Synchronizing a telecommunications connection in a mobile communications system

• US 5,978,367 A
• Filed: 04/14/1997
• Issued: 11/02/1999
• Est. Priority Date: 08/14/1995
• Status: Expired due to Fees

• Current Assignee: Nokia Telecommunications Oy (Nokia Corporation)
• Original Assignee: Nokia Telecommunications Oy (Nokia Corporation)
• Inventors: Talarmo, Reino, Schroderus, Osmo, Kinnunen, Kimmo
• Primary Examiner(s): Nguyen, Chau
• Assistant Examiner(s): HYUN, SOON D
• Application Number:
  US08/817,798
• Time in Patent Office: 932 Days
• Field of Search: 370/276, 370/277, 370/278, 370/280, 370/313, 370/314, 370/327, 370/328, 370/329, 370/337, 370/340, 370/347, 370/465, 455/422, 455/426, 455/450, 455/455, 455/509, 455/524, 455/525, 455/526
• US Class Current: 370/337
• CPC Class Codes: H04B 7/2681 Synchronisation of a mobile station with one base station
• CPC Class Codes: H04W 56/0015 one node acting as a reference for the others
• CPC Class Codes: H04W 92/02 Inter-networking arrangements

Abstract

A method of synchronizing a telecommunications connection in a mobile communications system having at least one base station, and having a first and at least a second mobile station communicating on a direct mode channel, the first mobile station operating on the direct mode channel transmits a registration message to the base station of the mobile communications system on a system channel of the mobile communications system, the registration message indicating a wish of the first mobile station to operate in dual watch mode on the control channel of the mobile communications system. In response to the registration message, a specific control channel of the base station and the timing information related to the control channel are communicated to the first mobile station, the first mobile station switches to dual watch mode in order to communicate either on the direct mode channel or on the allocated control channel during the time indicated by the timing information.

Claims

1. A method for synchronizing a telecommunications connection in a mobile communications system having at least one base station communicating on system channels of the mobile communications system, these system channels including both at least one control channel and at least one traffic channel, and having a first mobile station arranged for communicating on a direct mode channel divided into frames consisting of time-slots, comprising the steps of:

transmitting from the first mobile station a registration message to a said base station of the mobile communications system on a system channel of the mobile communications system, by which registration message the first mobile station communicates a wish of the first mobile station to operate in dual watch mode on a control channel of the mobile communications system;

communicating by said base station to the first mobile station, in response to said registration message, identification of a specific control channel of the base station allocated for use by the first mobile station for operating in dual watch mode, and timing information related to synchronization of said specific control channel; and

the first mobile station, in response to said communicating, switching to dual watch mode for communicating alternatively on said direct mode channel and said specific control channel during times indicated by said timing information.

2. A method as claimed in claim 1, wherein:

said transmitting includes communicating from the first mobile station to said base station, in said registration message, information as to the direct mode channel on which said first mobile station wishes to operate in dual watch mode.

3. A method as claimed in claim 1, further comprising:

transmitting from the first mobile station synchronization information to one or more second mobile stations on said direct mode channel, said synchronization information containing timing information related to said specific control channel; and

shifting the start time of a frame of a time-slot of a direct mode channel transmission of at least one second mobile station with respect to the start time of a frame or a time-slot in accordance with the synchronization of said specific control channel of said mobile communications system, for achieving an adapted synchronization, which is adapted in accordance with said synchronization information transmitted by said first mobile station.

4. A method as claimed in claim 3, wherein:

said synchronization information contains an identifier for said mobile communications system.

5. A method as claimed in claim 4, wherein:

said transmitting of synchronization information includes transmitting from said first mobile station a transmission of said first mobile station in accordance with said adapted synchronization so that the start time of each frame according to the adapted synchronization to be transmitted on said direct mode channel is shifted with respect to the synchronization of said specific control channel such that a first time-slot according to the adapted synchronization coincides with a first uplink time-slot of said specific control channel.

6. A method as claimed in claim 5, wherein:

said transmitting of synchronization information includes transmitting from said first mobile station in accordance with said adapted synchronization such that the start time of each frame according to the adapted synchronization to be transmitted on said direct mode channel is shifted with respect to the synchronization of said specific control channel so that each frame according to the adapted synchronization of said direct mode channel coincides with a respective corresponding uplink frame of said specific control channel of the mobile communications system.

