Evolved node-B and methods for supporting co-existence with Wi-Fi networks in an unlicensed frequency band

• US 9,801,207 B2
• Filed: 08/29/2014
• Issued: 10/24/2017
• Est. Priority Date: 11/27/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Intel Corporation
• Inventors: Sergeyev, Vadim, Bashar, Shafi, Davydov, Alexei, Fwu, Jong-Kae
• Primary Examiner(s): Yeung, Mang
• Assistant Examiner(s): Solinsky, Peter G
• Application Number:
  US14/473,008
• Publication Number:
  US 20150146645A1
• Time in Patent Office: 1,152 Days
• Field of Search: 370329
• CPC Class Codes: H04B 7/2621 using frequency division multiple access [FDMA] H04B7/2615 takes precedence
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/1825 Adaptation of specific ARQ protocol parameters according to transmission conditions
• CPC Class Codes: H04L 27/2607 Cyclic extensions
• CPC Class Codes: H04L 47/25 with rate being modified by the source upon detecting a change of network conditions
• 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 5/0051 of dedicated pilots, i.e. pilots destined for a single user or terminal
• CPC Class Codes: H04L 5/0073 Allocation arrangements that take into account other cell interferences for intercell interference mitigation or co-ordination in orthogonal multiplex systems H04J11/005
• CPC Class Codes: H04L 5/0078 Timing of allocation
• CPC Class Codes: H04L 5/14 Two-way operation using the same type of signal, i.e. duplex
• CPC Class Codes: H04L 5/1469 using time-sharing
• CPC Class Codes: H04L 5/22 using time-division multiplexing
• CPC Class Codes: H04L 69/161 Implementation details of TCP/IP or UDP/IP stack architecture; Specification of modified or new header fields
• CPC Class Codes: H04L 69/163 In-band adaptation of TCP data exchange; In-band control procedures
• CPC Class Codes: H04L 69/321 Interlayer communication protocols or service data unit [SDU] definitions; Interfaces between layers
• CPC Class Codes: H04L 69/324 in the data link layer [OSI layer 2], e.g. HDLC
• CPC Class Codes: H04L 69/326 in the transport layer [OSI layer 4] H04L69/16 takes precedence
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 16/24 Cell structures
• CPC Class Codes: H04W 28/0205 : at the air interface dynamic wireless traffic scheduling H04W72/12
• CPC Class Codes: H04W 36/0069 : in case of dual connectivity, e.g. decoupled uplink/downlink
• CPC Class Codes: H04W 36/0083 : Determination of parameters used for hand-off, e.g. generation or modification of neighbour cell lists
• CPC Class Codes: H04W 40/30 : for proactive routing
• CPC Class Codes: H04W 52/0216 : using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/0254 : detecting a user operation or a tactile contact or a motion of the device
• CPC Class Codes: H04W 72/02 : Selection of wireless resources by user or terminal
• CPC Class Codes: H04W 72/0446 : Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/0453 : Resources in frequency domain, e.g. a carrier in FDMA
• 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 72/51 : based on terminal or device properties
• CPC Class Codes: H04W 74/04 : Scheduled access hybrid access H04W74/02
• CPC Class Codes: H04W 76/27 : Transitions between radio resource control [RRC] states
• CPC Class Codes: H04W 76/28 : Discontinuous transmission [DTX]; Discontinuous reception [DRX]
• CPC Class Codes: H04W 80/06 : Transport layer protocols, e.g. TCP [Transport Control Protocol] over wireless transmission control protocol/Internet protocol [TCP/IP] or user datagram protocol [UDP] H04L69/16
• CPC Class Codes: H04W 84/12 : WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/06 : adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals
• CPC Class Codes: H04W 88/10 : adapted for operation in multiple networks, e.g. multi-mode access points
• CPC Class Codes: Y02D 30/50 : in wire-line communication networks, e.g. low power modes or reduced link rate
• CPC Class Codes: Y02D 30/70 : in wireless communication networks

Abstract

Embodiments of an eNB and method for supporting communication with UEs on an LTE network in an unlicensed frequency band are generally described herein. The eNB may be configured to transmit a first LTE signal that includes a first reference signal during an active transmission period of a Wi-Fi network in the unlicensed frequency band, and to restrict frequency spectra used for the transmission of the first LTE signal from frequency spectra used by the Wi-Fi network during the active transmission period. The first reference signal may enable maintenance of synchronization between the eNB and the UEs at least during the active transmission period. The eNB may be further configured to transmit a second LTE signal during a silence period of the Wi-Fi network in frequency spectra used by the Wi-Fi network during the active transmission period.

