User equipment and methods for handover enhancement using reference signal received quality (RSRQ)

• US 9,130,688 B2
• Filed: 09/28/2012
• Issued: 09/08/2015
• Est. Priority Date: 05/11/2012
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Intel Corporation
• Inventors: Yiu, Candy, Zhang, Yujian, Fong, Mo-Han, Peng, Yuefeng
• Primary Examiner(s): SHARMA, SUJATHA R
• Application Number:
  US13/631,213
• Publication Number:
  US 20130303231A1
• Time in Patent Office: 1,075 Days
• Field of Search: 455436-444, 370331-334
• US Class Current: 1/1
• CPC Class Codes: H04B 1/56 with provision for simultaneous communication in two directions
• CPC Class Codes: H04B 15/00 Suppression or limitation of noise or interference by means associated with receiver H04B1/10
• CPC Class Codes: H04B 7/024 Co-operative use of antennas of several sites, e.g. in co-ordinated multipoint or co-operative multiple-input multiple-output [MIMO] systems
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0456 Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
• CPC Class Codes: H04B 7/0473 taking constraints in layer or codeword to antenna mapping into account
• CPC Class Codes: H04B 7/0486 taking channel rank into account
• CPC Class Codes: H04B 7/0626 Channel coefficients, e.g. channel state information [CSI]
• CPC Class Codes: H04B 7/063 Parameters other than those covered in groups H04B7/0623 - H04B7/0634, e.g. channel matrix rank or transmit mode selection
• CPC Class Codes: H04B 7/0632 Channel quality parameters, e.g. channel quality indicator [CQI]
• CPC Class Codes: H04B 7/0639 Using selective indices, e.g. of a codebook, e.g. pre-distortion matrix index [PMI] or for beam selection
• CPC Class Codes: H04B 7/0647 Variable feedback rate
• CPC Class Codes: H04B 7/065 Variable contents, e.g. long-term or short-short
• CPC Class Codes: H04B 7/26 at least one of which is mobile
• CPC Class Codes: H04J 3/00 Time-division multiplex systems H04J14/00 takes precedence; relay systems H04B7/14; selecting techniques H04Q
• CPC Class Codes: H04J 3/1694 Allocation of channels in TDM/TDMA networks, e.g. distributed multiplexers Passive Optical Networks H04Q11/0062
• CPC Class Codes: H04J 3/26 in which the information and the address are simultaneously transmitted
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/1803 Stop-and-wait protocols
• CPC Class Codes: H04L 1/1822 involving configuration of automatic repeat request [ARQ] with parallel processes
• CPC Class Codes: H04L 27/2627 : Modulators
• CPC Class Codes: H04L 5/0007 : the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/001 : the frequencies being arranged in component carriers
• CPC Class Codes: H04L 5/0035 : Resource allocation in a cooperative multipoint environment
• CPC Class Codes: H04L 5/0053 : Allocation of signaling, i.e. of overhead other than pilot signals
• 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 5/0096 : Indication of changes in 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 65/00 : Network arrangements, protocols or services for supporting real-time applications in data packet communication real-time or near real-time messaging, e.g. instant messaging [IM] H04L51/04; selective video distribution H04N21/00
• CPC Class Codes: H04L 69/22 : Parsing or analysis of headers
• CPC Class Codes: H04L 69/324 : in the data link layer [OSI layer 2], e.g. HDLC
• CPC Class Codes: H04W 16/14 : Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 24/02 : Arrangements for optimising operational condition
• CPC Class Codes: H04W 24/10 : Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 36/00 : Hand-off or reselection arrangements
• CPC Class Codes: H04W 36/0058 : Transmission of hand-off measurement information, e.g. measurement reports
• CPC Class Codes: H04W 36/0061 : of neighbour cell information
• CPC Class Codes: H04W 36/0088 : Scheduling hand-off measurements
• CPC Class Codes: H04W 36/0094 : Definition of hand-off measurement parameters
• CPC Class Codes: H04W 36/04 : Reselecting a cell layer in multi-layered cells
• CPC Class Codes: H04W 36/16 : Performing reselection for specific purposes
• CPC Class Codes: H04W 36/22 : for handling the traffic
• CPC Class Codes: H04W 4/02 : Services making use of location information
• CPC Class Codes: H04W 4/023 : using mutual or relative location information between multiple location based services [LBS] targets or of distance thresholds
• CPC Class Codes: H04W 4/06 : Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services
• CPC Class Codes: H04W 4/16 : Communication-related supplementary services, e.g. call-transfer or call-hold
• CPC Class Codes: H04W 4/70 : Services for machine-to-machine communication [M2M] or machine type communication [MTC]
• CPC Class Codes: H04W 4/90 : Services for handling of emergency or hazardous situations, e.g. earthquake and tsunami warning systems [ETWS]
• CPC Class Codes: H04W 48/20 : Selecting an access point
• CPC Class Codes: H04W 52/0209 : in terminal devices terminal devices per se H04W88/02
• CPC Class Codes: H04W 52/0212 : managed by the network, e.g. network or access point is master and terminal is slave
• CPC Class Codes: H04W 52/0216 : using a pre-established activity schedule, e.g. traffic indication frame
• CPC Class Codes: H04W 52/0225 : using monitoring of external events, e.g. the presence of a signal
• CPC Class Codes: H04W 52/0229 : where the received signal is a wanted signal
• CPC Class Codes: H04W 52/0235 : where the received signal is a power saving command
• CPC Class Codes: H04W 52/0251 : using monitoring of local events, e.g. events related to user activity
• CPC Class Codes: H04W 56/00 : Synchronisation arrangements
• CPC Class Codes: H04W 56/001 : Synchronization between nodes
• CPC Class Codes: H04W 72/02 : Selection of wireless resources by user or terminal
• CPC Class Codes: H04W 72/044 : based on the type of the allocated resource
• CPC Class Codes: H04W 72/12 : Wireless traffic scheduling
• CPC Class Codes: H04W 72/1215 : for collaboration of different radio technologies
• 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 72/27 : between access points
• CPC Class Codes: H04W 72/30 : Resource management for broadcast services
• CPC Class Codes: H04W 72/51 : based on terminal or device properties
• CPC Class Codes: H04W 72/54 : based on quality criteria
• CPC Class Codes: H04W 72/541 : using the level of interference
• CPC Class Codes: H04W 72/542 : using measured or perceived quality
• CPC Class Codes: H04W 72/56 : based on priority criteria
• CPC Class Codes: H04W 76/14 : Direct-mode setup
• CPC Class Codes: H04W 76/18 : Management of setup rejection or failure
• 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 88/02 : Terminal devices
• 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 88/08 : Access point devices
• CPC Class Codes: Y02D 30/70 : in wireless communication networks

