Method for reducing transmission delays in a packet transmission system

• US 5,555,266 A
• Filed: 10/04/1993
• Issued: 09/10/1996
• Est. Priority Date: 10/04/1993
• Status: Expired due to Fees

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Doss, William K., Robbins, Karen E., Buchholz, Dale R., Hamilton, R. Lee Jr.
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): VU, HUY DUY
• Application Number:
  US08/131,358
• Time in Patent Office: 1,072 Days
• Field of Search: 370/95.1, 370/95.2, 370/95.3, 370/85.8, 370/85.7, 370/85.6, 370/58.1, 370/61, 370/79, 371/48, 371/57.1, 371/57.2, 371/65, 371/67.1, 455/33.1, 455/33.2, 455/33.4, 455/54.1, 455/67.1, 455/67.7, 455/68, 455/54.2, 455/56.2, 455/34.1, 455/34.2, 455/58.1, 360/825.08, 360/825.03, 360/825.15
• US Class Current: 370/347
• CPC Class Codes: H04L 1/1614 using bitmaps
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04W 28/14 using intermediate storage
• CPC Class Codes: H04W 72/044 based on the type of the allocated resource
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 74/004 in the uplink, i.e. towards network

Abstract

A packet transmission system (100) with reduced transmission delays includes a communications controller (110) and a plurality of remote requesting units (112) requesting packet transmission services. Each remote unit (112) sequentially stores transmitted access requests (302) in a memory queue (500) and awaits a resource grant (306) from the communications controller (110). Upon receipt of a granted resource the remote unit (112) will apply the granted resource to the oldest request (502) stored in the queue (500) in order to transmit data (310) to the communications controller (110). A separate and distinct aspect of the transmission system (100) resides within the communications controller (110). In response to the receipt of a data packet (310) from a remote unit (112), the communications controller (110) identifies missing data within the data packet transmission, determines whether communication resources are available to support retransmission of the missing data, and if so, transmits a response to the requesting remote unit identifying the missing data and simultaneously granting sufficient resources for retransmission of the missing data.

Claims

1. In a packet transmission system wherein a plurality of remote units request service from a communications controller by transmitting plural access requests to said communications controller, establishing a time within which a response to a given one of the access requests is anticipated and retransmitting said given access request upon expiration of the established time, a method for reducing transmission delays, said method comprising the steps of:

at the remote units;

storing the plural transmitted access requests sequentially in memory;

awaiting resource grants from the communications controller; and

applying a resource grant next received from the communications controller to the oldest of the plural access requests stored in memory in order to transmit data packets to the communications controller.

2. The method of claim 1 further comprising the steps of:

starting a retry timer for each transmitted access request; and

retransmitting the access request upon expiration of the associated retry timer.

3. The method of claim 1 further comprising the steps of:

separating the data packet transmitted to the communications controller into a plurality of data packet fragments.

4. In a packet transmission system wherein a plurality of remote units request service from a communications controller by transmitting access requests to said communications controller, establishing a time within which a response is anticipated and retransmitting said access requests upon expiration of the established time, a method for reducing transmission delays, said method comprising the steps of:

at the remote units;

storing the transmitted access requests sequentially in memory;

awaiting resource grants from the communications controller; and

applying resource grants received from the communications controller to the oldest access request stored in memory in order to transmit data packets to the communications controller, wherein the step of applying resource grants received from the communications controller further comprises the steps of;

determining whether the resource grant was intended for the oldest access request in memory;

applying the resource grant to the oldest access request in memory;

deleting the oldest access request from memory;

determining a next oldest access request; and

retransmitting a single access request to the communications controller requesting communication resources for all unacknowledged access requests in memory between the next oldest access request and the access request the resource grant was intended for.

5. In a packet transmission system wherein a plurality of remote units request service from a communications controller by transmitting access requests to said communications controller, establishing a time within which a response is anticipated and retransmitting said access requests upon expiration of the established time, a method for reducing transmission delays, said method comprising the steps of:

at the remote units;

storing the transmitted access requests sequentially in memory;

awaiting resource grants from the communications controller; and

applying resource grants received from the communications controller to the oldest access request stored in memory in order to transmit data packets to the communications controller, wherein the step of applying the granted resource further comprises the steps of;

determining whether the granted resource is sufficient to service the oldest access request; and

if so, transmitting a number of data packet fragments as specified by the oldest access request.

6. The method of claim 5 further comprising the steps of:

starting a timeout timer for each transmitted data packet fragment;

awaiting a response from the communications controller indicating receipt of data;

awaiting a response from the communications controller indicating a need to retransmit data;

upon receipt of a response indicating a need to retransmit data, refraining from transmitting a retransmit request to the communications controller requesting additional communications resources; and

transmitting a retransmit request to the communications controller requesting additional communications resources upon expiration of the associated timeout timer.

7. The method of claim 6 wherein the response from the communications controller indicating a need to retransmit data further comprises a resource grant from the controller for use by the remote unit during data retransmission.

8. The method of claim 5 further comprising the steps of:

determining whether resource grants are still available after the number of resource grants necessary to transmit the oldest access request are transmitted; and

applying said still available resource grants to a next oldest access request in memory.

