Synchronizing a telecommunication connection in a mobile communication system

• US 5,943,326 A
• Filed: 09/19/1996
• Issued: 08/24/1999
• Est. Priority Date: 01/19/1995
• Status: Expired due to Fees

• Current Assignee: Cassidian Finland OY
• Original Assignee: Nokia Telecommunications Oy (Nokia Corporation)
• Inventors: Schroderus, Osmo
• Primary Examiner(s): Pham, Chi H.
• Assistant Examiner(s): YAO, KWANG BIN
• Application Number:
  US08/716,375
• Time in Patent Office: 1,069 Days
• Field of Search: 370/315, 370/316, 370/319, 370/321, 370/322, 370/323, 370/324, 370/326, 370/327, 370/328, 370/336, 370/337, 370/345, 370/347, 370/348, 370/350, 455/422, 455/424, 455/425, 455/502, 455/507, 455/515, 455/517
• US Class Current: 370/324
• CPC Class Codes: H04B 7/155 Ground-based stations H04B7/204 takes precedence
• CPC Class Codes: H04B 7/2606 Arrangements for base station coverage control, e.g. by using relays in tunnels
• CPC Class Codes: H04J 3/0682 by delay compensation, e.g. by compensation of propagation delay or variations thereof, by ranging
• CPC Class Codes: H04W 56/002 Mutual synchronization
• CPC Class Codes: H04W 76/10 Connection setup
• CPC Class Codes: H04W 92/10 between terminal device and access point, i.e. wireless air interface

Abstract

A method for synchronizing a telecommunication connection in a mobile communication system, in which method a repeater station receives a connection set-up request for establishing a telecommunication connection from a mobile station communicating on a direct mode channel to the mobile communication system, and in which the repeater station receives traffic channel information concerning on which traffic channel of the mobile communication system the telecommunication connection to be established must be established. In the method, the repeater station notifies the mobile stations communicating on the direct mode channel, on the basis of the traffic channel information, of synchronization information concerning the adaptive synchronization to be used over the telecommunication connection to be established on the direct mode channel, and that a mobile station shifts the starting moment of a frame of its own direct mode channel transmission in relation to the starting moment according to the basic synchronization in accordance with the adaptive synchronization indicated in the synchronization information notified by the repeater station.

Claims

1. A method for synchronizing a telecommunication connection in a mobile communication system, which includes a base station which communicates on system control and traffic channels of the mobile communication system, uplink and downlink frequencies of said system channels being divided into frames including time slots, a direct mode mobile station communicating by transmission on a single frequency direct mode channel divided into frames including time slots, said direct mode mobile station being arranged to synchronize its transmission with a basic synchronization converging with a synchronization of a downlink frame of a system control channel of said base station, and a direct mode relay repeater which communicates with said direct mode mobile station communicating on the direct mode channel and with said base station, said method comprising:

said direct mode mobile station communicating with at least one other direct mode mobile station on said single frequency direct mode channel;

said direct mode relay repeater receiving a connection set-up request for establishing a telecommunication connection between said direct mode mobile station communicating on said direct mode channel and said mobile communication system;

said direct mode relay repeater receiving, from said mobile communication system over said system control channel, traffic channel information concerning on which of said traffic channels of said mobile communication system said telecommunication connection to be established must be established, as an allocated traffic channel;

said direct mode relay repeater notifying said direct mode mobile station on said direct mode channel, based on said traffic channel information, of synchronization information concerning an adaptive synchronization to be used over said telecommunication connection to be established on said direct mode channel; and

said direct mode mobile station shifting a starting moment of a frame of its own direct mode channel transmission in relation to a starting moment according to said basic synchronization in accordance with said adaptive synchronization indicated in the synchronization information sent to said direct mode mobile station by the direct mode relay repeater.

2. A method according to claim 1, wherein:

said shifting is conducted such that said direct mode mobile station transmits according to said adaptive synchronization in such a manner that a frame of adaptive synchronization is shifted to start at a desired time slot of a frame of said basic synchronization.

3. A method according to claim 2, wherein:

said shifting is conducted such that said direct mode mobile station transmits according to said adaptive synchronization in such a manner that a frame of said adaptive synchronization is shifted to start in relation to said basic synchronization in such a manner that a first time slot of said adaptive synchronization is simultaneous with an uplink time slot of said traffic channel allocated to said telecommunication connection.

