Channel feedback for TDM scheduling in heterogeneous networks having multiple cell classes

• US 8,861,391 B1
• Filed: 03/01/2012
• Issued: 10/14/2014
• Est. Priority Date: 03/02/2011
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell International Limited (Marvell Technology Group Limited)
• Inventors: Zhang, Yan, Gomadam, Krishna Srikanth
• Primary Examiner(s): Ton, Dang
• Assistant Examiner(s): AMBAYE, MEWALE A
• Application Number:
  US13/409,130
• Time in Patent Office: 957 Days
• Field of Search: 370/252, 375/219, 375/260, 375/267, 375/316, 375/299
• US Class Current: 370/252
• CPC Class Codes: H04B 7/0619 using feedback from receiving side feedback signaling for adaptive modulation/coding H04L1/0001
• CPC Class Codes: H04L 1/0007 by modifying the frame length
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 25/03949 equalizer selection or adaptation based on feedback multiple signaling inclusive of a precoding command for adapting the transmitter H04L1/0031; feedback for transmit diversity systems H04B7/0619; selection of codebook or precoding matrix for MIMO diversity systems H04B7/0456
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A method includes receiving in a communication terminal a sequence of downlink frames from a communication network that includes multiple cells arranged in first and second layers. The first layer corresponds to a first class of cells selected from a group of classes consisting of macro-cells, micro-cells, pico-cells, femto-cells and low-power nodes (LPN). The second layer corresponds to a second class of cells, different from the first class. One or more cross-layer frames in which at least a first cell in the first layer and at least a second cell in the second layer transmit data, and one or more same-layer frames in which only one or more of the cells in a single layer that currently serves the terminal transmit the data, are identified in the sequence. Cross-layer channel feedback is calculated over the cross-layer frames, and same-layer channel feedback is calculated over the same-layer frames.

Claims

1. A method, comprising:

receiving in a mobile communication terminal a sequence of downlink frames from a communication network that includes multiple cells arranged in at least first and second layers, wherein the first layer corresponds to a first class of the cells selected from a group of classes consisting of macro-cells, micro-cells, pico-cells, femto-cells and low-power nodes (LPN), and wherein the second layer corresponds to a second class of the cells that is different from the first class;

identifying in the sequence one or more cross-layer frames in which at least a first cell in the first layer and at least a second cell in the second layer transmit data;

identifying in the sequence one or more same-layer frames in which only one or more of the cells in a single layer that currently serves the terminal transmit the data;

calculating cross-layer channel feedback over the cross-layer frames, and calculating same-layer channel feedback over the same-layer frames; and

transmitting the cross-layer channel feedback and the same-layer channel feedback from the terminal.

2. The method according to claim 1, wherein calculating the cross-layer channel feedback and the same-layer channel feedback comprises calculating a cross-layer Signal to Interference and Noise Ratio (SINR) over the received cross-layer frames, calculating a same-layer SINR over the received same-layer frames, and calculating the cross-layer channel feedback and the same-layer channel feedback based on the cross-layer SINR and the same-layer SINR, respectively.

3. The method according to claim 1, wherein calculating the cross-layer channel feedback and the same-layer channel feedback comprises calculating a cross-layer covariance matrix over the received cross-layer frames, calculating a same-layer covariance matrix over the received same-layer frames, and calculating the cross-layer channel feedback and the same-layer channel feedback based on the cross-layer covariance matrix and the same-layer covariance matrix, respectively.

4. The method according to claim 1, wherein transmitting the cross-layer channel feedback and the same-layer channel feedback comprises sending both the cross-layer channel feedback and the same-layer channel feedback in a single uplink frame.

5. The method according to claim 1, wherein transmitting the cross-layer channel feedback and the same-layer channel feedback comprises interleaving the cross-layer channel feedback and the same-layer channel feedback in alternate uplink frames.

6. The method according to claim 1, wherein transmitting the cross-layer channel feedback and the same-layer channel feedback comprises transmitting the cross-layer channel feedback at a first update rate, and transmitting the same-layer channel feedback at a second update rate, different from the first update rate.

7. The method according to claim 1, wherein transmitting the cross-layer channel feedback and the same-layer channel feedback comprises compressing one or both of the cross-layer channel feedback and the same-layer channel feedback prior to transmission.

