WO2012087110A1

WO2012087110A1 - A system and method for reducing end-to-end data retransmission

Info

Publication number: WO2012087110A1
Application number: PCT/MY2011/000241
Authority: WO
Inventors: Nordin Ramli; David CHIENG HENG TZE; Zeldi Suryady; Mohamad MOHD ARIFF
Original assignee: Mimos Berhad
Priority date: 2010-12-22
Filing date: 2011-12-20
Publication date: 2012-06-28
Also published as: MY182187A

Abstract

The present invention discloses a system for reducing end to end retransmission in a network, whereby the system comprises, at least one base station (100) comprising a peer group coordinator module (PGC); at least one peer group (300) comprising at least two members; at least one means for storing said peer group members' data segments (200); and at least one means for retrieving said data segments, communicating with the peer group coordinator (PGC) and other devices within the network. In one embodiment of the present invention, data loss during a disrupted link or connectivity is retrieved via two different modes, these are the device coordinated mode and peer group coordinated mode.

Description

A SYSTEM AND METHOD FOR REDUCING END-TO-END DATA

RETRANSMISSION

FIELD OF INVENTION

The present invention relates generally to wireless connectivity systems, and more particularly to a system and method for reducing the occurrence of data re-transmission due to link disruption in a wireless network.

BACKGROUND OF INVENTION

Wireless network technology enables users to exchange data by means of wireless nodes thus allowing mobility for users. The recent technological advancement in wireless communications, have led to the development of various wireless networking protocols .

The general challenges nowadays in wireless networking arise primarily due to the large number of constraints in relation to connectivity breakdown or instability due to interferences and disruptions, as well as device mobility. As a result to such disruptions in data transmission within a network, frequent data transmissions has become a necessity at various protocol layers so as to ensure data integrity. One of the most important constraints associated to retransmission of data is that in many cases the breakdown of connectivity exceeds a predetermined period the lost data cannot be recovered by per hop retransmission techniques between the base station and the wireless terminal as those demonstrated by Medium Access Control (MAC) layer. Accordingly at this stage, the end-to-end retransmission across multiple hops or even multiple networks for example using the Transmission Control Protocol (TCP) is inevitable. It will not only increase network delay but also leads to resource wastage and network congestion. US 2009/0034488 disclosed a base station apparatus and data retransmission method thereof. This method aids to improve the reliability of retransmission by means of increasing transmitting power and by modulation method which can provide higher error resistance. Nevertheless, it is concluded that this prior art document does not disclose any specific details on using ad-hoc peer-group for the first level of retrieval, or associating each mobile station with its neighbor mobile station. Further, this document teaches a system which is performed or employed only at the base station. From the above, it would be highly desirable to provide a method and system for reducing the occurrences of retransmission, preferably enabling retrieval, request and transfer of data segments devoid of interruption on the existing operation.

Therefore the object of the present invention is to provide a system and method for minimizing or reducing end to end data retransmission using Peer Group (PG) approach.

It is yet an object of the present invention to provide a method and system for reducing data retransmission, wherein the devices are configured to request directly from PG members .

It is another object of the present invention to provide a method and system for reducing data retransmission whereby the present invention intends to improve data retransmission, reduce delay and decrease network congestion.

It is yet another object of the present invention to provide a method and system for reducing data retransmission, whereby there are two approaches for retrieval of data, first is based on device coordinated and second is based on peer group coordinated . It is a further object of the present invention to provide a method and system for reducing data retransmission, whereby the retrieval of data either from Peer Group Coordinator (PGC) or devices directly must be fast or completed before the retransmission takes place within the system.

Other objects of this invention will become apparent on the reading of this entire disclosure.

SUMMARY OF INVENTION

In one aspect there is disclosed a system for reducing end to end retransmission in a network comprising: at least one base station (100) comprising a peer group coordinator module

(PGC); at least one peer group (300) comprising at least two members (200) ; at least one means for storing said peer group members' data segments; at least one means for retrieving said data segments, communicating with the peer group coordinator

(PGC) and other devices within the network.