4. A method according to claim 1, wherein:

said shifting is conducted such that said direct mode mobile station transmits according to said adaptive synchronization in such a manner that a frame of said adaptive synchronization is shifted to start in relation to said basic synchronization in such a manner that a first time slot of said adaptive synchronization is simultaneous with an uplink time slot of said traffic channel allocated to said telecommunication connection.

5. A method according to claim 1, wherein:

said shifting is conducted such that direct mode mobile station transmits according to said adaptive synchronization in such a manner that a frame of said adaptive synchronization is shifted to start in relation to the basic synchronization in such a manner that the frame of said adaptive synchronization is simultaneous with a downlink frame of said control channel of said base station.

6. A method according to claim 1, wherein:

said notifying includes said direct mode relay repeater changing the synchronization of the frame of said direct mode mobile station operating on said direct mode channel by transmitting synchronization information to said direct mode mobile station indicating a location of a frame of said adaptive synchronization in relation to a frame of said basic synchronization, in time domain.

7. A method according to claim 1, wherein:

in said receiving a connection set-up request, said direct mode relay repeater receives said connection setup request from said base station.

8. A method according to claim 1, wherein:

in said receiving a connection set-up request, said direct mode relay repeater receives said connection set-up request from said direct mode mobile station communicating on said direct mode channel.

9. A mobile communication system, comprising:

at least one base station arranged to communicate on system control and traffic channels of the mobile communication system, said system channels having uplink and downlink frequencies which are divided into frames including time slots;

at least one direct mode mobile station arranged to communicate by transmission on a single frequency direct mode channel divided into frames including time slots, each of said at least one direct mode mobile station being arranged to synchronize its respective transmission with a basic synchronization converging with the synchronization of the system control channel of a respective said base station;

a direct mode relay repeater, arranged to communicate with said at least one mobile station on said direct mode channel and with said at least one base station on said system channels, said direct mode relay repeater comprising;

a first receiver unit for receiving radio messages from said at least one base station and said system channels;

a second, direct mode, receiver unit for receiving radio messages from said at least one direct mode mobile station communicating on said direct mode channel;

a control unit for controlling operation of said direct mode relay repeater; and

at least one transmitter unit for transmitting radio messages in response to commands given by said control unit selectively at least to said at least one base station on said system channels and to said at least one direct mode mobile station on said direct mode channel;

said direct mode relay repeater being arranged to notify said at least one direct mode mobile station on said direct mode channel, based on traffic channel information allocated to a telecommunication connection to be established, of synchronization information concerning an adaptive synchronization to be used over said telecommunication connection to be established on said direct mode channel, said at least one direct mode mobile station being arranged to shift, in response to said synchronization information, a starting moment of its respective own direct mode channel transmission in relation to a starting moment according to said synchronization information.

10. A mobile communication system according to claim 9, wherein:

said direct mode relay repeater comprises means for transmitting said synchronization information to said at least one direct mode mobile station operating on said direct mode channel, said synchronization information indicating said adaptive synchronization to be used on said telecommunication connection.

11. A direct mode mobile station communicating by transmission on a single frequency direct mode channel divided into frames including time slots, said direct mode mobile station being arranged to synchronize a starting moment of a frame of said direct mode channel transmission with a basic synchronization converging with a synchronization of a control channel of a base station, said direct mode mobile station comprising:

a memory;

a transceiver, which is arranged to transmit and receive on said direct mode channel to and from at least one other direct mode mobile station without monitoring system channels;

a control unit for controlling an operation of the direct mode mobile station;

said direct mode mobile station being arranged to shift, in response to synchronization information, obtained from a direct mode relay repeater monitoring said system channels, a starting moment of a frame of said direct mode channel transmission of said direct mode mobile station in relation to a starting moment according to said basic synchronization, in accordance with an adaptive synchronization indicated in synchronization information sent to said direct mode mobile station by the direct mode relay repeater.

12. A direct mode mobile station according to claim 11, wherein:

said direct mode mobile station is arranged to store in said memory said synchronization information obtained from the direct mode relay repeater, said synchronization information indicating a starting moment of a frame according to said adaptive synchronization in comparison with a starting moment of a frame according to said basic synchronization.

