Rate allocation and control for multicast services in wireless networks

• US 20030156540A1
• Filed: 02/20/2002
• Published: 08/21/2003
• Est. Priority Date: 02/20/2002
• Status: Active Grant

• Current Assignee: RPX Corporation
• Original Assignee: Nokia Corporation
• Inventors: Trossen, Dirk, Chaskar, Hemant M.
• Granted Patent: US 6,996,104 B2
• Time in Patent Office: Days
• US Class Current: 370/232
• CPC Class Codes: H04L 12/1836 with heterogeneous network architecture
• CPC Class Codes: H04L 12/185 with management of multicast group membership
• CPC Class Codes: H04L 12/1877 Measures taken prior to transmission
• CPC Class Codes: H04L 12/189 in combination with wireless systems selective distribution or broadcast in wireless communication networks H04W4/06
• CPC Class Codes: H04L 61/00 Network arrangements, protocols or services for addressing or naming
• CPC Class Codes: H04W 28/22 Negotiating communication rate
• CPC Class Codes: H04W 40/02 Communication route or path selection, e.g. power-based or shortest path routing
• CPC Class Codes: H04W 72/30 Resource management for broadcast services
• CPC Class Codes: H04W 76/11 Allocation or use of connection identifiers

Abstract

The present invention provides methods and apparatus for transmitting of multicast data over a wireless channel. At least one wireless terminal requests a multicast service corresponding to at least one requested layer. A wireless infrastructure comprising a base station and a node determines a data rate that the at least one wireless terminal can reliably receive and correspondingly configures a multicast session for at least one layer. The node utilizes measurements provided by the wireless terminal. The node through the base station signals the wireless terminal about a link-level multicast address corresponding to a time slot for which the wireless terminal shall process packets.

Claims

1. Apparatus for allocating and controlling a transmission rate for a multicast session in a wireless communications system, the multicast session providing a multicast service for a first wireless terminal over a wireless channel, the apparatus comprising:

at least one input/output (I/O) port;

a processor connected to the at least one I/O port in order to communicate with the first wireless terminal, the processor configured to perform the steps of;

(a) receiving a request that the first wireless terminal wishes to join to a multicast group;

(b) determining an allowable transmission rate for the first wireless terminal on a basis of signal quality information received from the first wireless terminal;

(c) assigning a layer to the first wireless terminal in response to step (a) and step (b), wherein the layer is associated with a multicast content;

(d) signaling a multicast address to the first wireless terminal in response to step (c); and

(e) scheduling packets for the layer.

2. The apparatus of claim 1, wherein step (e) utilizes a time slot.

3. The apparatus of claim 1, wherein the processor is configured to perform the further step of:

(f) repeating steps (b), (c), and (d) based upon updates of the allowable transmission rate for the first wireless terminal.

4. The apparatus of claim 3, wherein the updates result from a change in a factor selected from the group consisting of a signal quality, an occurrence of joining the multicast service, and occurrence of leaving the multicast service, and an available fraction of a link capacity.

5. The apparatus of claim 1, wherein step (b) comprises the steps of:

(i) obtaining a signal to noise ratio measurement corresponding to a received signal at the first wireless terminal on the wireless channel; and

(ii) converting the signal to noise ratio measurement to the allowable transmission rate.

6. The apparatus of claim 1, wherein step (b) comprises the steps of:

(i) obtaining at least one signal to noise (SNR) measurement corresponding to a received signal at the first wireless terminal on the wireless channel;

(ii) determining a SNR prediction from the at least one SNR measurement; and

(iii) converting the SNR prediction to the allowable transmission rate.

7. The apparatus of claim 6, wherein step (ii) comprises the step of averaging a plurality of SNR measurements.

8. The apparatus of claim 6, wherein the processor is configured to perform the further step of:

receiving the SNR prediction over the wireless channel in response to step (ii).

9. The apparatus of claim 6, wherein step (ii) comprises the step of detecting a movement of the wireless terminal.

10. The apparatus of claim 1, wherein step (c) comprises the steps of:

(i) ordering a sequence of a plurality of wireless terminals in accordance with allowable transmission rates, each of the allowable transmission rates corresponding to each of the plurality of wireless terminals, wherein the plurality of wireless terminals includes the first wireless terminal;

(ii) determining a number of layers that the first wireless terminal is able to receive reliably in accordance with a target error rate and an allowable throughput; and

(iii) assigning a time slot to the first wireless terminal at a data rate corresponding to the allowable throughput in response to step (ii).

11. The apparatus of claim 1, wherein the processor is configured to perform the further step of:

(f) receiving an update request that the first wireless terminal wishes to modify a subscription to the multicast group.

12. The apparatus of claim 7, wherein step (ii) comprises the steps of:

(1) multiplying a previous SNR prediction by a parameter;

(2) subtracting the parameter from a value equal to 1;

(3) multiplying a result from step (2) by a current SNR measurement; and

(4) adding a result in step (3) to a result in step (1).

13. The apparatus of claim 1, wherein step (b) comprises the steps of:

(i) obtaining a signal to noise ratio (SNR) measurement corresponding to a received signal at the first wireless terminal on the wireless channel;

(ii) determining a quality of service (QoS) level that is associated with the first wireless terminal; and

(iii) converting the SNR measurement and the QoS level to the allowable transmission rate.

