Method of transmitting timing advance data to a mobile station in a cellular mobile radio network and corresponding mobile station, base station controller and transmission system

A method of exchanging information in a cellular mobile radio network between a mobile station (MS), at least first and second base transceiver stations (BTS1, BTS2), first and second base station controllers (BSC1, BSC2) respectively controlling said at least first and second base transceiver stations (BTS1, BTS2), and a mobile services switching center (MSC) controlling said first and second base station controllers (BSC1, BSC2), said exchanges of information between said mobile station and said at least first and second base transceiver stations (BTS1, BTS2) being time-division multiple access exchanges, said method comprising the steps of:

• transmitting an instruction (HO CHN) from said first base station controller (BSC1) to said mobile station (MS) telling said mobile station (MS) to interrupt communication with said first base transceiver station (BTS1) with which said mobile station (MS) is communicating in order to send a first sequence of synchronization signals (HO ACCESS) to said second base transceiver station (BTS2) enabling said second base transceiver station (BTS2) to calculate a timing advance (TA), said instruction (HO CHN) being transmitted when said mobile station (MS) moves from a first cell (C1) defined by the geographical coverage area of said first base transceiver station (BTS1) to a second cell (C2) defined by the geographical coverage area of said second base transceiver station (BTS2),
• said instruction (HO CHN) supplied to said mobile station (MS) also indicates that said mobile station (MS) must continue to communicate with said first base transceiver station (BTS1) immediately after sending said first sequence of synchronization signals (HO ACCESS) to said second base transceiver station (BTS2),
• transmitting said calculated timing advance (TA) from said second base transceiver station (BTS2) to said second base station controller (BSC2),
• transmitting said calculated timing advance (TA) from said second controller (BSC2) to said mobile services switching center (MSC),
• transmitting said calculated timing advance (TA) from said mobile services switching center (MSC) to said first base station controller (BSC1), and
• transmitting said calculated timing advance (TA) from said first base station controller (BSC1) to said mobile station (MS) via to said first base transceiver station (BTS1), said mobile station (MS) communicating With said second base transceiver station (BTS2) in accordance with said timing advance (TA).

A mobile station (MS) adapted to communicate by time-division multiple access with at least first and second base transceiver stations (BTS1,BTS2) of a cellular mobile radio network, said mobile station (MS) comprising:

• signal transceiver means (60, 65) for receiving a timing advance (TA) from said first base transceiver station (BTS1) when said mobile station moves from a first cell (C1), defined by the geographical coverage area of said first base transceiver station (BTS1) with which said mobile station (MS) is communicating, to a second cell (C2), defined by the geographical coverage area of said second base transceiver station (BTS2),
• means (61), coupled to said signal transceiver means (60,65), for detecting an instruction (HO CHN) transmitted to said mobile station (MS) by said first base transceiver station (BTS1) and which instructs said mobile station (MS) to interrupt communication with said first base transceiver station (BTS1) and to send a first sequence of synchronization signals (HO ACCESS) to said second base transceiver station (BTS2) to enable said second base transceiver station (BTS2) to calculate a timing advance (TA), said instruction (HO CHN) also instructing said mobile station (MS) to continue communicating with said first base transceiver station (BTS1) immediately after sending said first sequence of synchronization signals (HO ACCESS) to said second base transceiver station (BTS2), and
• means (62), coupled to said instruction detecting means (61), for detecting a control signal (HO CMD (TA)) transmitted to said mobile station (MS) by said first base transceiver station (BTS1) and containing said timing advance (TA), said control signal instructing said mobile station (MS) to communicate with said second base transceiver station (BTS2) in accordance with said timing advance (TA).

A system for exchanging information between a mobile station (MS), at least first and second base transceiver stations (BTS1, BTS2), and a base station controller (BSC) for said at least first and second base transceiver stations (BTS1, BTS2), exchanges of said information between said mobile station (MS) and said at least first and second base transceiver stations (BTS1, BTS2) being time-division multiple access exchanges, said mobile station (MS) comprising means (61) for detecting an instruction (HO CHN) when said mobile station moves from a first cell (C1) defined by the geographical coverage area of said first base transceiver station (BTS1) with which said mobile station (MS) is communicating to a second cell (C2) defined by the geographical coverage area of said second base transceiver station (BTS2), said instruction (HO CHN) instructing said mobile station (MS) to send a sequence of synchronization signals (HO ACCESS) to said second base transceiver station (BTS2) which comprises means (71) for calculating, based on receipt of said synchronization signals (HO ACCESS), a timing advance (TA) to be supplied to said mobile station (MS), said mobile station (MS) continuing to communicate with said first base transceiver station (BTS1) immediately after sending said sequence of synchronization signals (HO ACCESS) to said second base transceiver station (BTS2),

• said second base transceiver station (BTS2) further including means (70) for sending said calculated timing advance (TA) to said controller (BSC), said base station controller (BSC) comprising means (80) for sending said calculated timing advance (TA) to said first base transceiver station (BTS1),
• and said first base transceiver station (BTS1) comprising means (70) for forwarding said calculated timing advance (TA) to said mobile station (MS), said mobile station (MS) communicating with said second base transceiver station (BTS2) in accordance with said timing advance (TA).

A system for exchanging information in a cellular mobile radio network between a mobile station (MS), a first base transceiver station (BTS1) associated with a first base station controller (BSC1), and a second base transceiver station (BTS2) associated with a second base station controller (BTS2), said first and second base station controllers (BSC1, BSC2) being controlled by a mobile services switching center (MSC), said exchanges of said information between said mobile station (MS) and said first and second base transceiver stations (BTS1, BTS2) being time-division multiple access exchanges, said mobile station (MS) comprising means (51) for detecting an instruction (HO CHN) from said first base transceiver station (BTS1) when said mobile station (MS) moves from a first cell (C1) defined by the geographical coverage area of said first base transceiver station (BTS1) with which said mobile station (MS) is communicating to a second cell (C2) defined by the geographical coverage area of said second base transceiver station (BTS2), said instruction (HO CHN) instructing said mobile station (MS) to send a sequence of synchronization signals (HO ACCESS) to said second base transceiver station (BTS2) which comprises means for calculating, based on receipt of said sequence of synchronization signals (HO ACCESS), a timing advance (TA) to be supplied to said mobile station (MS), said mobile station (MS) continuing to communicate with said first base transceiver station (BTS1) immediately after sending said sequence of synchronization signals (HO ACCESS) to said second base transceiver station (BTS2), said second base transceiver station (BTS2) further comprising means (70) for sending said calculated timing advance (TA) to said switching center (MSC) via said second base station controller (BSC2),

• said switching center (MSC) comprising means (90) for sending said calculated timing advance (TA) to said first base station controller (BSC1),
• said first base station controller (BSC1) comprising means (80) for sending said calculated timing advance (TA) to said first base transceiver station (BTS1), and said first base transceiver station (BTS1) comprising means (70) for forwarding said calculated timing advance (TA) to said mobile station (MS), said mobile station (MS) communicating with said second base transceiver station (BTS2) in accordance with said timing advance (TA).