8. The method according to claim 1, wherein receiving the downlink frames comprises receiving downlink sub-frames in accordance with a Long Term Evolution (LTE) specification.

9. The method according to claim 1, wherein identifying the cross-layer frames and the same-layer frames comprises automatically detecting a predefined periodic pattern which the cells transmit using the cross-layer frames and the same-layer frames.

10. The method according to claim 1, wherein receiving the sequence comprises receiving the downlink frames from no layer other than the first and second layers.

11. The method according to claim 1, wherein receiving the sequence comprises receiving the downlink frames from three or more layers in which the cells are arranged.

12. The method according to claim 11, wherein identifying the cross-layer frames comprises identifying two or more different types of the cross-layer frames, corresponding to respective different subsets of the layers whose cells are permitted to transmit during the cross-layer frames, and wherein calculating the cross-layer channel feedback comprises computing the cross-layer channel feedback separately for each type of the cross-layer frames.

13. Apparatus, comprising:

a receiver, which is configured to receive a sequence of downlink frames from a communication network that includes multiple cells arranged in at least first and second layers, wherein the first layer corresponds to a first class of the cells selected from a group of classes consisting of macro-cells, micro-cells, pico-cells, femto-cells and low-power nodes (LPN), and wherein the second layer corresponds to a second class of the cells that is different from the first class;

control circuitry, which is configured to identify in the sequence one or more cross-layer frames in which at least a first cell in the first layer and at least a second cell in the second layer transmit data, to identify in the sequence one or more same-layer frames in which only one or more of the cells in a single layer that currently serves the apparatus transmit the data, to calculate cross-layer channel feedback over the cross-layer frames, and to calculate same-layer channel feedback over the same-layer frames; and

a transmitter, which is configured to transmit the cross-layer channel feedback and the same-layer channel feedback to the communication network.

14. The apparatus according to claim 13, wherein the control circuitry is configured to calculate a cross-layer Signal to Interference and Noise Ratio (SINR) over the received cross-layer frames, to calculate a same-layer SINR over the received same-layer frames, and to calculate the cross-layer channel feedback and the same-layer channel feedback based on the cross-layer SINR and the same-layer SINR, respectively.

15. The apparatus according to claim 13, wherein the control circuitry is configured to calculate a cross-layer covariance matrix over the received cross-layer frames, to calculate a same-layer covariance matrix over the received same-layer frames, and to calculate the cross-layer channel feedback and the same-layer channel feedback based on the cross-layer covariance matrix and the same-layer covariance matrix, respectively.

16. The apparatus according to claim 13, wherein the transmitter is configured to transmit both the cross-layer channel feedback and the same-layer channel feedback in a single uplink frame.

17. The apparatus according to claim 13, wherein the transmitter is configured to interleave the cross-layer channel feedback and the same-layer channel feedback in alternate uplink frames.

18. The apparatus according to claim 13, wherein the transmitter is configured to transmit the cross-layer channel feedback at a first update rate, and to transmit the same-layer channel feedback at a second update rate, different from the first update rate.

19. The apparatus according to claim 13, wherein the control circuitry is configured to compress one or both of the cross-layer channel feedback and the same-layer channel feedback prior to transmission.

20. The apparatus according to claim 13, wherein the receiver is configured to receive from the communication network downlink sub-frames in accordance with a Long Term Evolution (LTE) specification.

21. The apparatus according to claim 13, wherein the control circuitry is configured to identify the cross-layer frames and the same-layer frames by automatically detecting a predefined periodic pattern which the cells transmit using the cross-layer frames and the same-layer frames.

22. The apparatus according to claim 13, wherein the receiver is configured to receive the downlink frames from no layer other than the first and second layers.

23. The apparatus according to claim 13, wherein the receiver is configured to receive the downlink frames from three or more layers in which the cells are arranged.

24. The apparatus according to claim 23, wherein the control circuitry is configured to identify two or more different types of the cross-layer frames, corresponding to respective different subsets of the layers whose cells are permitted to transmit during the cross-layer frames, and to calculate the cross-layer channel feedback separately for each type of the cross-layer frames.

25. A mobile communication terminal comprising the apparatus of claim 13.

26. A chipset for processing signals in a mobile communication terminal, comprising the apparatus of claim 13.