32. The computer-readable medium of claim 31, wherein step (e) utilizes a time slot.

14. A method for allocating and controlling a transmission rate for a multicast session in a wireless communications system, the multicast session providing a multicast service for a first wireless terminal, the method comprising the steps of:

(a) receiving a request that the first wireless terminal wishes to join to a multicast group;

(b) determining an allowable transmission rate for the first wireless terminal on a basis of signal quality information received from the first wireless terminal;

(c) assigning a layer to the first wireless terminal in response to step (a) and step (b), wherein the layer is associated with a multicast content;

(d) signaling a multicast address to the first wireless terminal in response to step (c); and

(e) scheduling packets for the layer.

15. The method of claim 14, wherein step (e) utilizes a time slot.

16. The method of claim 14, comprising the further step of:

(f) repeating steps (b), (c), and (d) based upon updates of the allowable transmission rate for the first wireless terminal.

17. The method of claim 16, wherein the updates result from a change in a factor selected from the group consisting of a signal quality, an occurrence of joining the multicast service, and occurrence of leaving the multicast service, and an available fraction of a link capacity

18. The method of claim 14, wherein step (b) comprises the steps of:

(i) obtaining a signal to noise ratio measurement corresponding to a received signal at the first wireless terminal on the wireless channel; and

(ii) converting the signal to noise ratio measurement to the allowable transmission rate.

19. The method of claim 14, wherein step (b) comprises the steps of:

(i) obtaining at least one signal to noise (SNR) measurement corresponding to a received signal at the first wireless terminal on the wireless channel;

(ii) determining a SNR prediction from the at least one SNR measurement; and

(iii) converting the SNR prediction to the allowable transmission rate.

20. The method of claim 19, wherein step (ii) comprises the step of averaging a plurality of SNR measurements.

21. The method of claim 19, further comprising the step of:

receiving the SNR prediction over the wireless channel in response to step (ii).

22. The method of claim 19, wherein step (ii) comprises the step of detecting a movement of the first wireless terminal.

23. The method of claim 14, wherein step (c) comprises the steps of:

(i) ordering a sequence of a plurality of wireless terminals in accordance with allowable transmission rates, each of the allowable transmission rates corresponding to each of the plurality of wireless terminals, wherein the plurality of wireless terminals includes the first wireless terminal;

(ii) determining a number of layers that the first wireless terminal is able to receive reliably in accordance with a target error rate and an allowable throughput; and

(iii) assigning a time slot to the first wireless terminal at a data rate corresponding to the allowable throughput in response to step(ii).

24. The method of claim 14, wherein the multicast address is associated with a group of wireless terminals and wherein each member of the group is instructed to receive a transmission addressed to the multicast address.

25. The method of claim 24, wherein the multicast address is transmitted to the group of wireless terminals utilizing out-of-band signaling.

26. The method of claim 24, wherein the link-level multicast address is transmitted to the group of wireless terminals utilizing in-band signaling.

27. The method of claim 14, further comprising the step of:

(f) receiving an update request that the first wireless terminal wishes to modify a subscription to the multicast group.

28. The method of claim 20, wherein step (ii) comprises the steps of:

(1) multiplying a previous SNR prediction by a parameter;

(2) subtracting the parameter from a value equal to 1;

(3) multiplying a result from step (2) by a current SNR measurement; and

(4) adding a result in step (3) to a result in step (1).

29. The method of claim 14, wherein step (b) comprises the steps of:

(i) obtaining a signal to noise ratio (SNR) measurement corresponding to a received signal at the first wireless terminal on the wireless channel;

(ii) determining a quality of service (QoS) level that is associated with the first wireless terminal; and

(iii) converting the SNR measurement and the QoS level to the allowable transmission rate.

30. The method of claim 29, wherein the QoS level is associated with the group consisting of a packet error rate (PER), a bit error rate (BER), a maximum data rate, a time delay of packets, and a variation of the time delay of the packets.

31. A computer-readable medium containing instructions for allocating and controlling a computer system to provide transmission of multicast data over a wireless channel to a first wireless terminal in a wireless communications system, comprising instructions that perform the steps of:

(a) receiving a request that the first wireless terminal wishes to join to a multicast group;

(b) determining an allowable transmission rate for the first wireless terminal in response to receiving the request;

(c) assigning a layer to the first wireless terminal in response to determining the allowable transmission rate, wherein the layer is associated with a multicast content;

(d) signaling a multicast address to the first wireless terminal in response to assigning the layer; and

(e) scheduling packets for the layer.

33. The computer-readable medium of claim 31, wherein the processor is configured to perform the further step of:

(f) repeating steps (b), (c), and (d) based upon updates of the allowable transmission rate for the first wireless terminal.

34. The computer-readable medium of claim 33, wherein the updates result from a change in a factor selected from the group consisting of a signal quality, an occurrence of joining the multicast service, and occurrence of leaving the multicast service, and an available fraction of a link capacity.

