Radio communication terminal, base station, handoff control method, and base station control method

• US 20070025295A1
• Filed: 05/31/2006
• Published: 02/01/2007
• Est. Priority Date: 05/31/2005
• Status: Active Grant

• Current Assignee: Kyocera Corporation
• Original Assignee: Kyocera Corporation
• Inventors: Kono, Kenji
• Granted Patent: US 8,725,147 B2
• Time in Patent Office: Days
• US Class Current: 370/331
• CPC Class Codes: H04W 36/0007 for multicast or broadcast services, e.g. MBMS multicast or broadcast application services H04W4/06; resource management for broadcast services H04W72/30; connection management for selective distribution or broadcast H04W76/40
• CPC Class Codes: H04W 36/0072 of resource information of target access point
• CPC Class Codes: H04W 36/02 Buffering or recovering information during reselection ; Modification of the traffic flow during hand-off
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 76/40 for selective distribution or broadcast

Abstract

A radio communication terminal (AT) includes a communication section for performing a radio communication with a base station, and a controller. Before performing a handoff from a first base station to another peripheral base station while receiving service information delivered by the first base station, the controller checks a progress of sequence of the service information being received. Then, the controller performs a handoff control depending on the check result. When it is determined that reception of a packet having the sequence number being received is to be completed within a certain time as a result of checking the progress, the controller suspends the handoff until the reception of the packet is completed.

Claims

1. A radio communication terminal comprising:

a receiver which receives a broadcast of at least one of a broadcast service and a multicast service; and

a controller which performs a handoff processing based on a completion state of reception of a packet which is in a layer higher than a radio communication layer, when a handoff is to be performed while the receiver receives the broadcast.

2. The radio communication terminal according to claim 1, wherein the controller suspends the handoff processing until the reception of the packet is completed.

3. The radio communication terminal according to claim 1, further comprising:

a transmitter,

wherein when the reception of the packet is completed, or when it takes equal to or more than a predetermined time to complete the reception of the packet, the controller performs a control so that the transmitter transmits a first message indicating the handoff is to be performed.

4. The radio communication terminal according to claim 3, wherein the first message includes identification information of the broadcast being received by the receiver, a sequence number of the packet being received, and information on a base station of a handoff destination.

5. The radio communication terminal according to claim 3, wherein when the receiver receives a second message specifying a time to perform the handoff, from a base station after the transmitter transmits the first message, the controller performs the handoff processing at the time specified in the second message.

6. A base station comprising:

a broadcasting section which performs a broadcast of at least one of a broadcast service and a multicast service;

a receiver which receives a first message indicating a handoff is to be performed from at least one radio communication terminal, the first message including identification information of the broadcast being received by the radio communication terminal, a sequence number of a packet which is in a layer higher than a radio communication layer received by the radio communication terminal, and information on a base station of a handoff destination;

a notifying section which notifies the base station of the handoff destination, of the identification information of the broadcast and the sequence number of the packet; and

a transmitter which transmits a second message indicating a time to perform the handoff to the radio communication terminal.

7. The base station according to claim 6, wherein

when the receiver receives the first message from each of the plurality of radio communication terminals, the transmitter transmits the second message indicating the time to perform the handoff being set based on the first message that is received the latest to each of the plurality of radio communication terminals.

8. A base station comprising:

a broadcasting section which performs a broadcast of at least one of a broadcast service and a multicast service;

a receiver which receives identification information of a broadcast being received by a radio communication terminal from another base station, and a sequence number of a packet which is in a layer higher than a radio communication layer received by the radio communication terminal; and

a controller which performs a control so that the broadcasting section performs the broadcast based on the received identification information and the received sequence number of the packet after a handoff of the radio communication terminal from the another base station is performed.

9. A handoff control method comprising:

receiving a broadcast of at least one of a broadcast service and a multicast service; and

performing a handoff processing based on a completion state of reception of a packet which is in a layer higher than a radio communication layer, when a handoff is to be performed while receiving the broadcast.

10. The handoff control method according to claim 9, further comprising:

suspending the handoff processing until the reception of the packet is completed.

11. The handoff control method according to claim 9, further comprising:

transmitting a first message indicating the handoff is to be performed, when the reception of the packet is completed, or when it takes equal to or more than a predetermined time to complete the reception of the packet.

12. The handoff control method according to claim 11, wherein the first message includes identification information of the broadcast being received, a sequence number of the packet being received, and information on a base station of a handoff destination.

13. The handoff control method according to claim 11, wherein when a second message specifying a time to perform the handoff is received from a base station after transmitting the first message, the handoff processing is performed at the time specified in the second message.

14. A base station control method comprising:

performing a broadcast of at least one of a broadcast service and a multicast service;

receiving a first message indicating a handoff is to be performed from at least one radio communication terminal that is receiving the broadcast, the first message including identification information of the broadcast being received by the radio communication terminal, a sequence number of a packet which is in a layer higher than a radio communication layer received by the radio communication terminal, and information on a base station of a handoff destination;

notifying the base station of the handoff destination, of the identification information of the broadcast and the sequence number of the packet; and

transmitting a second message indicating a time to perform the handoff to the radio communication terminal.

15. The base station control method according to claim 14, wherein

when the first message is received from each of the plurality of radio communication terminals, the second message indicating the time to perform the handoff being set based on the first message that is received the latest is transmitted to each of the plurality of radio communication terminals.

16. A base station control method comprising:

performing a broadcast of at least one of a broadcast service and a multicast service; and

receiving identification information of a broadcast being received by a radio communication terminal from another base station, and a sequence number of a packet which is in a layer higher than a radio communication layer received by the radio communication terminal,

wherein the broadcast is performed based on the received identification information and the received sequence number of the packet after a handoff of the radio communication terminal from the another base station is performed.