RETRANSMISSION CONTROL METHOD, BASE STATION AND MOBILE STATION

• US 20090052392A1
• Filed: 01/19/2006
• Published: 02/26/2009
• Est. Priority Date: 02/15/2005
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Kimura, Ryohei, Naka, Katsuyoshi, Hoshino, Masayuki, Sumasu, Atsushi, Yamazaki, Junya, Haga, Hiroki, Kayama, Hidenori
• Granted Patent: US 8,711,804 B2
• Time in Patent Office: Days
• US Class Current: 370/331
• CPC Class Codes: H04L 1/1887 Scheduling and prioritising arrangements
• CPC Class Codes: H04W 36/02 Buffering or recovering information during reselection ; Modification of the traffic flow during hand-off

Abstract

A base station, a mobile station and a retransmission control method for enabling communication to be more efficiently performed. In a communication system comprising a base station (100) and a mobile station (200), a time period required for the retransmission of a transport packet to complete is determined, and a retransmission control is performed, based on the required time period, to change the order of executing the retransmission of the transport packet and a handover. In this way, when it is estimated that the retransmission will complete soon, the retransmission is caused to complete in a handover source system, thereby avoiding waste of communication resources used in the preceding transmission and retransmission processes. When it is estimated that the retransmission will continue for a while, the communication resources used in the preceding transmission and retransmission processes are wasted, but a more appropriate MCS can be assigned, in a handover destination system, so as to perform a retransmission, thereby enabling communication to be efficiently performed.

Claims

1. A retransmission control method comprising the steps of:

acquiring the time required to complete a retransmission of a transmission packet; and

changing an execution order of the transmission of the transmission packet and a handover, based on the required time.

2. The retransmission control method according to claim 1, wherein the step of changing the execution order comprises the steps of:

completing the retransmission of the transmission packet at a handover source system when the required time is equal to or greater than a predetermined threshold value, and then executing the handover; and

executing the retransmission of the transmission packet at a handover destination system when the required time is less than the predetermined threshold value.

3. The retransmission control method according to claim 1, wherein, in the step of changing the execution order, the retransmission of the transmission packet is executed before the handover when a number of retransmissions, the number of retransmissions normalized by a maximum number of retransmissions, or the number of retransmissions normalized by an average number of retransmissions, as an index for the time required to complete retransmission corresponding to the required time, is equal to or less than a threshold value.

4. A base station comprising a plurality of different systems that perform communication with a mobile station, the base station comprising:

a packet generating section that generates a transmission packet and retains the transmission packet; and

a control section that controls a retransmission of the transmission packet based on a retransmission request from the mobile station, and that controls handovers between the systems based on a handover request from the mobile stations,

wherein the control section changes the order of execution of the retransmission transmission packets and a handover, based on the required time to complete the retransmission of the transmission packet.

5. The base station according to claim 4, wherein the control section executes the retransmission of the transmission packet before the handover when the number of retransmissions, the number of retransmissions normalized by the maximum number of retransmissions, or the number of retransmissions normalized by the average number of retransmissions, as an index for the time required to complete the retransmission corresponding to the required time, is equal to or less than the threshold value.

6. The base station according to claim 4, wherein:

H-ARQ is applied as a retransmission control method for the transmission packet; and

the control section executes the retransmission of the transmission packet before the handover when a full received power to noise power ratio obtained by sequentially adding the received power to noise power ratios of the same packet, as the index for the time required to complete the retransmission corresponding to the required time, is equal to or less than a predetermined threshold value.

7. A mobile station capable of communications with a plurality of systems, the mobile station comprising:

a radio quality measuring section that measures a radio quality between the mobile station and the systems;

a generating section that generates are transmission request signal for a packet based on an error detection result of the packet;

a signal generating section that generates a handover request signal for requesting a handover between the systems, according to the radio quality; and

a control section that changes an order of an execution of the transmission of the transmission packet retransmission request signal and the transmission of the handover request signal, based on the required time to complete the retransmission of the transmission packet.

8. The mobile station according to claim 7, wherein the control section executes a transmission of a retransmission request signal of the transmission packet before the handover request signal, when the number of retransmissions, the number of retransmissions normalized by the maximum number of retransmissions, or the number of retransmissions normalized by the average number of retransmissions, as an index for the time required to complete retransmission corresponding to the required time, is equal to or less than a predetermined threshold value.