13. A direct mode mobile station according to claim 11, wherein:

said direct mode mobile station is arranged to store in said memory said synchronization information received from the direct mode relay repeater, said synchronization information indicating a starting moment of a frame according to said adaptive synchronization in comparison with a starting moment of a frame according to said basic synchronization.

14. A direct mode relay repeater which is arranged to communicate with direct mode mobile stations communicating on a single frequency direct mode channel and with a base station of a mobile communication system on system control and traffic channels having uplink and downlink frequencies, said direct mode relay repeater station comprising:

a first receiver unit for receiving radio messages on said system channels from said base station;

a second, direct mode receiver unit for receiving radio messages from the direct mode mobile stations on said direct mode channel;

a control unit for controlling operation of said direct mode relay repeater;

at least one transmitter unit for transmitting radio messages in response to commands given by said control unit selectively at least to said base station on said system channels and to a respective one of said direct mode mobile stations on the direct mode channel;

said direct mode repeater station being arranged to notify said one of said direct mode mobile stations communicating on the direct mode channel, based on traffic channel information allocated to a telecommunication connection to be established, of synchronization information concerning an adaptive synchronization to be used over said telecommunication connection on said direct mode channel, for causing said one of said direct mode mobile stations to shift, in response to said synchronization information, a starting moment of a direct mode channel transmission of said one of said direct mode mobile stations in accordance with said adaptive synchronization indicated in said synchronization information sent to said one of said direct mode mobile stations by said direct mode relay repeater.

15. A direct mode relay repeater according to claim 14, wherein:

said at least one transmitter unit includes means for transmitting said synchronization information to the respective one of said direct mode mobile stations operating on the direct mode channel, said synchronization information indicating said adaptive synchronization to be used on said telecommunication connection.

16. A method for synchronizing a telecommunication connection in a mobile communication system, which includes a base station which communicates on system control and traffic channels of the mobile communication system, uplink and downlink frequencies of said system channels being divided into frames including time slots, a direct mode mobile station communicating by transmission on a single frequency direct mode channel divided into frames containing time slots, said direct mode mobile station being arranged to synchronize a transmission of said direct mode mobile station with a basic synchronization converging with a synchronization of a downlink frame of a system control channel of said base station, and a direct mode relay repeater which communicates with said direct mode mobile station communicating on the direct mode channel and with said base station on said system control and traffic channels, said method comprising:

said direct mode mobile station communicating with at least one other direct mode mobile station on said single frequency direct mode channel;

said direct mode relay repeater receiving a connection set-up request for establishing a telecommunication connection between said direct mode mobile station communicating on said direct mode channel and said mobile communication system;

said direct mode relay repeater receiving from said mobile communication system, over said system control channel, traffic channel information concerning on which system traffic channel of said mobile communication system said telecommunication connection to be established must be established, as an allocated traffic channel;

said direct mode relay repeater notifying said direct mode mobile station on said direct mode channel, based on said traffic channel information, of synchronization information concerning an adaptive synchronization to be used over said telecommunication connection to be established on said direct mode channel; and

said direct mode mobile station shifting a starting moment of a frame of a direct mode channel transmission of said direct mode mobile station in relation to a starting moment according to said basic synchronization in accordance with said adaptive synchronization indicated in the synchronization information sent to said direct mode mobile station by the direct mode relay repeater, so that a first time slot of each direct mode channel frame is aligned with an uplink time slot of said allocated traffic channel.

17. A mobile communication system comprising:

at least one base station arranged to communicate on system control and traffic channels of the mobile communication system, said system channels having uplink and downlink frequencies which are divided into frames containing time slots;

at least one direct mode mobile station arranged to communicate by transmission on a single frequency direct mode channel divided into frames containing time slots, each of said at least one direct mode mobile station being arranged to synchronize its respective transmission with a basic synchronization converging with a synchronization of a control channel of a respective one of said at least one base station;

a direct mode relay repeater, arranged to communicate with said at least one direct mobile station on said direct mode channel and with said at least one base station on said system channels, said direct mode relay repeater comprising;

a first receiver unit for receiving radio messages from said at least one base station on said system channels;

a second, direct mode, receiver unit for receiving radio messages from said at least one direct mode mobile station on said direct mode channel;

a control unit for controlling operation of said direct mode relay repeater; and

at least one transmitter unit for transmitting radio messages in response to commands given by said control unit selectively at least to said at least one base station on said system channels and to said at least one direct mode mobile station on said direct mode channel;