Abstract

Embodiments of user equipment (UE) and method for handover enhancement using reference signal received quality (RSRQ) in a wireless network are generally described herein. In some embodiments, a UE adaptively selects handover initiation parameters based, at least in part, on a velocity of the UE. The UE may determine an RSRQ of a serving cell and an RSRQ of a target cell and may transmit a measurement report to a serving eNB for handover from the serving cell to the target cell when the target cell RSRQ exceeds the serving cell RSRQ in accordance with the selected handover initiation parameters. In some of these embodiments, the handover initiation parameters may include an offset value, such as an A3offset value, and a time-to-trigger (TTT) that comprise an A3offset-TTT pair.

Claims

1. A method performed by user equipment (UE) for handover initiation, the method comprising:

selecting an A3offset-TTT pair based on a velocity of the UE, the A3offset-TTT pair comprising an A3offset value and a time-to-trigger (TTT);

determining a reference signal received quality (RSRQ) of a serving cell and an RSRQ of a target cell; and

transmitting a measurement report to an enhanced Node B (eNB) of the serving cell for handover to the target cell when the RSRQ of the target cell exceeds RSRQ of the serving cell by at least the A3offset value for the TTT.

2. The method of claim 1 wherein the RSRQ of the serving cell and the RSRQ of the target cell are determined from a ratio of a reference signal received power (RSRP) to a received signal strength indicator (RSSI) for resource blocks (RBs) containing reference signals.

3. The method of claim 2 wherein the RSRQ of the serving cell and the RSRQ of the target cell are determined in accordance with a 3GPP standard for E-UTRAN LTE, and

wherein the RSRQ of the serving cell and the RSRQ of the target cell are to determine an entering condition and an exiting condition for an Event-A3 for handover initiation.

4. The method of claim 3 wherein the RSRP is determined from one or more of channel state information reference signals (CIS-RS) and common reference signals (CRS) that are transmitted by an eNB in predetermined physical resource blocks (PRBs).

5. The method of claim 4 wherein for greater UE velocities, a smaller A3offset value and a shorter TTT are selected, and

wherein for lesser UE velocities, a greater A3offset value and a longer TTT are selected.

6. The method of claim 4 wherein the velocity of the UE is based on a mobility state of the UE and is determined from a number of cell reselections during a predetermined time period.

7. The method of claim 4 wherein the velocity of the UE is determined from changes in position or location estimates determined from signals transmitted from one or more eNBs including a target eNB and a serving eNB.

8. The method of claim 4 wherein the velocity of the UE is determined using an assisted satellite-positioning technique.

9. The method of claim 4 wherein for a velocity below a predetermined low value, the UE is to select a first A3offset-TTT pair from a plurality of A3offset-TTT pairs,

wherein for a velocity greater than or equal to the predetermined low value and less than or equal to a predetermined high value, the UE is to select a second A3offset-TTT pair from the plurality of A3offset-TTT pairs, and

wherein for a velocity above the predetermined high value, the UE is to select a third A3offset-TTT pair from the plurality of A3offset-TTT pairs.