Claims

1. An Evolved Node-B (eNB) to communicate with one or more User Equipments (UEs) on a Long Term Evolution (LTE) network operating in an unlicensed frequency band, the eNB comprising:

a transceiver; and

hardware processing circuitry in communication with the transceiver arranged to;

cause the transceiver to transmit, in the unlicensed frequency band, a first LTE signal that includes a first reference signal during an active transmission period of a Wi-Fi network operating in the unlicensed frequency band;

restrict frequency spectra used for the transmission of the first LTE signal from frequency spectra used by the Wi-Fi network during the active transmission period of the Wi-Fi network, wherein the first reference signal enables maintenance of synchronization between the eNB and the one or more UEs at least during the active transmission period of the Wi-Fi network;

cause the transceiver to transmit a second LTE signal during a silence period of the Wi-Fi network, the second LTE signal transmitted in frequency spectra that includes at least a portion of the frequency spectra used by the Wi-Fi network during the active transmission period of the Wi-Fi network, the second LTE signal comprising a second reference signal; and

cause the transceiver to transmit a silence indicator that enables one or more of the UEs to determine an occurrence of at least one of a silence period or an active transmission period of the Wi-Fi network, the active transmission period being a time period that contains a transmission of a Wi-Fi device in the Wi-Fi network and the silence period being a time period that is free from transmission of the Wi-Fi device, the silence indicator comprising at least one of;

a time at which the at least one of the silence period or active transmission period occurs, or

an indication that the Wi-Fi network is currently in the silence period or active transmission period.

2. The eNB according to claim 1, wherein the processing circuitry is further arranged to restrict the frequency spectra by selection of frequency spectra for transmission of the first LTE signal such that an LTE interference average power level caused to the frequency spectra used by the Wi-Fi network for transmission during the active transmission period of the network is not greater than one percent of an average transmit power level of the Wi-Fi network.

3. The eNB according to claim 1, wherein:

the second LTE signal includes a second reference signal that enables determination of channel state information or maintenance of synchronization at the UEs; and

the transmission of the first reference signal is performed at an average power level at least 10 dB higher than the transmission of the second reference signal.

4. The eNB according to claim 3, wherein:

the second LTE signal occupies more bandwidth than the second LTE signal, and to compensate for a bandwidth different, at least one of;

the first reference signal is longer than the second reference signal in time, and

the first reference signal is repeated.

5. The eNB according to claim 3, wherein:

the second LTE signal is transmitted at a higher power than the second LTE signal, and to compensate for a different in transmission power, at least one of;

the first reference signal is longer than the second reference signal in time, and

the first reference signal is repeated.

6. The eNB according to claim 1, wherein:

the first LTE signal is an orthogonal frequency division multiplexing (OFDM) signal comprising first resource elements (REs);

the second LTE signal is an OFDM signal comprising second REs; and

the transmission of the first reference signal includes transmission of first reference signal REs of the first LTE signal and the transmission of the second reference signal includes transmission of second reference signal REs of the second LTE signal.

7. The eNB according to claim 6, wherein:

the transmission of the second LTE signal further includes transmission of a data signal;

the second REs are associated with time and frequency locations; and

the transmission of the data signal includes transmission of data REs of the second REs that are different in time location and frequency location than the second reference signal REs.

8. The eNB according to claim 1, wherein the silence indicator is transmitted in a licensed frequency band that is disjoint from the unlicensed frequency band.

9. The eNB according to claim 1, wherein:

the LTE, and Wi-Fi networks operate independently from each other; and

the hardware processing circuitry is further arranged to determine an occurrence of the silence period or the active transmission period of the Wi-Fi network based at least partially on reception of wireless signals transmitted from one or more Wi-Fi devices operating as part of the Wi-Fi network.

10. The eNB according to claim 1, wherein the hardware processing circuitry is further arranged to:

determine transmission of the Wi-Fi device based at least partially on reception of a wireless signal transmitted from the Wi-Fi device; and

predict the at least one of the silence period or active transmission period from a pattern of the at least one of the silence period or active transmission period based on observations of previous transmissions of wireless signals from the Wi-Fi device along with knowledge about a Wi-Fi protocol used by the Wi-Fi network.

11. The eNB according to claim 1, wherein the first and second LTE signals occupy different amounts of bandwidth.

12. The eNB according to claim 11, wherein the second LTE signal occupies more bandwidth than the second LTE signal.

13. The eNB according to claim 11, wherein the first and second LTE signals have different formats, a format of the first LTE signal based on a bandwidth of the first LTE signal and a bandwidth of the second LTE signal.

14. The eNB according to claim 1, wherein the silence indicator is transmitted in another unlicensed frequency band that is different from the unlicensed frequency band.

15. The eNB according to claim 1, wherein the hardware processing circuitry is further configured to determine on which band to transmit the silence indicator based on an amount of traffic on the licensed frequency band.

