58, 325/63, 343/179, 178/69.1
• US Class Current: 455/517
• CPC Class Codes: H04L 7/0331 with a digital phase-locked loop [PLL] processing binary samples, e.g. add/subtract logic for correction of receiver clock H04L7/0337 takes precedence
• CPC Class Codes: H04W 56/001 Synchronization between nodes

Abstract

Digitally encoded data is carried over a first channel between a base station and a plurality of mobiles with the mobiles sharing a second channel for transmission to the base on a contention basis. Proper decoding of the data requires clock syncing at the receiver site.

To hasten clock recovery lock time at the base station and improve system throughput, each mobile includes apparatus for monitoring transmissions by the base station and deriving a transmit clock base for the mobile'"'"'s transmitter therefrom such that subsequent transmissions by the mobiles are all substantially in synchronization.

Claims

1. In a two-way communication system comprised of a base station and a plurality of mobile stations wherein the base station transmits to all mobiles over a first channel and the mobile stations transmit to the base station over a second channel and wherein the information carried by each transmission is encoded using a predetermined transmit clock signal, with proper decoding of each transmission requiring phase synchronization to said transmit clock signal, the improvement in a mobile station comprising:

a master oscillator for producing a signal of frequency kf_o at an output where k is a predetermined integer;

detector means for preparing said base station transmissions for decoding, and coupling a prepared signal to an output;

a clock recovery means, being coupled to the outputs from the master oscillator and the detector means, for producing a receiver clock signal which is phase locked to said prepared signal; and

means for utilizing the clock recovery means receiver clock signal as the transmit clock time base for an encoded transmission by said mobile station such that the transmission by said mobile station over said second channel is substantially synchronized to the base station transmission over the first channel.

2. The improvement of claim 1 wherein the receiver clock signal is also utilized by the receiver of said mobile station for decoding transmissions from said base station.

3. The improvement of claim 1 wherein said means for utilizing further comprises means operable during transmission by said mobile station for inhibiting the phase locking action of the clock recovery means.

4. In a radio communication system wherein a plurality of stations, each having a transmitter and a receiver, transmit and receive over provided channels, and wherein information signals are encoded at a clock frequency f_o for transmission over a channel, each station having a master oscillator for producing a signal of frequency kf_o, where k is a predetermined integer, and having a detector for preparing received transmissions for decoding, the improvement in a station comprising:

clock recovery means, coupled to the master oscillator and the detector, for producing an output signal which is phase locked to said prepared signal; and

means for utilizing the output signal of said clock recovery means as a transmitter encoding clock signal

5. The improvement of claim 4 wherein said means for utilizing further comprises means operable during transmission by said station to inhibit the phase locking action of the clock recovery means.