10. The method of claim 2 further comprising selecting the A3offset-TTT pair based further on one or more of a serving cell type and a target cell type, the serving cell type comprising either a macro cell or a pico cell, the target cell type comprising either a macro cell or a pico cell.

11. The method of claim 10 wherein the UE is configured to determine at least one of the serving cell type and the target cell type based on one or more of cell or eNB identification information transmitted by the eNB of the serving cell and the eNB of the target cell, the identification information indicative of a macro cell or a pico cell.

12. The method of claim 10 wherein the UE is configured to determine at least one of the serving cell type and the target cell type based on measured signal strength of reference signals transmitted by at least one of the eNB of the serving cell and the eNB of the target cell.

13. The method of claim 10 wherein for a handover from a pico serving cell to a macro target cell, a smaller A3offset value and a smaller TTT are selected, and

wherein for a handover from a macro serving cell to a pico target cell, a larger A3offset value and a smaller TTT are selected.

14. User equipment (UE) comprising:

processing circuitry to select a A3offset-TTT pair based on a velocity of the UE and to determine a reference signal received quality (RSRQ) of a serving cell and an RSRQ of a target cell from a ratio of a reference signal received power (RSRP) to a received signal strength indicator (RSSI) for resource blocks (RBs) containing reference signals; and

physical layer circuitry to transmit a measurement report to a serving eNB for handover from the serving cell to the target cell when the target cell RSRQ exceeds the serving cell RSRQ by at least an A3offset value for a time-to-trigger (TTT).

15. The UE of claim 14 wherein the RSRP is determined from one or more of channel state information reference signals (CIS-RS) and common reference signals (CRS) that are transmitted by an eNB in predetermined physical resource blocks (PRBs).

16. The UE of claim 14 wherein for greater UE velocities, a smaller A3offset value and a shorter TTT are selected, and

wherein for lesser UE velocities, a greater A3offset value and a longer TTT are selected.

17. The UE of claim 14 wherein the velocity of the UE is based on a mobility state of the UE and is determined from a number of cell reselections during a predetermined time period.

18. The UE of claim 14 wherein the velocity of the UE is determined from changes in position or location estimates determined from signals transmitted from one or more eNBs including a target eNB and the serving eNB.

19. The UE of claim 14 wherein the velocity of the UE is determined using an assisted satellite-positioning technique.

20. The UE of claim 14 wherein the processing circuitry is further arranged to select the A3offset-TTT pair based further on one or more of a serving cell type and a target cell type, the serving cell type comprising either a macro cell or a pico cell, the target cell type comprising either a macro cell or a pico cell.

21. A method performed by user equipment (UE) for adaptively selecting an A3offset-TTT pair for handover initiation, the method comprising:

selecting an A3offset value based on one of reference signal received quality (RSRQ) of a target cell or reference signal received power (RSRP) of the target cell;

selecting a time-to-trigger (TTT) based on RSRQ of a serving cell; and

transmitting a measurement report to an enhanced Node B (eNB) of the serving cell for handover initiation to the target cell when the RSRQ of the target cell exceeds the RSRQ of the serving cell by at least the A3offset value for the TTT.

22. The method of claim 21 wherein the RSRQ is determined from a ratio of RSRP to a received signal strength indicator (RSSI) for resource blocks (RBs) containing reference signals.

23. The method of claim 22 wherein selecting the A3offset value comprises selecting one of a plurality of A3offset values based on the RSRQ of the target cell and one or more RSRQ thresholds or based on the RSRP of the target cell and one or more RSRP thresholds, and

wherein selecting the TTT comprises selecting one of a plurality of TTTs based on the RSRQ of the serving cell and the one or more RSRQ thresholds.

24. The method of claim 23 wherein the A3offset value is selected to be inversely related to the RSRQ or RSRP of the target cell and the TTT is selected to be directly related to the RSRQ of the serving cell.

25. A non-transitory computer-readable storage medium that stores instructions for execution by one or more processors to perform operations for handover initiation, the instructions to configure the one or more processors to:

select an A3offset-TTT pair based on a velocity of user equipment (UE), the A3offset-TTT pair comprising an A3offset value and a time-to-trigger (TTT);

determine a reference signal received quality (RSRQ) of a serving cell and an RSRQ of a target cell; and

cause transmission of a measurement report to an enhanced Node B (eNB) of the serving cell for handover to the target cell when the RSRQ of the target cell exceeds RSRQ of the serving cell by at least the A3offset value for the TTT.

26. The non-transitory computer-readable storage medium of claim 25 wherein the RSRQ of the serving cell and the RSRQ of the target cell are determined from a ratio of a reference signal received power (RSRP) to a received signal strength indicator (RSSI) for resource blocks (RBs) containing reference signal,

wherein the RSRQ of the serving cell and the RSRQ of the target cell are to determine an entering condition and an exiting condition for an Event-A3 for handover initiation, and

wherein the RSRP is determined from one or more of channel state information reference signals (CIS-RS) and common reference signals (CRS) that are transmitted by an eNB in predetermined physical resource blocks (PRBs).