7. A method as claimed in claim 4, wherein:

said transmitting of synchronization information includes transmitting from said first mobile station in accordance with said adapted synchronization such that the start time of each frame according to the adapted synchronization to be transmitted on said direct mode channel is shifted with respect to the synchronization of said specific control channel so that each frame according to the adapted synchronization of said direct mode channel coincides with a respective corresponding uplink frame of said specific control channel of the mobile communications system.

11. A mobile communications system comprising:

at least one base station arranged for communicating on system channels of the mobile communications system, including on at least one control channel and on at least one traffic channel;

a first mobile station arranged for communicating on a direct mode channel divided into frames consisting of time-slots; and

communicating means for communicating on a specific said control channel of a said base station timing information related to said specific control channel, to said first mobile station, wherein;

said first mobile station is, in response to receiving from said communicating means an identifier identifying said specific control channel and said timing information, arranged to switch to dual watch mode for communicating alternatively on said direct mode channel and said specific control channel during a time indicated by said timing information.

12. A mobile station arranged for communicating on a direct mode channel divided into frames consisting of time-slots, comprising:

memory means;

a transceiver arranged to receive and transmit transmissions of said mobile station;

a controller for controlling operation of said mobile station; and

said transceiver including transmitter arranged for transmitting, to one or more second mobile stations on said direct mode channel, synchronization information containing an identifier of a mobile communications system used and an identifier of a specific control channel allocated to said mobile station, as well as timing information related to said control channel, wherein;

identifier of said specific control channel and said timing information are arranged to cause said one or more second mobile stations to switch to dual watch mode for communicating alternatively on said direct mode channel and specific control channel during a time indicated by said timing information.

13. A mobile station arranged for communicating on a direct mode channel divided into frames consisting of time-slots comprising:

memory means;

a transceiver arranged to receive and transmit transmissions of said mobile station;

a controller for controlling operation of said mobile station; and

said transceiver including transmitter arranged for transmitting, to one or more second mobile stations on said direct mode channel, synchronization information containing an identifier of a mobile communications system used and an identifier of a specific control channel allocated to said mobile station, as well as timing information related to said control channel,

a synchronization for shifting the start time of a frame or a time-slot of a transmission on said direct mode channel with respect to the start time of a frame or a time-slot in accordance with the synchronization of said specific control channel of said mobile communications system in response to the synchronization information transmitted by a second mobile station, or a base station or a repeater station of the mobile communications system.

8. A method as claimed in claim 13, wherein:

said transmitting of synchronization information includes transmitting from said first mobile station a transmission of said first mobile station in accordance with said adapted synchronization in such a way that frames in accordance with the adapted synchronization are shifted in order to each start a respective time-slot designated for the respective frame according to said synchronization information containing timing information related to said specific control channel of the mobile communications system.

9. A method as claimed in claim 8, wherein:

said transmitting of synchronization information includes transmitting from said first mobile station a transmission of said first mobile station in accordance with said adapted synchronization so that the start time of each frame according to the adapted synchronization to be transmitted on said direct mode channel is shifted with respect to the synchronization of said specific control channel such that a first time-slot according to the adapted synchronization coincides with a first uplink time-slot of said specific control channel.

10. A method as claimed in claim 8, wherein:

said transmitting of synchronization information includes transmitting from said first mobile station in accordance with said adapted synchronization such that the start time of each frame according to the adapted synchronization to be transmitted on said direct mode channel is shifted with respect to the synchronization of said specific control channel so that each frame according to the adapted synchronization of said direct mode channel coincides with a respective corresponding uplink frame of said specific control channel of the mobile communications system.

14. A mobile station as claimed in claim 13, wherein:

said memory means is arranged to store therein said synchronization information transmitted by said second mobile station, said base station or said repeater station of the mobile communications system and received by said transceiver, said synchronization information indicating the start time of a frame or a time-slot in accordance with an adapted synchronization with respect to start time of a TDMA frame or time-slot.

15. A mobile station arranged for communicating on a direct mode channel divided into frames consisting of time-slots, comprising:

memory means;

a transceiver arranged to receive and transmit transmissions of said mobile station,

a controller for controlling operation of said mobile station,

a synchronizator for shifting the start time of a frame or a time-slot of a transmission on said direct mode channel with respect to the start time of a frame or a time-slot in accordance with the synchronization of a specific control channel of a mobile communications system in response to the synchronization information transmitted by a second mobile station, or a base station or a repeater station of the mobile communications system, wherein;

said memory means is arranged to store therein said synchronization information transmitted by said second mobile station said base station or said repeater station of the mobile communications system and received by said transceiver, said synchronization information indicating the start time of a frame or a time-slot in accordance with the adapted synchronization with respect to a start time of a TDMA frame or time-slot.