Interference Control, SINR Optimization and Signaling Enhancements to Improve the Performance of OTDOA Measurements

• US 20100317343A1
• Filed: 06/10/2010
• Published: 12/16/2010
• Est. Priority Date: 06/12/2009
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Nimbalker, Aljit, Zhuang, Xiangyang, Love, Robert T., Stewart, Kenneth A., Krishnamurthy, Sandeep H.
• Granted Patent: US 9,002,354 B2
• Time in Patent Office: Days
• US Class Current: 455/435.1
• CPC Class Codes: G01S 1/30 the synchronised signals being continuous waves or intermittent trains of continuous waves, the intermittency not being for the purpose of determining direction or position line and the transit times being compared by measuring the phase difference
• CPC Class Codes: G01S 5/0236 Assistance data, e.g. base station almanac
• CPC Class Codes: G01S 5/10 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements , e.g. omega or decca systemsG01S5/12 takes precedence ; beacons and receivers cooperating therewith G01S1/306, G01S1/308
• CPC Class Codes: H04L 27/2603 Signal structure ensuring backward compatibility with legacy system
• CPC Class Codes: H04L 27/2656 Frame synchronisation, e.g. packet synchronisation, time division duplex [TDD] switching point detection or subframe synchronisation
• CPC Class Codes: H04L 43/0852 Delays
• CPC Class Codes: H04L 5/005 of common pilots, i.e. pilots destined for multiple users or terminals
• CPC Class Codes: H04L 5/0094 Indication of how sub-channels of the path are allocated
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management
• CPC Class Codes: H04W 72/044 based on the type of the allocated resource
• CPC Class Codes: Y02D 30/00 Reducing energy consumption in communication networks

Abstract

A wireless terminal receives signaling information, pertaining to a reference signal transmission in at least one specifically designated sub frame, the signaling information including a list, the list including base station identities. The terminal determines, from at least one of the base station identities in the list, the time-frequency resources associated with a reference signal transmission intended for observed time difference of arrival (OTDOA) measurements from a transmitting base station associated with said one base station identity. The time of arrival of a transmission from the transmitting base station, relative to reference timing, is measured. The wireless terminal can receive a command from a serving cell to start performing inter-frequency OTDOA measurement on a frequency layer containing reference signals, the frequency layer distinct from the serving frequency layer, the serving frequency layer not containing positioning reference signals. The wireless terminal can perform OTDOA measurements subsequent to the reception of the command on a carrier frequency different from the serving cell carrier frequency. A base station transmitter can jointly schedule a reference signal transmission from a plurality of base station transmitters for the purpose of OTD estimation enhancement, and transmit identical reference signals from the plurality of base station transmitters, the reference signals being identical both in the signal sequence and time-frequency resources used for transmission.

Claims

1. A method in a wireless terminal including

receiving signaling information, pertaining to a reference signal transmission in at least one specifically designated sub frame, the signaling information including a list, the list including base station identities;

determining, from at least one of the base station identities in the list, the time-frequency resources associated with a reference signal transmission intended for observed time difference of arrival (OTDOA) measurements from a transmitting base station associated with said one base station identity; and

measuring time of arrival of a transmission from the transmitting base station relative to a reference timing.

2. The method of claim 1 further including

receiving signaling information on reference signal patterns corresponding to a serving cell and neighbor cells.

3. The method of claim 1 further including

receiving a neighbor cell list together with the relationship between a base station identity of a neighbor cell and a measurement pattern.

4. The method of claim 1 wherein the measurement pattern follows a predetermined time-frequency re-use pattern.

5. The method of claim 1 further including

receiving frequency layer information corresponding to said serving cell base station and at least one neighbor cell base station.

6. The method of claim 1 further including

receiving a minimum measurement bandwidth associated with reference signal transmissions for the purpose of OTDOA measurements applicable to neighbor cells.

7. The method of claim 1 further including

receiving deployment type information pertaining to whether the OTDOA sub frame transmissions from a serving cell and neighbor cells are aligned, partially aligned or unsynchronized, the deployment type information directly indicating one of aligned, partially aligned, unsynchronized, or search window size.

8. The method of claim 1 further including

receiving system timing of a neighbor cell relative to a serving cell, the system timing corresponding to a system frame number time difference for each neighbor cell relative to said serving cell.

9. The method of claim 1 further including

receiving an indication to use cell-specific reference symbols (CRS) for OTDOA measurements;

and receiving information pertaining to at least one sub frame over which the wireless terminal is expected to perform neighbor cell OTDOA measurements.

10. The method of claim 1 further including

receiving subframe-subframe timing difference for neighbor cells relative to serving cell.

11. The method of claim 1 wherein the base station identity is one of at least physical cell identity (PCID) or site identity.

12. A method in a wireless terminal including

receiving a command from a serving cell to start performing inter-frequency OTDOA measurement on a frequency layer containing reference signals, the frequency layer distinct from the serving frequency layer, the serving frequency layer not containing positioning reference signals;

and

performing OTDOA measurements subsequent to the reception of the command on a carrier frequency different from the serving cell carrier frequency.

13. The method of claim 12 further including

receiving information regarding times when transmission gaps from the serving cell are enabled.

14. The method of claim 12 further including

receiving information regarding times when transmission gaps from the serving cell are disabled.

15. A method in a first wireless base station including

exchanging system timing information with a second base station;

scheduling transmission of OTDOA reference signals using the timing information, the transmission scheduled such that the transmission of OTDOA reference signals from the first and second base stations substantially overlap in time, and the OTDOA reference signals from the first and second base stations being substantially different.

16. The method of claim 15 wherein the system timing information being reference system times corresponding to the OTDOA subframes.

17. A method in a plurality of base station transmitters including

jointly scheduling a reference signal transmission from a plurality of base station transmitters for the purpose of OTD estimation enhancement;

and

transmitting identical reference signals from the plurality of base station transmitters, the reference signals being identical both in the signal sequence and time-frequency resources used for transmission.

18. The method of claim 17 wherein the time-frequency resources used for the OTDOA signal and the sequence used are established by at least one of a physical cell identity (PCID), a global cell identity (GCID), a system frame number (SFN), and sub frame index.

19. The method of claim 17 further including

subdividing a set of possible PCIDs that can be assigned to the plurality of base station transmitters into at least first and second disjoint sets, the possible PCIDs each associated with an index, and wherein the at least first and second disjoint sets comprise PCIDs allocated to transmitters that are colocated;

transmitting identical OTDOA reference signals from transmitters with PCIDs belonging to the same one of said at least first and second disjoint sets; and

signaling a mode of transmission to a mobile station.