System and method for providing quality of service and contention resolution in ad-hoc communication systems

• US 6,928,085 B2
• Filed: 03/12/2001
• Issued: 08/09/2005
• Est. Priority Date: 03/12/2001
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Haartsen, Jacobus
• Primary Examiner(s): HO, DUC CHI
• Application Number:
  US09/804,288
• Publication Number:
  US 20020126692A1
• Time in Patent Office: 1,611 Days
• Field of Search: 370/294, 370/230, 370/236, 370/336, 370/346, 370/455, 370/447, 370/458, 370/431, 370/461, 370/462, 370/466, 370/467, 370/347, 455/509, 455/450, 709/236, 709/226, 709/229, 709/208, 709/104
• US Class Current: 370/462
• CPC Class Codes: H04W 28/24 Negotiating SLA [Service Level Agreement]; Negotiating QoS [Quality of Service]
• CPC Class Codes: H04W 28/26 Resource reservation
• CPC Class Codes: H04W 72/56 based on priority criteria
• CPC Class Codes: H04W 74/04 Scheduled access hybrid access H04W74/02
• CPC Class Codes: H04W 80/00 Wireless network protocols or protocol adaptations to wireless operation
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

Systems and methods for providing access to a time-slotted communication channel are disclosed. Access to the channel is granted by possession of a pseudo-token transmitted between communication units with packets, such that the recipient of a data packet receives the pseudo-token with the packet. Communication units may be assigned reserved slots during which the pseudo-token automatically is assigned to the communication unit. Further, communication units may be assigned priority levels according to which contention contests may be resolved. Reserved slots and priority rankings may used in combination to accommodate varying levels of QoS required or requested by communication units on the channel.

Claims

1. A method of allocating to communication units transmit time slots in a communication channel that implements a pseudo-token, ping-pong channel access protocol wherein a receiving unit obtains the right to transmit on the channel with the receipt of a data packet, comprising the steps of:

allocating reserved time slots to communication units based on QoS requirements associated with the communication units, wherein the pseudo-token is automatically assigned to a communication unit during its reserved time slot;

assigning priority levels to communication units transmitting on the communication channel; and

interrupting the pseudo-token based channel access scheme when a communication unit'"'"'s reserved time slot is overridden by a transmission from a higher priority communication unit.

2. A method according to claim 1, wherein the step of allocating reserved time slots to communication units further comprises the step of:

receiving, at a master unit, an access request from a slave unit, wherein the access request includes QoS parameters requested by the slave unit.

3. A method according to claim 1, wherein the step of allocating reserved time slots to communication units further comprises the step of:

allocating a maximum packet size to communication units based on QoS requests from the communication units.

4. A method according to claim 1, wherein the step of allocating reserved time slots to communication units further comprises the step of:

assigning time offsets between the reserved time slots allocated to communication units.

5. A method according to claim 1, wherein the priority level assigned to a communication unit is based on the QoS requested by the communication units.

6. A method according to claim 1, wherein the step of interrupting the pseudo-token based channel access scheme comprises passing the virtual token to the communication unit which had its transmission time slot overridden.

7. A method according to claim 1, wherein a communication unit forfeits its right to transmit on the communication channel when its reserved time slot is overridden by a transmission from a higher priority communication unit.

8. A communication system, comprising:

a plurality of communication units, the communication units having a transmitter for transmitting data packets on a time slotted communication channel and a receiver for receiving data packets on the time slotted communication channel, wherein one of the communications units acts as a master communication unit for implementing a pseudo-token, ping-pong channel access protocol wherein a receiving unit obtains the right to transmit on the channel with the receipt of a data packet;

the master communication unit including;

a module for allocating reserved time slots to at least one of the communication units based on QoS requirements associated with the communication units, wherein the pseudo-token is automatically assigned to a communication unit during its reserved time slot;

a module for assigning priority levels to communication units transmitting on the communication channel; and

a module for interrupting the token-based channel access scheme when a communication unit'"'"'s transmission time slot is overridden by a transmission from a higher priority communication unit.

9. A communication system according to claim 8, wherein the master communication unit assigns reserved time slots based on QoS parameters requested by a slave communication unit.

10. A communication system according to claim 8, wherein the master communication unit assigns a maximum packet size to slave communication units based on QoS requests from the slave communication units.

11. A communication system according to claim 8, wherein the master communication unit assigns time offsets between the reserved time slots allocated to communication units.