In another aspect there is provided A method for reducing end to end transmission of wireless communication within the network comprising the steps of: providing at least one peer group having at least two members; storing data segments; retrieving lost data directly from peer group members; retrieving lost data via a peer group coordinator (PGC) ; and waiting for end to end retransmission to retrieve lost data.

BRIEF DESCRIPTION OF DRAWINGS

Other objects, features, and advantages of the invention will be apparent from the following description when read with reference to the accompanying drawings. In the drawings, wherein like reference numerals denote corresponding parts throughout the several views: FIG 1 shows the overall system in accordance with a preferred embodiment of the present invention;

FIG 2 shows the wireless device used in accordance with the preferred embodiment of the present invention;

FIG 3 shows the overall flowchart in accordance with the preferred embodiment of the present invention;

FIG 4 shows the PG members listing in accordance with the preferred embodiment of the present invention; FIG 5 shows the formation and maintenance of PG in device coordinated mode in accordance with a preferred embodiment of the present invention;

FIG 6 shows the data retrieval process in accordance with the preferred embodiment of the present invention;

FIG 7 (a) and 7 (b) show the data request and response message format in accordance with a preferred embodiment of the present invention;

FIG 8 shows the Layer 3 retransmission timeout (RTO) ;

FIG 9 shows the steps involved for data storage at each participating device in accordance with a preferred embodiment of the present invention;

FIG 10 shows the steps involved for data retrieval in accordance with a preferred embodiment of the present invention;

FIG 11 shows the message sequence chart for reducing end to end retransmission in accordance with a preferred embodiment of the present invention. DETAILED DESCRIPTION

In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known methods, procedures and/or components have not been described in detail so as not to obscure the invention. Reference will now be made in detail to the preferred embodiments of the present invention,- examples of which are illustrated in the accompanying drawings.

The present invention is a method and system for reducing end to end retransmission of data between connected nodes or devices within a wireless network, particularly when disruption of connectivity occurs.

Referring to FIG 1, the system of the present invention comprises a base station (100), at least one wireless device (200), and peer groups (PGs) (300).

The base station (100) in accordance with a preferred embodiment of the present invention is configured to provide radio access to the participating wireless devices (200) . A peer group (PG) coordinator module is deployed within the base station (100) in order to manage the peer groups (PGs) members and information related to the members. The wireless devices (200) , as shown in FIG 2 are preferably portable devices and are connected to the base station (100) . Each of the wireless devices (200) is provided with a Temporary Data Segment Storage (TDSS) and a Temporary Data Segment Storage Agent (TDSSA) . For this invention, the TDSSA is configured to perform the tasks of data segment storage and retrieval, communicating with local TCP agent, and communicating with PGC as well as peer TDSSAs.

The peer groups (PGs) in accordance with the preferred embodiment of the present invention comprises of neighboring devices, at least two member devices, designated to provide temporary storage space for the data transmitted, or received by other members. The peer group members (300) are configured to communicate with each other directly or via an intermediate device such as the PGC. The present invention enables the peer group members (300) to retrieve loss data segments without the need to wait for end to end retransmission from the sending host . Further in accordance with the preferred embodiment of the present invention, each participating wireless device (200) is configured to allocate temporary data segment storage (TDSS) space to aid in storing data segments within the PG members. This feature plays a major role in enabling data retrieval between the members of the PG in the event that a link disruption occurs. Each data segment preferably has a form of identification so as to distinguish the owners of data segments or to determine which device the data segment belongs to. Such identification may also provide a form of indexing function, for example, a sequence number in order to indicate the sequence of the data segment. In addition, different buffers are allocated for different PG members.

The general operation of the method and system of the present invention in accordance with a preferred embodiment will be described herein with reference to FIG 3.

The neighbors for the PG for present invention is selected based on the received power signal, such as, but not limiting to, receiver signal strength (RSS) , radio signal strength (RSSI), signal to noise ratio (SNR) , signal to interference ratio (SIR) and signal to interference plus noise ratio (SINR) .

As mentioned, during operation, each participating device (200) is configured to allocate temporary data segment storage in order to store data segments of the PG members. The size of storage is predetermined, and dependant on the capacity or willingness of each device. All data segments are provided with a form of identification and numbering. FIG 4 shows the PG members listing in TDSS.