16. The eNB according to claim 1, wherein:

the frequency spectra used by the Wi-Fi network during the active transmission period of the Wi-Fi network comprises a gap at at least one edge of the unlicensed frequency band, and the hardware processing circuitry is further configured to cause the transceiver to transmit the first LTE signal in the gap.

17. An Evolved Node-B (eNB) to communicate with one or more User Equipments (UEs) on a Long Term Evolution (LTE) network operating in an unlicensed frequency band, the eNB comprising:

a transceiver; and

hardware processing circuitry in communication with the transceiver and arranged to;

when it is determined that one or more Wi-Fi networks are operating in the unlicensed frequency band;

cause the transceiver to transmit a first LTE signal in the unlicensed frequency band during a silence period associated with the Wi-Fi networks;

cause the transceiver to refrain from transmitting LTE signals in the unlicensed frequency band used by the Wi-Fi network during an active transmission period associated with the Wi-Fi networks, the LTE signals transmitted in the unlicensed frequency band during the active transmission period, wherein the first LTE signal includes a first reference signal that enables maintenance of synchronization between the eNB and the UEs;

when it is determined that Wi-Fi networks are not operating in the unlicensed frequency band, cause the transceiver to transmit a second LTE signal during periodic time intervals according to a periodicity parameter, the second LTE signal comprising a second reference signal; and

cause the transceiver to transmit a silence indicator that enables one or more of the UEs to determine an occurrence of at least one of the silence period or an active transmission period of the Wi-Fi network, the active transmission period being a time period that contains a transmission of a Wi-Fi device in the Wi-Fi network and the silence period being a time period that is free from transmission of the Wi-Fi device, the silence indicator comprising at least one of;

a time at which the at least one of the silence period or active transmission period occurs, or

an indication that the Wi-Fi network is currently in the silence period or active transmission period.

18. The eNB according to claim 17, wherein:

the first LTE signal is an orthogonal frequency division multiplexing (OFDM) signal comprising first resource elements (REs); and

the first reference signal occupies first reference signal REs of the first REs.

19. The mobile eNB according to claim 17, wherein the silence indicator is transmitted in a licensed frequency band that is disjoint from the unlicensed frequency band.

20. The eNB according to claim 17, wherein:

the LTE network operates independently from the one or more Wi-Fi networks; and

the hardware processing circuitry is further arranged to determine an occurrence of the silence period or the active transmission period of the networks based at least partially on reception of wireless signals transmitted from one or more devices operating as part of the networks.

21. A non-transitory computer-readable storage medium that stores instructions for execution by one or more processors in an evolved NodeB (eNB) to perform operations for communicating with one or more User Equipments (UEs) on a Long Term Evolution (LTE) network operating in an unlicensed frequency band, the operations to configure the one or more processors to cause the eNB to:

transmit in the unlicensed frequency band a first LTE signal that includes a first reference signal during an active transmission period of a Wi-Fi network operating in the unlicensed frequency band;

restrict frequency spectra used for the transmission of the first LTE signal from frequency spectra used by the network during the active transmission period of the Wi-Fi network, wherein the first reference signal enables maintenance of synchronization between the eNB and the UEs at least during the active transmission period of the Wi-Fi network;

transmit a second LTE signal during a silence period of the Wi-Fi network, wherein the second LTE signal is transmitted in frequency spectra that includes at least a portion of the frequency spectra used by the Wi-Fi network during the active transmission period of the Wi-Fi network, the second LTE signal comprising a second reference signal; and

transmit a silence indicator that enables one or more of the UEs to determine an occurrence of at least one of the silence period or an active transmission period of the Wi-Fi network, the active transmission period being a time period that contains a transmission of a Wi-Fi device in the Wi-Fi network and the silence period being a time period that is free from transmission of the Wi-Fi device, the silence indicator comprising at least one of;

a time at which the at least one of the silence period or active transmission period occurs, or

an indication that the Wi-Fi network is currently in the silence period or active transmission period.

22. The non-transitory computer-readable storage medium according to claim 21, wherein the operations further configure the eNB to restrict the frequency spectra by restricting the frequency spectra to frequency gaps of the Wi-Fi network that are included in the unlicensed frequency band or selecting frequency spectra for transmission of the first LTE signal such that an LTE interference average power level caused to the frequency spectra used by the Wi-Fi network for transmission during the active transmission period of the Wi-F network is not greater than one percent of an average transmit power level of the Wi-Fi network.