12. A communication system according to claim 8, wherein the master communication unit assigns priority levels to slave communication units based on the QoS requested by the slave communication units.

13. A communication system according to claim 8, wherein the master unit interrupts the virtual token-based channel access scheme when a communication unit'"'"'s transmission time slot is overridden by a transmission from a higher priority communication unit.

14. A communication system according to claim 13, wherein the master unit passes the virtual token to the communication unit which had its transmission time slot overridden.

15. A communication system according to claim 8, wherein a communication unit forfeits its right to transmit on the communication channel when its reserved time slot is overridden by a transmission from a higher priority communication unit.

16. A communication device for communicating over a communication channel that implements a pseudo-token based access scheme wherein a receiving communication device obtains the right to transmit on the channel with the receipt of a data packet, comprising:

a transmitter for transmitting data packets directly to other communication devices on a time-slotted communication channel;

a receiver for receiving data packets directly from other communication devices on the time-slotted communication channel; and

a controller for controlling access to the time-slotted communication channel during a communication session with another communication device wherein the controller includes;

a transmission time slot allocation module for allocating reserved time slots to at least one communication device based on QoS requirements associated with the communication devices, wherein the pseudo-token is automatically assigned to a communication unit during its reserved time slot;

a priority assignment module for assigning priority levels to communication devices transmitting on the communication channel; and

a token assignment module for interrupting the token-based channel access scheme when a communication device'"'"'s transmission time slot is overridden by a transmission from a higher priority communication device.

17. A communication device according to claim 16, wherein the transmission time slot allocation module allocates reserved time slots based on QoS parameters requested by a slave communication unit.

18. A communication device according to claim 16, wherein the controller assigns a maximum packet size to communication devices based on QoS requests from the communication devices.

19. A communication device according to claim 16, wherein the transmission time slot allocation module assigns time offsets between the reserved time slots allocated to communication devices.

20. A communication device according to claim 16, wherein the priority assignment module assigns priority levels to communication devices based on the QoS requested by the communication devices.

21. A communication device according to claim 16, wherein the token assignment module interrupts the pseudo-token based channel access scheme when a communication device'"'"'s assigned transmission time slot is overridden by a transmission from a higher priority communication unit.

22. A communication device according to claim 21, wherein the token assignment module passes the pseudo-token to the communication unit which had its transmission time slot overridden.

23. A communication device according to claim 21, wherein the token assignment module forfeits a communication unit'"'"'s right to transmit on the communication channel when its reserved time slot is overridden by a transmission from a higher priority communication unit.

24. A computer program product for controlling communications over a communication channel that implements a pseudo-token based access scheme wherein a receiving communication device obtains the right to transmit on the channel with the receipt of a data packet, comprising:

computer-readable storage medium having computer-readable program code means embodied in said medium, said computer-readable program code means including;

computer-readable program code means for allocating reserved time slots to at least one communication device based on QoS requirements associated with the communication devices, wherein the pseudo-token is automatically assigned to a communication unit during its reserved time slot;

computer-readable program code means for assigning priority levels to communication devices transmitting on the communication channel; and

computer-readable program code means for interrupting the token-based channel access scheme when a communication device'"'"'s transmission time slot is overridden by a transmission from a higher priority communication device.

25. A computer program product according to claim 24, wherein the transmission time slot allocation module allocates reserved time slots based on QoS parameters requested by a slave communication unit.

26. A computer program product according to claim 24, wherein the controller assigns a maximum packet size to communication devices based on QoS requests from the communication devices.

27. A computer program product according to claim 24, wherein the transmission time slot allocation module assigns time offsets between the reserved time slots allocated to communication devices.

28. A computer program product according to claim 24, wherein the priority assignment module assigns priority levels to communication devices based on the QoS requested by the communication devices.

29. A computer program product according to claim 24, wherein the token assignment module interrupts the pseudo-token based channel access scheme when a communication device'"'"'s assigned transmission time slot is overridden by a transmission from a higher priority communication unit.

30. A computer program product according to claim 29, wherein the token assignment module passes the pseudo-token to the communication unit which had its transmission time slot overridden.

31. A computer program product according to claim 30, wherein the token assignment module forfeits a communication unit'"'"'s right to transmit on the communication channel when its reserved time slot is overridden by a transmission from a higher priority communication unit.