Handover with mobile relays
First Claim
1. A handover method in a wireless communication system having a subscriber station (12), at least one base station (13) and a plurality of relay stations (14, MR_1′
- , MR_2), the subscriber station exchanging data traffic and signalling by employing wireless links with the base station (13), said wireless links including relay links which are indirect links between the subscriber station (12) and the base station (13) via one or more of the relay stations (14, MR_1′
, MR_2), the method comprising;
measuring a signal quality of each of a plurality of said wireless links;
determining a need for a handover of the subscriber station (12) from a serving relay station (MR_1′
) to another relay station (MR_2) by comparing the signal quality of a said relay link with a predetermined threshold and/or with the signal quality of another said wireless link; and
performing a handover of the subscriber station (12) from said serving relay station (MR 1′
) to said another relay station (MR_2);
characterised by;
employing, for control signalling between the subscriber station (12) and the base station (13), a said wireless link which is a direct link between the subscriber station and the base station; and
performing said handover for data traffic only whilst maintaining said direct link for control signalling.
1 Assignment
0 Petitions
Accused Products
Abstract
A method to provide mobility support of UEs (12) that are served by mobile relay base stations (14), by providing handover of a UE (12) for data traffic only between two mobile relay base stations. This is achieved by information exchanging between the source and target mobile relay stations of the concerned UE in handover, and/or the corresponding donor base stations (13, 11) if applicable. The handover is triggered by any of the following: based on UE'"'"'s measurement report, the signal quality of a neighbour cell is better than the current serving cell; based on the measurement of the serving mobile relay base station, the signal quality of the link to the UE is worse than a certain threshold; or based on the measurement of the serving mobile relay base station, the signal quality of a neighbour cell (potential donor base station) is much better than the current donor base station.
31 Citations
14 Claims
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1. A handover method in a wireless communication system having a subscriber station (12), at least one base station (13) and a plurality of relay stations (14, MR_1′
- , MR_2), the subscriber station exchanging data traffic and signalling by employing wireless links with the base station (13), said wireless links including relay links which are indirect links between the subscriber station (12) and the base station (13) via one or more of the relay stations (14, MR_1′
, MR_2), the method comprising;measuring a signal quality of each of a plurality of said wireless links; determining a need for a handover of the subscriber station (12) from a serving relay station (MR_1′
) to another relay station (MR_2) by comparing the signal quality of a said relay link with a predetermined threshold and/or with the signal quality of another said wireless link; andperforming a handover of the subscriber station (12) from said serving relay station (MR 1′
) to said another relay station (MR_2);
characterised by;employing, for control signalling between the subscriber station (12) and the base station (13), a said wireless link which is a direct link between the subscriber station and the base station; and performing said handover for data traffic only whilst maintaining said direct link for control signalling. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
- , MR_2), the subscriber station exchanging data traffic and signalling by employing wireless links with the base station (13), said wireless links including relay links which are indirect links between the subscriber station (12) and the base station (13) via one or more of the relay stations (14, MR_1′
-
11. A wireless communication system having a subscriber station (12), at least one base station (13) and a plurality of relay stations (14, MR_1′
- , MR_2), the subscriber station (12) arranged for exchanging data traffic and signalling by employing wireless links with the base station (13), said wireless links including relay links which are indirect links between the subscriber station (12) and the base station (13) via one or more of the relay stations (14, MR_1′
, MR_2), the system comprising;measurement means for measuring a signal quality of each of a plurality of said wireless links; handover determination means for determining a need for a handover of the subscriber station (12) from one relay station (MR_1′
) to another relay station (MR_2) by comparing the signal quality of a said wireless link with a predetermined threshold and/or with the signal quality of another said wireless link; andhandover performing means for performing a handover of the subscriber station (12) from said one relay station (MR_1′
) to said another relay station (MR_2);
characterised in that;the subscriber station (12) is arranged to employ a direct link between the subscriber station and the base station (13) for control signalling between the subscriber station and the base station; and said handover performing means is arranged for performing a handover for data traffic only whilst maintaining said direct link for control signalling. - View Dependent Claims (12, 13, 14)
- , MR_2), the subscriber station (12) arranged for exchanging data traffic and signalling by employing wireless links with the base station (13), said wireless links including relay links which are indirect links between the subscriber station (12) and the base station (13) via one or more of the relay stations (14, MR_1′
Specification