System and Method for Small Traffic Transmissions

• US 20140192767A1
• Filed: 06/06/2013
• Published: 07/10/2014
• Est. Priority Date: 12/14/2012
• Status: Abandoned Application

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Inventors: Au, Kelvin Kar Kin, Ma, Jianglei, Nikopour, Hosein, Bayesteh, Alireza, Djukic, Petar, Zhang, Liqing, Zhu, Peiying
• Application Number:
  US13/911,716
• Publication Number:
  US 20140192767A1
• Time in Patent Office: Days
• US Class Current: 370/330
• CPC Class Codes: H04L 1/0045 Arrangements at the receiver end
• CPC Class Codes: H04W 72/0466 the resource being a scrambling code
• CPC Class Codes: H04W 72/21 in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 72/23 in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 74/0866 using a dedicated channel for access

Abstract

A grant-free transmission mode may be used to communicate small traffic transmissions to reduce overhead and latency. The grant-free transmission mode may be used in downlink and uplink data channels of a wireless network. In the downlink channel, a base station transmits packets to a group of UEs in a search space without communicating any transmission code assignments to the UEs. The UEs receive the downlink packets using blind detection. In the uplink channel, UEs transmit packets in an access space using assigned access codes which are either independently derived by the UEs or otherwise communicated by the base station using a slow-signaling channel. Hence, the grant-free transmission mode allows mobile devices to make small traffic transmissions without waiting for uplink grant requests.

Claims

1. A method comprising:

allocating, by a base station, resources of a downlink channel as a search space for a group of mobile devices;

assigning a first transmission code to a first mobile device; and

transmitting, by the base station, a packet over the resources in accordance with the first transmission code without communicating transmission code assignments to the first mobile device, wherein the first mobile device is configured to receive the packet using blind detection.

2. The method of claim 1, wherein the first transmission code comprises an orthogonal or quasi-orthogonal signature.

3. The method of claim 2, wherein the first transmission code comprises at least one of a low density signature, a code division multiple access (CDMA) signature, a pseudo noise (PN) sequence, a Zadoff-Chu sequence, and a Walsh-Hadamard code.

4. The method of claim 2, wherein the first transmission code comprises a sparse multiple access code.

5. The method of claim 1, wherein the packet includes at least some data that is not control information.

6. The method of claim 1, wherein transmitting the packet over the resources of the downlink channel comprises:

transmitting the packet in accordance with multiple transmission codes.

7. The method of claim 1, wherein the search space comprises time-frequency resources of the downlink channel.

8. The method of claim 1, wherein the search space comprises spatial resources of the downlink channel.

9. A base station comprising:

a processor; and

a computer readable storage medium storing programming for execution by the processor, the programming including instructions to;

allocate time-frequency resources as a search space for a group of mobile devices;

assign a first transmission code to a first mobile device; and

transmit a first packet over the resources in accordance with the first transmission code without communicating any transmission code assignments to the first mobile device, wherein the first mobile device is configured to receive the first packet using blind detection.

10. A method comprising:

identifying a search space for a group of mobile devices, the group of mobile device including at least a first mobile device, wherein the search space comprises resources of a downlink channel;

determining a set of candidate transmission codes associated with the search space; and

receiving, by the first mobile device, a packet communicated in the search space using blind detection, wherein the packet is communicated in accordance with a first transmission code in the set of candidate transmission codes.

11. The method of claim 10, wherein receiving the packet using blind detection comprises:

receiving, by the first mobile device, the packet without knowing beforehand which transmission code in the set of candidate transmission codes was used to communicate the packet.

12. The method of claim 10, wherein receiving the packet using blind detection comprises:

decoding, by the first mobile device, a plurality of packets communicated in the search space using a corresponding transmission code in the set of candidate transmission codes, wherein each packet is communicated in accordance with a different transmission code in the set of candidate transmission codes; and

determining which of the decoded packets carries an identifier associated with the first mobile device.

