Arq parameter negotiation in a data packet transmission system using link adaptation

• US 20030092464A1
• Filed: 12/19/2002
• Published: 05/15/2003
• Est. Priority Date: 03/20/2000
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Li, Hui
• Granted Patent: US 7,266,086 B2
• Time in Patent Office: Days
• US Class Current: 455/78
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0019 in which mode-switching is based on a statistical approach
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/1809 Selective-repeat protocols
• CPC Class Codes: H04L 1/1832 Details of sliding window management
• CPC Class Codes: H04L 1/1835 Buffer management
• CPC Class Codes: H04L 1/187 Details of sliding window management
• CPC Class Codes: H04L 1/1874 Buffer management

Abstract

A method for transmitting data packets between a transmitter and a receiver unit in a communication system is described. For transmitting data packets a transmission mode is selected from a plurality of available transmission modes and an automatic repeat request for retransmission is used. Therefore for each available transmission mode a channel parameter based on link quality is calculated and a transmission capacity parameter is determinated. The state of the automatic repeat request control window for at least one transceiver is identified. For each available transmission mode an estimation of the user quality value based on the channel parameter, the transmission capacity parameter and the state of the automatic repeat request control window from at least one transceiver is estimated. The transmission mode that provides the best user quality value is selected.

Claims

1. Method for transmitting data packets between two transceivers in a communication system, wherein for transmitting data packets a transmission mode is selected from a plurality of available transmission modes and wherein an automatic repeat request for retransmission is used,

comprising the steps of:

calculating for each available transmission mode a channel parameter based on the link quality;

determinating for each transmission mode a transmission capacity parameter;

identifing the state of a automatic repeat request control window for at least one transceiver;

estimating a user quality value for each available transmission mode based on the channel parameter, the transmission capacity parameter and the state of the automatic repeat request control window from at least one transceiver; and

selecting a transmission mode that provides the best user quality value.

2. The method of claim 1, wherein

the channel parameter for each available transmission mode is the protocol data unit error rate PER_i.

3. The method of claim 1, wherein

the transmission capacity parameter is determined by at least the maximum data rate R_max provided in each available transmission mode.

4. The method of claim 3, wherein

the transmission capacity parameter is determined by the maximum data rate Rmaxi provided in each available transmission mode and the transmission time b and transmission frame length L provided for transmitting data packets.

5. The method of claim 1, wherein

in a transceiver which transmits data packets, the state of the automatic repeat request control window R_w is determined by the oldest protocol data unit sequence number TxBoW, the newest protocol data unit sequence number TxToW and the number of data packets Nt in the window which has to be retransmitted.

6. The method of claim 1, wherein

in a transceiver which receives data packets, the state of the automatic repeat request control window R_w is determined by the oldest protocol data unit sequence number RxBoW expected by the receiver unit, the newest protocol data unit sequence number RxToW received by the receiver unit and the number of data packets Nr in the window to be retransmitted.

7. The method according to any of the claims 1-6, wherein the user quality value for each available transmission mode is described by the user data throughput for that transmission mode T_i.

8. The method of claims 7, wherein

the step of estimating the user data throughput Ti bases on the protocol data unit error rate PER_i, the maximum data rate R_maxi, the transmission time b and transmission frame length L and the state of the ARQ control window R_w from at least one transceiver.

9. A communication system implemented the method according to any of the claims 1-8, wherein

the communication system is a radio packet data system.

10. A transceiver implemented the method according to any of the claims 1-9, wherein a controlling part in a transceiver includes:

a calculator for calculating a channel parameter based on the link quality,

a determinator for determinating a transmission capacity parameter for each available transmission mode,

an identifer for identifing the state of a automatic repeat request control window in at least one transceiver,

an estimator for estimating the user quality value for each available transmission mode based on the channel parameter, the transmission capacity parameter and the state of the automatic repeat request control window from at least one transceiver, and

a selector for selecting a transmission mode that provides the best user quality value.

11. Computer program executable by a controlling part of a transceiver, comprising software code portions for performing the steps of any of the claims 1-9.