Data transmission method combating degradation of the quality of service

• US 20020021714A1
• Filed: 04/04/2001
• Published: 02/21/2002
• Est. Priority Date: 05/25/2000
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Seguin, Laure
• Granted Patent: US 7,206,295 B2
• Time in Patent Office: Days
• US Class Current: 370/469
• CPC Class Codes: H04L 1/0007 by modifying the frame length
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/0029 Reduction of the amount of signalling, e.g. retention of useful signalling or differential signalling power control H04W52/04
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/36 by determining packet size, e.g. maximum transfer unit [MTU]
• CPC Class Codes: H04L 69/32 Architecture of open systems interconnection [OSI] 7-layer type protocol stacks, e.g. the interfaces between the data link level and the physical level
• CPC Class Codes: H04L 69/324 in the data link layer [OSI layer 2], e.g. HDLC
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04W 52/04 TPC

Abstract

The present invention relates to a method of transmitting data on a physical resource using

a layer (RRC) responsible for the management of the physical resource and the guarantee of the quality of service;

a sub-layer (RLC) responsible for supplying a transmission support in accordance with the required quality of service;

a sub-layer (MAC) responsible for access to the physical resource;

a physical layer (PHY) responsible for the physical processing of the data;

access to the physical resource being divided into transmission time intervals (TTI);

the sub-layer (RLC) being able to segment the data into transmission units (RLC PDU);

the sub-layer (MAC) being able to transmit at least one transmission unit per transmission time interval;

characterised in that, in the event of degradation of the transmission conditions on the physical resource, the size of the transmission units is reduced.

Claims

1. Method of transmitting data on a physical resource using

a layer (RRC) responsible for the management of the physical resource and the guarantee of the quality of service;

a sub-layer (RLC) responsible for supplying a transmission support in accordance with the required quality of service;

a sub-layer (MAC) responsible for access to the physical resource;

a physical layer (PHY) responsible for the physical processing of the data;

access to the physical resource being divided into transmission time intervals (TTI);

the sub-layer (RLC) being able to segment the data into transmission units (RLC PDU);

the sub-layer (mac) being able to transmit at least one transmission unit per transmission time interval;

characterised in that, in the event of degradation of the transmission conditions on the physical resource, the size of the transmission units is reduced;

2. Data transmission method according to claim 1, characterised in that, at the start of a connection between a transmitter and receiver accessing the physical resource, the layer (RRC) determines a plurality of possible transmission unit sizes for a transmission time interval (TTI) and in that the sub-layer (MAC) selects, from amongst this plurality, a transmission unit size according to the transmission conditions, a smaller size being selected in the case of degradation of the transmission conditions on the physical resource.

3. Data transmission method according to claim 1, characterised in that, at the start of a connection between a transmitter and receiver accessing the physical resource, the layer (RRC) fixes a first size of transmission unit (RLC PDU) according to the transmission conditions and transmits it to the sub-layer (MAC).

4. Data transmission method according to claim 3, characterised in that, in the case of degradation of the transmission conditions on the physical resource, the layer (RRC) fixes a second size of transmission unit (RLC PDU) less than the first and transmits it to the sub-layer (MAC).

5. Data transmission method according to one of claims 1 to 4, characterised in that the layer (RRC) guarantees a quality of service by assigning a set level SIR_t to the ratio of received signal power to noise plus interference;

in the case of degradation of the transmission conditions the transmission power of the transmitter is increased so as to maintain the quality of service;

the size of the transmission unit (RLC PDU) is reduced when the transmission power reaches a maximum value.

6. Data transmission method according to claims 4 and 5, characterised in that the layer (RRC) allocates resources by lowering the set level SIR_t of a service according to the inverse of its degree of priority.

7. Data transmission method according to one of the preceding claims, characterised in that the layer (RLC) functions in acknowledged mode, a transmission unit being retransmitted if the acknowledgement is not received.

8. UMTS mobile telephony system using a data transmission method according to one of the preceding claims.

9. Mobile telephony system according to claim 8 using a data transmission method according to claim 2, characterised in that the layer (RRC) supplies to the sub-layer (MAC) the plurality of possible sizes by means of the TFCS table.

10. Mobile telephony system according to claim 8 using a data transmission method according to claim 4, characterised in that the layer (RRC) fixes a second size for the transmission unit by sending a new TFCS table to the sub-layer (MAC).