FIG 3 shows the overall flow of the method in accordance with the preferred embodiment, whereby there are involved the steps of formation and maintenance of peer groups (PG) for both devices coordinated and PGC coordinated mode, putting the system on standby to detect data loss and initiating data retrieval in the event that data loss is detected. Further elaboration on the steps will be provided herein.

In accordance with the preferred embodiment of the present invention, upon formation of PGs to store data segments of members in TDSS, the TDSSA proceeds to initialize PG to retrieve lost data by requesting directly from PG members which is device coordinated. If this fails, TDSSA will initiate PG to retrieve lost data by requesting directly from PG members outside the current PG via PGC. If the latter approach fails, the TDSSA will therefore wait for end to end transmission to retrieve lost data from sender.

With respect to the step of formation and maintenance for device coordinated and PGC coordinated mode shown in FIG 3 being the overall operation flow, the steps for such formation and maintenance are depicted in FIG 5. The first step is broadcasting PG invitation to the neighboring devices by an originating device. Neighboring TDSSAs will reply the originating TDSSA and add the information of the responded devices as new PG member in local database. The TDSSA is configured to constantly check the PG member' s device radio signal quality, to determine whether it is below or above the predetermined threshold. Further, the TDSSA will accordingly update the members list by removing PG member if the radio signal is below the required threshold.

FIG 6 shows the steps involved for data retrieval process as initially shown in FIG 3 being the overall chart. In accordance with the preferred embodiment of the present invention, there are two levels of data retrieval which are configured to take place of one after another.

The first level is the device coordinated approach, whereby the device requests directly from its PG members, while the second level is the PGC coordinated, in which the device requests from PG members via PGC. Now referring to FIG 6, data is assumed lost in the event that the respective data segment does not arrive after link level re-try period expires. The receiver is assumed to know the retry expiry time at priori. If damaged data segment is detected, the original device therefore proceeds to initiate device coordinated data retrieval. During this retrieval, TDSSA of originating device broadcasts data request message to PG members. The PG members that store the requested data segment will accordingly respond to the broadcasted request, as shown in FIG 7 (a) and 7 (b) . Subsequently, the TDSSA proceeds to retrieve data from the responded member.

Alternatively, in the event that there is no response from the local members, TDSSA will proceed to initiate the PGC coordinated approach. In this retrieval, TDSSA will request PGC to broadcast data request message to devices outside the current PG. Any member outside the current PG which stores the data segment will respond to said request and thus the TDSSA proceeds to retrieve data from said member.

If both approaches fail, the participating devices will therefore resort to wait for end to end data retransmission from the sender to take place or reinitialize the transmission. Nevertheless, both approaches as described above are expected to take place fast enough prior to the retransmission or before the retransmission time out (RTO) , as seen in FIG 8. TCP will start a retransmission timer when each outbound segment is handed down to IP. In the event that no acknowledgement was received for the data given segment before the timer expires, then the segment is configured to be retransmitted. Typical values used for this parameter is around 3-5 seconds for high speed networks and may be much higher for slower links.

FIG 9 shows the steps involved for data storage at each participating device. Each device will receive data buffers from BS, which may belong to itself or others. Upon receipt of data, TDSSA proceeds to check the identity of data segment to determine whether said data segment belongs to itself or other members of the PG. If the data segment belongs to itself, TDSSA will store the data to main buffer otherwise, the TDSSA will store data to TDSS if it belongs to other members. In the event that the data segment does not belong to any of the members or itself, it will discard the data.

FIG 10 shows the shows the steps involved for data retrieval. Upon receipt data segment request, the device will check the requester's identity if it is from the PG members or not. In the event that the requester is from PG members, TDSSA will check requested data segment index either data segment available or not in its own TDSS. TDSSA then proceeds to send positive response to requester if requested data segment available and wait for requester to response by requesting for connection to transfer requested data segments. Once the requester request accepted, TDSSA will transfer the requested data segments to requester.

