Method and device of dynamic resource allocation in a wireless network

• US 20050249114A1
• Filed: 12/21/2004
• Published: 11/10/2005
• Est. Priority Date: 01/30/2004
• Status: Active Grant

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Rollet, Romain, Mangin, Christophe
• Granted Patent: US 7,525,970 B2
• Time in Patent Office: Days
• US Class Current: 370/229
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/165 Combined use of TCP and UDP protocols; selection criteria therefor
• CPC Class Codes: H04W 28/22 Negotiating communication rate
• CPC Class Codes: H04W 72/56 based on priority criteria
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

There is disclosed a method of dynamic transmission resource allocation in a wireless network comprising a plurality of Mobile Terminals or MTs each managing a given number of different data flows (4-9) of Protocol Data Units or PDUs which are classified according to a set of flow types, a Radio Resource Management or RRM unit for allocating transmission resources on a per PDU basis; a plurality of schedulers (2,3) operating according to a specific set of rules; and a selector (1) for sharing the transmission resource among the MTs. The MTs or the RRM unit send Request Resource or RR messages to the RRM unit to request transmission resource. The RRM unit dispatches the RR messages to the schedulers based on flow type information included in each RR message. Each one of the schedulers elects one PDU as candidate for a next transmission resource allocation. The selector (1) allocates transmission resource to one candidate according to a set of priority rules, a given priority being assigned to each flow type. The specific set of rules comprises a rule applied in case of transmission errors for reducing the bandwidth allocated to data flows belonging to the flow types assigned with comparatively lower priority compared to the bandwidth allocated thereto according to a rule applied in case of error free transmission.

Claims

1. Method of dynamic transmission resource allocation in a wireless network comprising:

a plurality of Mobile Terminals or MTs each managing a given number of different data flows of Protocol Data Units or PDUs which are classified according to a set of predetermined flow types;

a Radio Resource Management or RRM unit for allocating transmission resources on a per PDU basis;

a plurality of schedulers, each being associated to a respective flow type and each carrying out a respective scheduling scheme according to a specific set of rules; and

a selector for sharing said transmission resource among said MTs, said method comprising;

said MTs or said RRM unit requesting transmission resource for transmission of pending PDUs by sending Request Resource or RR messages to said RRM unit each RR message including a flow type information;

said RRM unit dispatching said RR messages to said associated schedulers based on said flow type information;

each one of said associated schedulers electing one PDU of one data flow of said respective flow type as candidate for a next transmission resource allocation among said data flows of said respective flow type, independently from the other schedulers and based on said specific set of rules;

said selector allocating transmission resource to one candidate chosen among said candidates as a function of a set of priority rules where a respective priority is assigned to each flow type;

wherein the set of predetermined flow types comprises a first set of flow types assigned with comparatively higher priorities and a second set of flow types assigned with comparatively lower priorities;

wherein the set of rules specific to a scheduler associated to a flow type belonging to said second set of flow types comprises a first subset of rules applied in case of error free transmission, and a second subset of rules, different from said first subset of rules applied in case of transmission errors;

and wherein said second subset comprises a rule for reducing the bandwidth allocated to data flows belonging to said second set of flow types compared to the bandwidth allocated thereto according to said first subset of rules.

2. Method of claim 1, wherein the first set of flow types comprises real time data flows and the second set of flow types comprises non real time data flows.

3. Method of claim 1 or 2, wherein the set of priority rules applied by the selector comprises a rule which provides that transmission resource is allocated in a hierarchical manner as a function of the respective flow type priorities, an available transmission resource being granted first to the candidate of the flow type of the first set of flow types which exhibits the highest priority.

4. Method of any one of the preceding claims, wherein the set of priority rules further comprises a rule which provides that high priority is assigned to a flow type which is comparatively less tolerant to transmission delay and that low priority is assigned to a flow type which is comparatively more tolerant to transmission delay.

5. Method of claim 4, wherein the rule for reducing the bandwidth allocated is based on a pre-emption factor ρ

, which is administratively set for each data flow belonging to the second set of flow types.

6. Method of claim 4 or 5, wherein the specific set of rules corresponding to a flow type of the second set of flow types comprises a rule based on a Self Clocked Fair Queuing or SCFQ algorithm, and wherein the transmission resource allocation is based on a weight associated to each data flow in order to perform the election of candidate in a given proportion of a predetermined share of bandwidth.

7. Method of claim 6, wherein the second subset of rules further comprises a rule applied when transmission errors are detected on at least one data flow, according to which rule the election of candidate for the next transmission resource allocation is performed in priority among a set of data flows experiencing transmission errors and, among said set of data flows in proportion to the weight of each data flow.

8. Method of any one of the preceding claims, wherein the specific set of rules corresponding to a flow type of the first set of flow types comprises a rule based on a Virtual Scheduling Algorithm or VSA algorithm where the resource allocation is function of a Theoretical Transmission Time or TTT_i between emission of two consecutive packets in a given data flow of said flow type so as to provide delay and bandwidth guarantees.

9. Method of claim 8, wherein the specific set of rules corresponding to a flow type of the first set of flow types further comprises a rule applied when transmission errors are detected on a given data flow, said rule electing a candidate for the next transmission resource allocation while according to the following steps:

defining an age age(PDU) for all given PDUs to be retransmitted;

defining an age maximum A_max for each data flow;

allocating resource transmission to the data flow where;

age(PDU)/A_max, is equal to the greatest value;

discarding PDUs to be retransmitted when the corresponding age is greater than A_max.

10. Method of any one of the preceding claims, wherein the first set of flow types and the second set of flow types respectively comprises one flow type only.

11. Method of any one of the preceding claims, wherein the RR messages comprises an information as to the amount of requested transmission resource and wherein each scheduler and the selector take said information into account.

12. Method of any one of the preceding claims, wherein transmission errors detection is performed through an ARQ scheme via feedback messages.

13. Device for allocating transmission resource comprising means for carrying out a method of any one of the preceding claims.