Methods for long term evolution (LTE) transmission bursts to improve spectral efficiency in unlicensed frequency channels and indoor scenarios

• US 10,014,991 B2
• Filed: 10/13/2015
• Issued: 07/03/2018
• Est. Priority Date: 11/07/2014
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Chandrasekhar, Vikram, Seymour, James, Pazhyannur, Rajesh, Myles, Andrew
• Primary Examiner(s): Orgad, Edan
• Assistant Examiner(s): Shah, Saumit
• Application Number:
  US14/881,479
• Publication Number:
  US 20160135185A1
• Time in Patent Office: 994 Days
• Field of Search: None
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0032 Distributed allocation, i.e. involving a plurality of allocating devices, each making partial allocation
• CPC Class Codes: H04L 5/0044 allocation of payload
• CPC Class Codes: H04L 5/0071 Allocation based on fairness other than the proportional kind
• CPC Class Codes: H04L 5/0087 when data requirements change
• CPC Class Codes: H04L 5/0091 Signaling for the administration of the divided path
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 72/1263 Mapping of traffic onto schedule, e.g. scheduled allocation or multiplexing of flows
• CPC Class Codes: H04W 72/20 Control channels or signalling for resource management

Abstract

Modifications to frame/subframe structure are presented herein so that a wireless device can transmit its data within a fraction of a subframe. The device obtains data to be transmitted in an unlicensed spectrum and determines whether an entire subframe is required to completely communicate the data. If the data is small enough to not require the entire subframe, then the device generates a burst transmission to minimize the time period of the subframe used to communicate the data. The device transmits the burst transmission and a parameter indicating the duration of the burst transmission.

Claims

1. A method comprising:

obtaining data to be wirelessly transmitted in a frame in an unlicensed spectrum;

determining whether an entire subframe of the frame is required to completely communicate the data;

responsive to determining that the data does not require the entire subframe, generating a burst transmission so as to minimize a time period of the subframe used to communicate the data by increasing a subcarrier spacing and decreasing a symbol transmission time;

transmitting an indication of the subcarrier spacing via one or more channels in a licensed spectrum; and

transmitting the burst transmission and a parameter indicating a duration of the burst transmission via the unlicensed spectrum.

2. The method of claim 1, further comprising muting a transmitter following completion of the transmission burst until an end-boundary of the subframe.

3. The method of claim 1, further comprising determining whether the unlicensed spectrum is clear to transmit the frame.

4. The method of claim 1, further comprising muting a remainder of the subframe after the time period used to communicate the data.

5. The method of claim 4, wherein the parameter is transmitted within the subframe and is an indication of the time period used to communicate the data.

6. The method of claim 5, wherein the indication of the time period used to communicate the data is transmitted in an initial symbol of the burst transmission.

7. The method of claim 5, wherein the frame is a Long Term Evolution (LTE) frame, and wherein the indication of the time period used to communicate the data is transmitted as part of a Physical Downlink Control Channel (PDCCH) or an Enhanced Physical Downlink Control Channel (EPDCCH).

8. The method of claim 7, wherein the indication of the time period used to communicate the data is transmitted as a two bit message in the PDCCH or the EPDCCH.

9. The method of claim 1, wherein increasing the subcarrier spacing comprises utilizing the full extent of the unlicensed spectrum for the transmission burst.

10. An apparatus comprising:

a transmitter configured to transmit signals in an unlicensed spectrum and a licensed spectrum;

a modem configured to modulate signals for transmission in a frame;

a processor configured to;

obtain data to be wirelessly transmitted by the transmitter;

determine whether an entire subframe of the frame is required to completely communicate the data;

responsive to determining that the data does not require the entire subframe, generate a burst transmission so as to minimize a time period of the subframe used to communicate the data by increasing a subcarrier spacing and decreasing a symbol transmission time;

cause the transmitter to transmit an indication of the subcarrier spacing via one or more channels in the licensed spectrum; and

cause the transmitter to transmit the burst transmission and a parameter indicating a duration of the burst transmission via the unlicensed spectrum.

11. The apparatus of claim 10, wherein the processor is further configured to determine whether the unlicensed spectrum is clear to transmit the frame.

12. The apparatus of claim 10, wherein the processor is configured to mute the transmitter after the time period used to communicate the data.

13. The apparatus of claim 12, wherein the processor is further configured to cause the transmitter to transmit the parameter indicating the duration of the burst transmission within the subframe, wherein the parameter is an indication of the time period used to communicate the data in an initial symbol of the burst transmission.

14. The apparatus of claim 12, wherein the frame is a Long Term Evolution (LTE) frame, and wherein the processor is further configured to cause the transmitter to transmit an indication of the time period used to communicate the data in the burst transmission as part of a Physical Downlink Control Channel (PDCCH) or an Enhanced Physical Downlink Control Channel (EPDCCH).

15. The apparatus of claim 10, wherein the processor is configured to increase the subcarrier spacing to utilize the full extent of the unlicensed spectrum for the transmission burst.

16. One or more non-transitory computer readable storage media encoded with software comprising computer executable instructions and when the software is executed operable to cause a processor to:

obtain data to be wirelessly transmitted in a frame in an unlicensed spectrum;

determine whether an entire subframe of the frame is required to completely communicate the data;

responsive to determining that the data does not require the entire subframe, generate a burst transmission so as to minimize a time period of the subframe used to communicate the data by increasing a subcarrier spacing and decreasing a symbol transmission time;

cause a transmitter to transmit an indication of the subcarrier spacing via one or more channels in a licensed spectrum; and

cause the transmitter to transmit the burst transmission and a parameter indicating a duration of the burst transmission via the unlicensed spectrum.

17. The computer readable storage media of claim 16, wherein the instructions cause the processor to determine whether the unlicensed spectrum is clear to transmit the frame.

18. The computer readable media of claim 16, wherein the instructions cause the processor to mute the transmitter after the time period used to communicate the data.

19. The computer readable storage media of claim 18, wherein the instructions further cause the transmitter to transmit the parameter indicating the duration of the burst transmission within the subframe, and wherein the parameter is an indication of the time period used to communicate the data in an initial symbol of the burst transmission.

20. The computer readable storage media of claim 18, wherein frame is a Long Term Evolution (LTE) frame and wherein the instructions further cause the transmitter to transmit an indication of the time period used to communicate the data in the burst transmission as part of a Physical Downlink Control Channel (PDCCH) or an Enhanced Physical Downlink Control Channel (EPDCCH).

21. The computer readable storage media of claim 16, wherein the instructions cause the processor to increase the subcarrier spacing to utilize the full extent of the unlicensed spectrum for the transmission burst.