13. The method of claim 10, wherein the search space comprises time-frequency resources of the downlink channel.

14. The method of claim 10, wherein the search space comprises spatial resources of the downlink channel.

15. A mobile device comprising:

a processor; and

a computer readable storage medium storing programming for execution by the processor, the programming including instructions to;

identify a search space for a group of mobile devices associated with the mobile device, the search space comprising resources of a downlink channel;

determine a set of candidate transmission codes associated with the search space; and

receive a packet communicated in the search space using blind detection, wherein the packet is communicated in accordance with a first transmission code in the set of candidate transmission codes.

16. A method comprising:

identifying an access space for a group of mobile devices, the access space comprising resources of an uplink channel, wherein the group of mobile devices comprise at least a first mobile device;

determining a first transmission code in a set of transmission codes for the first mobile device; and

transmitting, by the first mobile device, a packet over the resources of the uplink channel using the first transmission code without obtaining an uplink grant.

17. The method of claim 16, wherein the first transmission code comprises an orthogonal or quasi-orthogonal signature.

18. The method of claim 17, wherein the first transmission code comprises at least one of a low density signature, a code division multiple access (CDMA) signature, a pseudo noise (PN) sequence, a Zadoff-Chu sequence, and a Walsh-Hadamard code.

19. The method of claim 17, wherein the first transmission code comprises a sparse multiple access code.

20. The method of claim 16, wherein the first transmission code is assigned exclusively to the first mobile device without being assigned to other mobile devices in the group of mobile devices.

21. The method of claim 16, wherein the first transmission code is assigned to multiple mobile devices in the group of mobile devices.

22. The method of claim 16, wherein transmitting the packet over the resources using the first transmission code comprises:

transmitting, by the first mobile device, the packet over the resources of the uplink channel using the first transmission code; and

re-transmitting the packet if a collision resulted from the earlier transmission.

23. The method of claim 16, wherein determining the first transmission code for the first mobile device comprises:

independently deriving the first transmission code by the first mobile device in accordance with a connection signature of the first mobile device.

24. The method of claim 16, wherein determining the first transmission code for the first mobile device comprises:

receiving, by the first mobile, a transmission code assignment over a slow-signaling channel, the slow-signaling channel being communicated less frequently than a control channel used to communicate uplink grant information.

25. The method of claim 16, wherein the access space comprises time-frequency resources of the uplink channel.

26. The method of claim 16, wherein the access space comprises spatial resources of the uplink channel.

27. A mobile station comprising:

a processor; and

a computer readable storage medium storing programming for execution by the processor, the programming including instructions to;

identify an access space for a group of mobile stations, the access space comprising resources of an uplink channel, wherein the group of mobile stations comprises at least a first mobile station;

determine that a first transmission code in a set of transmission codes has been assigned to the first mobile station; and

transmit a packet over the resources of the uplink channel using the first transmission code without obtaining an uplink grant.

28. A method comprising:

identifying an access space for a group of mobile devices, the access space comprising resources of an uplink channel;

identifying a set of transmission codes associated with access space; and

receiving, by a base station, packets communicated over the resources of the uplink channel using blind detection.

29. The method of claim 28, wherein the packets are received without communicating uplink grant information to the group of mobile devices.

30. A base station comprising:

a processor; and

a computer readable storage medium storing programming for execution by the processor, the programming including instructions to;

identify an access space for a group of mobile devices, the access space comprising resources of an uplink channel;

identify a set of transmission codes associated with access space; and

receive packets communicated over the resources of the uplink channel using blind detection.

31. A method comprising:

communicating capability information between a mobile device and a base station, the capability information indicating a grant-free communication mode capability; and

communicating grant-free signaling parameters between the mobile device and the base station, the grant-free signaling parameters defining a search space or an access space for the grant-free communication mode.

32. The method of claim 31, wherein the grant-free communication mode capability indicates that the base station supports grant-free communications over an uplink or downlink channel.

33. The method of claim 31, wherein the grant-free communication mode capability indicates that the mobile device is capable of performing grant-free communications over an uplink channel, receiving grant-free communications over a downlink channel, or both.

34. The method of claim 31, wherein communicating grant-free signaling parameters between the mobile device and the base station comprises:

communicating the grant-free signaling parameters over a slow-signaling channel, the slow-signaling channel being communicated less frequently than a control channel used to communicate uplink grant information.

35. The method of claim 31, wherein the grant-free signaling parameters include a set of candidate transmission codes.