said direct mode relay repeater being arranged to notify said at least one direct mode mobile station on said direct mode channel, based on traffic channel information allocated to a telecommunication connection to be established, of synchronization information concerning an adaptive synchronization to be used over said telecommunication connection to be established on said direct mode channel,

said at least one direct mode mobile station being arranged to shift, in response to said synchronization information, a starting moment of its respective own direct mode channel transmission in relation to a starting moment according to said synchronization information so that a first time slot of each direct mode channel frame is aligned with an uplink time slot of said allocated traffic channel,

said second receiver unit of said direct mode repeater being arranged to receive said direct mode channel transmission of said at least one direct mode mobile station in said first time slot of a respective current direct mode channel frame and said transmitter of said direct mode repeater being arranged to simultaneously retransmit a direct mode channel transmission, receive in said first time slot of respective previous direct mode channel frame, to said mobile communications system in said uplink time slot of said allocated traffic channel.

18. A direct mode relay repeater arranged to communicate with direct mode mobile stations communicating on a single frequency direct mode channel and with a base station of a mobile communication system on system control and traffic channels having uplink and downlink frequencies, said direct mode relay repeater comprising:

a first receiver unit for receiving radio messages on said system channels from said base station;

a second, direct mode receiver unit for receiving radio messages from the direct mode mobile stations on said direct mode channel;

a control unit for controlling operation of said direct mode relay repeater; and

at least one transmitter unit for transmitting radio messages in response to commands given by said control unit selectively at least to said base station on said system channels and to a respective one of said direct mode mobile stations on the direct mode channel;

said direct mode repeater being arranged to notify said direct mode mobile stations on the direct mode channel, based on traffic channel information allocated to a telecommunication connection to be established, of synchronization information concerning an adaptive synchronization to be used over said telecommunication connection on said direct mode channel, for causing said direct mode mobile stations to shift, in response to said synchronization information, the starting moment of its own direct mode channel transmission in accordance with said adaptive synchronization indicated in said synchronization information sent to said direct mode mobile stations by said direct mode relay repeater, so that a first time slot of each direct mode channel frame is aligned with an uplink time slot of said allocated traffic channel,

said second receiver unit of said direct mode repeater being arranged to receive said direct mode channel transmission of said direct mode mobile stations in said first time slot of respective current direct mode channel frame and said transmitter of said direct mode repeater being arranged to simultaneously retransmit a direct mode channel transmission, received in said first time slot of respective previous direct mode channel frame, to said mobile communications system in said uplink time slot of said allocated traffic channel.

19. A mobile communication system comprising:

a base station arranged to communicate on system control and traffic channels of said mobile communication system, uplink and downlink frequencies of said system channels being divided into frames including time slots;

a direct mode mobile station arranged to communicate by transmission on a single frequency direct mode channel divided into frames including time slots, said direct mode mobile station being arranged to synchronize its transmission with a basic synchronization converging with a synchronization of a downlink frame of a system control channel of said base station; and

a direct mode relay repeater arranged to communicate with said direct mode mobile station communicating on said direct mode channel and with said base station on said system control channel and said traffic channel, wherein;

said direct mode mobile station being arranged to communicate with at least one other direct mode mobile station on said single frequency direct mode channel,

said direct mode relay repeater being arranged to receive a connection setup request for establishing a telecommunication connection between said direct mode mobile station communicating on said direct mode channel and said mobile communication system,

said direct mode relay repeater being arranged to receive from said mobile communication system, over said system control channel, traffic channel information concerning on which system traffic channel of said mobile communication system said telecommunication connection to be established must be established, as an allocated traffic channel;

said direct mode relay repeater being arranged to notify said direct mode mobile station on said direct mode channel, based on said traffic channel information, of synchronization information concerning an adaptive synchronization to be used over said telecommunication connection to be established on said direct mode channel;

said direct mode mobile station being arranged to shift a starting moment of a frame of its own direct mode channel transmission in relation to a starting moment according to a basic synchronization in accordance with said adaptive synchronization indicated in the synchronization information sent to said direct mode mobile station by the direct mode relay repeater, so that a first time slot of each direct mode channel frame is aligned with an uplink time slot of said allocated traffic channel; and

said direct mode repeater receiving said direct mode channel transmission of said direct mode mobile station and retransmitting said received transmission on said system traffic channel to said mobile communications system.