FIG 11 shows the message sequence chart for reducing the end to end retransmission in accordance with a preferred embodiment of the present invention. As elucidated in the preceding paragraphs, the message sequence is subjected to the identification of the data segments, as to the determination of the data segment requestor and to which member the data segment belongs to.

As will be readily apparent to those skilled m the art, the present invention may easily be produced in other specific forms without departing from its essential characteristics. The present embodiments is, therefore, to be considered as merely illustrative and not restrictive, the scope of the invention being indicated by the claims rather than the foregoing description, and all changes which come within therefore intended to be embraced therein.

Claims

1. A system for reducing end to end retransmission in a network comprising:

At least one base station (100) comprising a peer group coordinator module (PGC) ;

At least one peer group (300) comprising at least two members;

At least one means (200) for storing said peer group members' data segments;

At least one means for retrieving said data segments, communicating with the peer group coordinator (PGC) and other devices within the network.

2. The system as claimed in Claim 1 wherein the base station (100) further functions to manage and update information related to the peer group members based on radio signal quality.

3. The system as claimed in Claim 1 wherein the peer group members are formed based on neighboring devices configured to have temporary data segment storage (TDSS) on behalf of other members.

4. The system as claimed in Claim 1 wherein the peer group members further comprising members which can communicate with one another or via the peer group coordinator (PGC) .

5. The system as claimed in Claim 1 wherein the means for storing peer group member' s data is a temporary data segment storage means (TDSS) provided in wireless devices (200) .

6. The system as claimed in Claim 1 wherein the means for retrieving said data segments, communicating with the peer group coordinator (PGC) and other devices within the network is a temporary data segment storage agent (TDSSA) .

The system as claimed in Claim 1 wherein the means for storing said peer group members' data segments stores the peer group members' data segments which resides in wireless devices (200), and further comprises identifications for each peer group member of which the data segment belongs to.

The system as claimed in Claim 1 wherein the means for retrieving said data segments, communicating with the peer group coordinator (PGC) and other devices within the network further updates participating devices as peer group members in a local database and sort them based on radio signal quality .

9. A method for reducing end to end retransmission of wireless communication within the network comprising the steps of:

Providing at least one peer group having at least two members;

Storing data segments;

Retrieving lost data directly from peer group members;

Retrieving lost data via a peer group coordinator (PGC); and

Waiting for end to end retransmission to retrieve lost data.

0. The method as claimed in Claim 9 further comprising the steps of formation and maintenance of peer group through device coordinated mode.

1. The method as claimed in Claim 10 wherein the step of formation and maintenance of peer group device coordinated mode comprises the steps of:

Broadcasting peer group invitation to neighboring data segment storage agents; Replying to the said broadcasted invitation and maintaining the information as peer group members in a local database; Checking peer group member' s device radio signal quality; and

Updating peer group member' s lost by removing a peer group member with radio quality below a threshold.

2. The method as claimed in Claim 9 further comprising the steps of formation and maintenance of peer group through a peer group coordinator.

3. The method as claimed in Claim 12 further comprising the steps of :

Periodically broadcasting peer group invitation to all data segment storage agents with cell coverage; Replying to said invitation and providing radio quality information;

Accepting replies and maintaining information as peer group members in a local database;

Periodically checking peer group member' s radio signal quality;

Updating the peer . group member' s list by removing peer group members if their radio quality is below than threshold.

14. The method as claimed in Claim 9 further comprising the step of retrieving data segment at devices.

15. The method as claimed in Claim 14 wherein the step of retrieving data segment comprises the steps of broadcasting data segment request message to peer group members; retrieving data segments from responded members; requesting peer group coordinator to broadcast data segment request message to devices outside the current peer group; and retrieving data segments from the responded member outside of peer group .

16. The method as claimed in Claim 9 wherein the step of storing data segments further comprises the steps of receiving data segments from base station (100); checking the identity of data segment; storing data segments to main buffer or to a temporary data segment storage (TDSS) ; and ignoring data segment belonging to other members which are not peer group members.

17. The method as claimed in Claim 14 wherein the step of retrieving data segment at devices further comprises the steps of broadcasting data segment request to other peer group members and checking responding peer group member' s identity whether it is from a peer group member.