IP Library Granted Patent US 9,936,414
Granted Patent B2
US 9,936,414 · App. 15/270,864 · Granted Apr 3, 2018

Enabling long-term-evolution/wifi coexistence

Inventors: Eugene Chai (Monmouth Junction, NJ); Mohammad Khojastepour (Lawrenceville, NJ); Sampath Rangarajan (Bridgewater, NJ); Karthikeyan Sundaresan (Manalapan, NJ); Krishna Garikipati (Ann Arbor, MI)
Assignee: NEC Corporation
H04W24/10H04W16/14H04W48/18H04W72/0446H04W72/082H04W74/0816H04W72/1215H04W84/042H04W84/12
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Quick Facts
Patent No.
US 9,936,414
App. No.
15/270,864
Granted
Apr 3, 2018
Kind
B2
Abstract

Systems and methods for improving Long Term Evolution (LTE)-WiFi coexistence in a network, including configuring one or more LTE nodes for asynchronous access and synchronous transmission to bridge LTE and WiFi access modes. A channel is reserved for LTE transmission in the one or more LTE nodes, and a supplementary WiFi module is provided in the one or more LTE nodes for sensing the channel for occupancy and for broadcasting a reservation signal on the channel prior to the LTE transmission. Contention window sizes are scaled linearly by increasing the contention window sizes proportionally to a subframe collision rate to maintain throughput fairness to the WiFi, and synchronous transmission from the one or more LTE nodes to one or more User Devices (UEs) is performed by activating the unlicensed carrier for a reserved time period.

Claims (35)

1. A computer implemented method for improving Long Term Evolution (LTE)-WiFi coexistence in a network, comprising:

configuring one or more LTE nodes for asynchronous access and synchronous transmission to bridge LTE and WiFi access modes;

reserving a channel for LTE transmission in the one or more LTE nodes;

providing a supplementary WiFi module in the one or more LTE nodes for sensing the channel for occupancy and for broadcasting a reservation signal on the channel prior to the LTE transmission;

scaling contention window sizes linearly by increasing the contention window sizes proportionally to a subframe collision rate to maintain throughput fairness to the WiFi; and

performing synchronous transmission from the one or more LTE nodes to one or more User Devices (UEs) by activating the unlicensed carrier for a reserved time period.

2. The method of claim 1 , further comprising identifying UEs to schedule on unlicensed carriers by measuring frame loss rates for each UE to determining a susceptibility of the UE to interference.

3. The method of claim 1 , wherein the reserved time period is a duration of the LTE transmission.

4. The method of claim 1 , wherein the reservation signal broadcast from the WiFi module includes a Clear-to-Send (CTS)-to-Self packet with a Network Allocation Vector (NAV) field set to a duration of the LTE transmission.

5. The method of claim 1 , wherein the WiFi module at the one or more LTE node senses the channel for on-going transmissions to determine an appropriate time to initiate the LTE transmission.

6. The method of claim 1 , further comprising sorting a set of a plurality of the UEs according to frame loss rates of individual UEs.

7. The method of claim 6 , wherein subframe resources in an unlicensed control carrier are assigned to the UEs in increasing order of the frame loss rates of individual UEs.

8. The method of claim 1 , further comprising extending a channel reservation by inserting successive Clear-to-Send (CTS)-to-Self frames.

9. The method of claim 1 , further comprising providing time gaps in a last LTE downlink subframe by avoiding scheduling any data transmission in the last LTE downlink subframe.

10. A system for improving Long Term Evolution (LTE)-WiFi coexistence in a network, comprising:

one or more LTE nodes configured for asynchronous access and synchronous transmission to bridge LTE and WiFi access modes;

a channel scheduler for reserving a channel for LTE transmission in the one or more LTE nodes;

a supplementary WiFi module in the one or more LTE nodes for sensing the channel for occupancy and for broadcasting a reservation signal on the channel prior to the LTE transmission;

a scaler for scaling contention window sizes linearly by increasing the contention window sizes proportionally to a subframe collision rate to maintain throughput fairness to the WiFi; and

a transmitter for performing synchronous transmission from the one or more LTE nodes to one or more User Devices (UEs) by activating the unlicensed carrier for a reserved time period.

11. The system of claim 10 , further comprising an interference detector for identifying UEs to schedule on unlicensed carriers by measuring frame loss rates for each UE to determining a susceptibility of the UE to interference.

12. The system of claim 10 , wherein the reserved time period is a duration of the LTE transmission.

13. The system of claim 10 , wherein the reservation signal broadcast from the WiFi module includes a Clear-to-Send (CTS)-to-Self packet with a Network Allocation Vector (NAV) field set to a duration of the LTE transmission.

14. The system of claim 10 , wherein the WiFi module at the one or more LTE node senses the channel for on-going transmissions to determine an appropriate time to initiate the LTE transmission.

15. The system of claim 10 , wherein the channel scheduler is further configured to sort a set of a plurality of the UEs according to frame loss rates of individual UEs.

16. The system of claim 15 , wherein subframe resources in an unlicensed control carrier are assigned to the UEs in increasing order of the frame loss rates of individual UEs.

17. The system of claim 10 , wherein the scaler is further configured to extend a channel reservation by inserting successive Clear-to-Send (CTS)-to-Self frames.

18. The system of claim 10 , wherein the channel scheduler is further configured to provide time gaps in a last LTE downlink subframe by avoiding scheduling any data transmission in the last LTE downlink subframe.

19. A non-transitory computer-readable storage medium comprising a computer-readable program for improving Long Term Evolution (LTE)-WiFi coexistence in a network, wherein the computer-readable program when executed on a computer causes the computer to perform the steps of:

configuring one or more LTE nodes for asynchronous access and synchronous transmission to bridge LTE and WiFi access modes;

reserving a channel for LTE transmission in the one or more LTE nodes;

providing a supplementary WiFi module in the one or more LTE nodes for sensing the channel for occupancy and for broadcasting a reservation signal on the channel prior to the LTE transmission;

scaling contention window sizes linearly by increasing the contention window sizes proportionally to a subframe collision rate to maintain throughput fairness to the WiFi; and

performing synchronous transmission from the one or more LTE nodes to one or more User Devices (UEs) by activating the unlicensed carrier for a reserved time period.

20. The computer-readable storage medium of claim 19 , further comprising identifying UEs to schedule on unlicensed carriers by measuring frame loss rates for each UE to determining a susceptibility of the UE to interference.

Assignments (2)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Feb 14, 2018
From: NEC LABORATORIES AMERICA, INC.
To: NEC CORPORATION
Reel/Frame 044928/0569 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Sep 20, 2016
From: CHAI, EUGENE; KHOJASTEPOUR, MOHAMMAD; RANGARAJAN, SAMPATH; SUNDARESAN, KARTHIKEYAN; GARIKIPATI, KRISHNA
To: NEC LABORATORIES AMERICA, INC.
Reel/Frame 039804/0848 →
Continuity (2)
Provisional Application 62232911 · Sep 25, 2015
Related Publication 20170094546A1 · Mar 30, 2017