23. The non-transitory computer-readable storage medium according to claim 21, wherein:

the first LTE signal is an orthogonal frequency division multiplexing (OFDM) signal comprising first resource elements (REs);

the second LTE signal is an OFDM signal comprising second REs; and

the transmission of the first reference signal includes transmission of first reference signal REs of the first LTE signal and the transmission of the second reference signal includes transmission of second reference signal REs of the second LTE signal.

24. The non-transitory computer-readable storage medium according to claim 21, wherein the silence indicator is transmitted in a licensed frequency band that is disjoint from the unlicensed frequency band.

25. A method of communicating with one or more User Equipments (UEs) on a Long Term Evolution (LTE) network operating in an unlicensed frequency band, the method comprising:

transmitting in the unlicensed frequency band a first LTE signal that includes a first reference signal during an active transmission period of a Wi-Fi network operating in the unlicensed frequency band;

restricting frequency spectra used for the transmission of the first LTE signal from frequency spectra used by the Wi-Fi network during the active transmission period of the Wi-Fi network, wherein the first reference signal enables maintenance of synchronization between the eNB and the UEs at least during the active transmission period of the Wi-Fi network;

transmitting a second LTE signal during a silence period of the Wi-Fi network, wherein the second LTE signal is transmitted in frequency spectra that includes at least a portion of the frequency spectra used by the Wi-Fi network during the active transmission period of the Wi-Fi network, the second LTE signal comprising a second reference signal; and

transmit a silence indicator that enables one or more of the UEs to determine an occurrence of at least one of the silence period or an active transmission period of the Wi-Fi network, the active transmission period being a time period that contains a transmission of a Wi-Fi device in the Wi-Fi network and the silence period being a time period that is free from transmission of the Wi-Fi device, the silence indicator comprising at least one of;

a time at which the at least one of the silence period or active transmission period occurs, or

an indication that the Wi-Fi network is currently in the silence period or active transmission period.

26. An Evolved Node-B (eNB) to operate in an unlicensed frequency band, the eNB comprising:

a transceiver; and

hardware processing circuitry in communication with the transceiver and configured to;

monitor the unlicensed frequency band for transmission activity of one or more other networks during a first chronological sub-frame of a periodic discovery transmission window comprising multiple non-overlapping contiguous sub-frames;

when transmission inactivity is detected during the first chronological sub-frame, cause the transceiver to transmit a discovery signal in the unlicensed frequency band during the first chronological sub-frame and refrain from transmission of discovery signals during each subsequent sub-frame of the periodic discovery transmission window;

when transmission activity is detected during the first chronological sub-frame, cause the transceiver to refrain from transmission of discovery signals during the first chronological sub-frame;

cause the transceiver to transmit a second LTE signal during a silence period of the Wi-Fi network, wherein the second LTE signal is transmitted in frequency spectra that includes at least a portion of the frequency spectra used by the Wi-Fi network during the active transmission period of the Wi-Fi network, the second LTE signal comprising a second reference signal; and

cause the transceiver to transmit a silence indicator that enables one or more of the UEs to determine an occurrence of at least one of the silence period or an active transmission period of the Wi-Fi network, the active transmission period being a time period that contains a transmission of a Wi-Fi device in the Wi-Fi network and the silence period being a time period that is free from transmission of the Wi-Fi device, the silence indicator comprising at least one of;

a time at which the at least one of the silence period or active transmission period occurs, or

an indication that the Wi-Fi network is currently in the silence period or active transmission period.

27. The eNB according to claim 26, the hardware processing circuitry is further configured to, when transmission activity is detected during the first chronological sub-frame:

monitor the unlicensed frequency band for transmission activity of the other networks during each subsequent sub-frame periodic discovery transmission window after the first chronological sub-frame until transmission inactivity is detected;

during each subsequent sub-frame periodic discovery transmission window in which transmission activity is detected, cause the transceiver to refrain from transmission of discovery signals;

during the sub-frame periodic discovery transmission window in which the transmission inactivity is detected, cause the transceiver to transmit a discovery signal; and

during sub-frames of the periodic discovery transmission window subsequent to the subframe in which the transmission inactivity is detected, cause the transceiver to refrain from transmission of discovery signals.

28. The eNB according to claim 27, wherein the hardware processing circuitry is further configured to cause the transceiver to refrain from transmission of discovery signals during the periodic discovery transmission window when transmission activity is detected during all sub-frames of the periodic discovery transmission window.

29. The eNB according to claim 26, wherein the first chronological sub-frame begins at a pre-defined time related to a reference time for reception of discovery signals at one or more User Equipments (UEs).

30. The eNB according to claim 26, wherein the eNB is further configured to operate in an unlicensed LTE (U-LTE) network and the discovery signal includes a primary synchronization signal (PSS) or a secondary synchronization signal (SSS).

31. The NB according to claim 26, wherein at least one of the other networks is a Wi-Fi network.