35. The computer-readable medium of claim 31, further comprising instructions that perform the steps of:

obtaining a signal to noise ratio measurement corresponding to a received signal at the first wireless terminal on the wireless channel; and

converting the signal to noise ratio measurement to the allowable transmission rate.

36. The computer-readable medium of claim 31, further comprising instructions that perform the steps of:

obtaining at least one signal to noise ratio (SNR) measurement corresponding to a received signal at the first wireless terminal on the wireless channel;

determining a SNR prediction from the at least one SNR measurement; and

converting the SNR prediction to the allowable transmission rate.

37. The computer-readable medium of claim 31, further comprising instructions that perform the steps of:

ordering a sequence of a plurality of wireless terminals in accordance with allowable transmission values, wherein the plurality of wireless terminals includes the first wireless terminal;

determining a number of layers that the first wireless terminal is able to receive in accordance with a target error rate and an allowable throughput; and

assigning a time slot to the first wireless terminal at a data rate corresponding to the allowable throughput in response to determining the number of layers that the wireless first terminal is able to receive.

38. The computer-readable medium of claim 31, further comprising instructions that perform the steps of:

obtaining a signal to noise ratio (SNR) measurement corresponding to a received signal at the first wireless terminal on the wireless channel;

determining a quality of service (QoS) level that is associated with the first wireless terminal; and

converting the SNR measurement and the QoS level to the allowable transmission rate.

39. The computer-readable medium of claim 31, further comprising instructions that perform the steps of:

obtaining a signal to noise ratio (SNR) measurement corresponding to a received signal at the first wireless terminal on the wireless channel;

determining a throughput that is associated with the first wireless terminal; and

converting the SNR measurement and the throughput to the allowable transmission rate.

40. Apparatus for allocating and controlling a transmission rate for a multicast session in a wireless communications system, the multicast session providing a multicast service for a first wireless terminal over a wireless channel, the apparatus comprising:

at least one input/output (I/O) port;

a processor connected to the at least on I/O port in order to communicate with the first wireless terminal, the processor configured to perform the steps of;

(a) receiving a request that the first wireless terminal wishes to join to at least one layer of the multicast service, each layer being associated with a bandwidth requirement;

(b) obtaining a signal to noise (SNR) measurement corresponding to a received signal at the first wireless terminal on the wireless channel;

(c) determining a predicted SNR in response to step (b);

(d) converting the predicted SNR to an allowable transmission rate;

(e) ordering a plurality of wireless terminals in accordance with a corresponding predicted SNR, wherein the plurality of wireless terminals includes the first wireless terminal and wherein the corresponding predicted SNR is associated with each wireless terminal;

(f) determining a number of layers that the first wireless terminal is able to receive in response to step (d);

(g) assigning at least one time slot to the first wireless terminal in response to steps (e) and step (f);

(h) signaling at least one link-level multicast address to the first wireless terminal in order to assign the at least one layer to the first wireless terminal in response to step (g); and

(i) scheduling packets on the at least one time slot corresponding to the at least one layer.

41. The apparatus of claim 40, wherein the processor is configured to perform the further step of:

(j) repeating steps (b) to (h) based upon updates of the allowable transmission rate for the first wireless terminal.

42. The apparatus of claim 41, wherein the updates result from a change in a factor selected from the group consisting of a signal quality, an occurrence of joining the multicast service, and occurrence of leaving the multicast service, and an available fraction of a link capacity

43. A wireless terminal that supports a multicast service over a wireless channel in a wireless communications system, the wireless terminal comprising:

a wireless interface; and

a processor that connects to the wireless interface in order to communicate over the wireless channel and that connects to the memory, the processor configured to perform the steps of;

(a) sending a request that the wireless terminal wishes to join to at least one requested layer corresponding to a multicast group of the multicast service;

(b) sending bandwidth requirements for the at least one requested layer in response to step (a);

(c) sending at least one signal to noise measurement corresponding to a received signal over the wireless channel; and

(d) receiving a multicast session that comprises layers in which the wireless terminal can receive the layers in accordance with a target error rate corresponding to the at least one signal to noise measurement.

44. A method of transmitting a performance to a plurality of mobile terminals, comprising the steps of:

(1) generating a plurality of data streams each comprising one or more components of the performance, wherein each of the data streams is transmitted at a different bandwidth;

(2) receiving from each of the plurality of mobile terminals signal quality information; and

(3) assigning for transmission to each of the respective mobile terminals one of the plurality of data streams based on the received signal quality information, wherein data streams having a higher bandwidth are assigned to mobile terminals having a higher signal quality.

45. The method of claim 44, wherein step (1) comprises the step of generating a plurality of data streams including a first data stream comprising audio information, a second data stream comprising reduced quality video information, and a third data stream comprising high quality video information.

46. The method of claim 44, wherein step (3) comprises the step of assigning a different multicast group address to each of the plurality of data streams, such that each mobile terminal joins one of a plurality of multicast groups based on the received signal quality information.

47. The method of claim 44, wherein the received signal quality information comprises a data error rate.

48. The method of claim 45, wherein step (3) comprises the step of assigning at least two of the plurality of data streams to at least one of the plurality of mobile terminals.