9. In a packet transmission system wherein a plurality of remote units request service from a communications controller by transmitting access requests to said communications controller, establishing a time within which a response is anticipated and retransmitting said access requests upon expiration of the established time, a method for reducing transmission delays, said method comprising the steps of:

at the remote units;

storing the transmitted access requests sequentially in memory;

awaiting resource grants from the communications controller; and

applying resource grants received from the communications controller to the oldest access request stored in memory in order to transmit data packets to the communications controller, wherein the step of applying the granted resource further comprises the steps of;

determining whether the granted resource is sufficient to service the oldest access request; and

if not, transmitting a number of data packet fragments as specified in the grant.

10. The method of claim 9 further comprising the steps of:

starting a timeout timer for each transmitted data packet fragment;

awaiting a response from the communications controller indicating receipt of data;

awaiting a response from the communications controller indicating a need to retransmit data;

upon receipt of a response indicating a need to retransmit data, refraining from transmitting a retransmit request to the communications controller; and

transmitting a retransmit request to the communications controller requesting additional communication resources upon expiration of the associated timeout timer.

11. In a packet transmission system wherein a plurality of remote units request service from a communications controller by transmitting access requests to said communications controller, said communications controller receiving said access requests, storing the requests in a first memory queue, allocating and communicating resource grants to the plurality of remote units and awaiting data packet transmissions from the plurality of remote units, a method for reducing transmission delays when lost, corrupted or otherwise unintelligible data packet transmissions are received by the communications controller comprising the steps of:

at the communications controller, upon receipt of data packet transmissions from any one of said plurality of remote units;

identifying lost, corrupted or otherwise unintelligible data within the data packet transmissions from any one of said plurality of remote units;

determining whether communication resources are available to support retransmission of the lost, corrupted or otherwise unintelligible data; and

if so, transmitting a response to any one of said plurality of remote units exhibiting lost, corrupted or otherwise unintelligible data transmissions, said response identifying the lost, corrupted or otherwise unintelligible data data and simultaneously granting sufficient communications resources to any one of said plurality of remote units exhibiting lost, corrupted or otherwise unintelligible data transmissions for retransmission of the to lost, corrupted or otherwise unintelligible data.

12. The method of claim 11 further comprising the steps when communication resources are unavailable of:

transmitting a response to any one of said plurality of remote units exhibiting lost, corrupted or otherwise unintelligible data transmissions, said response identifying the missing data;

generating a retransmit request for the lost, corrupted or otherwise unintelligible data;

storing the retransmit request in a second memory queue; and

when communication resources are available, allocating said communication resources to service the retransmit requests stored in the second memory queue.

13. The method of claim 11 wherein the step of determining whether communication resources are available further comprises the step of:

scheduling available communication resources to service retransmit requests stored in the second memory queue prior to servicing the access requests stored in the first memory queue.

14. In a TDMA packet transmission system wherein a plurality of remote requesting units request communication resources from a communications controller within said system by transmitting access requests to said communications controller, a remote unit for reducing transmission delays when lost, corrupted or otherwise unintelligible data is received by the communications controller, said remote unit comprising:

a transmitter for transmitting access requests to the communications controller requesting communication resources to facilitate transmission of data packets to the communications controller;

memory, coupled to the transmitter, for sequentially storing the access requests;

a receiver for receiving a signal from the communications controller indicating allocation of a resource grant;

a remote unit controller, coupled to the receiver and the transmitter for applying the resource grant received from the communications controller to the oldest access request stored in memory in order to transmit a data packet to the communications controller;

upon said data packet transmission, said remote unit controller awaiting a response from the communications controller indicating a need to retransmit at least some of the data; and

upon receipt of said response, said remote unit controller inhibiting the transmitter from transmitting an access request to the communications controller requesting additional communication resources.

15. In a TDMA packet transmission system wherein a plurality of remote units request communication resources from a communications controller by transmitting access requests to said communications controller prior to transmitting data packets to the communications controller, said communications controller for reducing transmission delays when lost, corrupted or otherwise unintelligible data packet transmissions are received comprising:

means for identifying lost, corrupted or otherwise unintelligible data within said data packet transmissions;

means, coupled to the identifying means, for determining whether communication resources are available to support retransmission of the lost, corrupted or otherwise unintelligible data; and

means for transmitting a single response to the remote unit that identifies the lost, corrupted or otherwise unintelligible data and grants communication resources to the remote unit for retransmission of the lost, corrupted or otherwise unintelligible data.

16. The system of claim 15 wherein communication resources comprise frequency spectrum and TDMA time slots.

17. In a TDMA packet transmission system wherein a plurality of remote units request communication resources from a controller by transmitting multiple requests to said controller, a method for reducing transmission delays within said system comprising the steps of:

the remote unit;

transmitting access requests to the controller requesting resources to facilitate transmission of data packets to the communications;

storing the requests sequentially in memory;

awaiting a resource grant from the controller;

applying the resource grant received from the controller to the oldest access request stored in memory in order to transmit a data packet to the controller;

awaiting a response from the controller indicating a need to retransmit at least some of the data; and

upon receipt of said response, refraining from transmitting a retransmit request to the controller requesting additional communication resources;

at the controller;

receiving the transmitted data packet;

identifying missing data from within the data packet transmission;

determining whether communication resources are available to support retransmission of the missing data; and

if so, transmitting a single response to the requesting device identifying the missing data and simultaneously granting sufficient resources for retransmission of the missing data.