APPARATUS AND METHOD FOR COMMUNICATING AND PROCESSING A POSITIONING REFERENCE SIGNAL BASED ON IDENTIFIER ASSOCIATED WITH A BASE STATION

• US 20100195566A1
• Filed: 02/03/2009
• Published: 08/05/2010
• Est. Priority Date: 02/03/2009
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola Mobility, Inc. (Lenovo Group Ltd.)
• Inventors: Zhuang, Xiangyang, Nimbalker, Ajit, Love, Robert T., Stewart, Kenneth A., Krishnamurthy, Sandeep H.
• Granted Patent: US 7,940,740 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04L 5/0091 Signaling for the administration of the divided path

Abstract

A base station communicates a positioning reference signal (PRS) to wireless communication devices over a downlink in a wireless communication system by encoding a PRS into a first set of transmission resources, encoding other information into a second set of transmission resources, multiplexing the two sets of resources into a subframe such that the first set of resources is multiplexed into at least a portion of a first set of orthogonal frequency division multiplexed (OFDM) symbols based on an identifier associated with the base station and the second set of resources is multiplexed into a second set of OFDM symbols, and transmitting the subframe. Upon receiving the subframe, a wireless device determines which set of transmission resources contains the PRS based on the identifier associated with the base station that transmitted the subframe and processes the set of resources containing the PRS to estimate timing (e.g., time of arrival) information.

Claims

1. A wireless communication device operable in a wireless communication system that includes at least one base station, the wireless communication device comprising:

a receiver operable to receive at least a section of a subframe from a base station, the subframe including a plurality of transmission resources multiplexed onto subcarriers of a plurality of orthogonal frequency division multiplexed (OFDM) symbols, each transmission resource of the plurality of transmission resources occupying a predetermined amount of time on a respective one of the subcarriers, the plurality of OFDM symbols being arranged into at least a first set of OFDM symbols that includes a positioning reference signal and a second set of OFDM symbols that does not include the positioning reference signal; and

a processor operably coupled to the receiver, the processor operable to;

determine, based on an identifier associated with the base station, a set of transmission resources over which the positioning reference signal was transmitted, the set of transmission resources constituting at least a portion of the first set of OFDM symbols; and

process the set of transmission resources to estimate timing information associated with the positioning reference signal.

2. The wireless communication device of claim 1, wherein the processor is further operable to:

determine a time of arrival of the positioning reference signal based on reference timing information and the estimated timing information.

3. The wireless communication device of claim 2, wherein the receiver is operable to receive transmissions from a plurality of base stations, the wireless communication device further comprising:

a transmitter operably coupled to the processor and operable to communicate at least the time of arrival to at least one of the plurality of base stations.

4. The wireless communication device of claim 1, wherein the subframe forms part of a radio frame and wherein the processor is further operable to:

determine, based on the identifier, whether the subframe includes transmission resources corresponding to the positioning reference signal prior to determining the set of transmission resources.

5. The wireless communication device of claim 1, wherein a cyclic prefix associated with each OFDM symbol in the portion of the first set of OFDM symbols is identical.

6. The wireless communication device of claim 1, wherein the first set of OFDM symbols includes at least a first subset of OFDM symbols and a second subset of OFDM symbols, wherein the set of transmission resources form the first subset of OFDM symbols, and wherein a duration of each OFDM symbol of the first subset of OFDM symbols is greater than a duration of each OFDM symbol of the second set of OFDM symbols.

7. The wireless communication device of claim 6, wherein a cyclic prefix associated with each OFDM symbol of the first subset of OFDM symbols is greater than 16.67 microseconds.

8. The wireless communication device of claim 1, wherein the identifier is derived from at least one of an offset identifier, a cell site identifier, a physical cell identifier, a global cell identifier, a symbol index, a slot index, a subframe index, a system frame number, and a radio network transaction identifier.

9. The wireless communication device of claim 8, wherein the identifier associated with the base station is identical to identifiers associated with a plurality of other base stations.

10. The wireless communication device of claim 9, wherein the base station and the plurality of other base stations are co-located.

11-21. -21. (canceled)

22. A method for a wireless communication device to at least determine position-related timing information, the wireless communication device operating in a wireless communication system that includes a plurality of base stations, the method comprising:

receiving at least a section of a subframe transmitted by a first base station of the plurality of base stations, the subframe including a plurality of transmission resources multiplexed onto subcarriers of a plurality of orthogonal frequency division multiplexed (OFDM) symbols, each transmission resource of the plurality of transmission resources occupying a predetermined amount of time on a respective one of the subcarriers, the plurality of OFDM symbols being arranged into a first set of OFDM symbols that includes a positioning reference signal and a second set of OFDM symbols that does not include a positioning reference signal;

determining, based on an identifier associated with the first base station, a set of transmission resources over which the positioning reference signal was transmitted, the set of transmission resources constituting a portion of the first set of OFDM symbols; and

processing the set of transmission resources to estimate timing information associated with the positioning reference signal.

23. The method of claim 22, further comprising:

determining a time of arrival of the positioning reference signal based on reference timing information and the estimated timing information.

24. The method of claim 23, further comprising:

communicating at least the time of arrival to at least one of the plurality of base stations.

25. The method of claim 22, wherein each of the plurality of base stations provides wireless communication service within a respective service coverage area, the method further comprising:

receiving the identifier from a second base station prior to receipt of the subframe from the first base station.

26. The method of claim 25, wherein receiving the identifier comprises:

receiving a list of identifiers associated at least some of the plurality of base stations.

27. The wireless communication device of claim 25, wherein receiving the identifier comprises:

receiving the identifier in a broadcast message from the second base station.

28. (canceled)

29. A method for a wireless communication device to determine time of arrival information from which a location of the wireless communication device may be estimated, the wireless communication device operating in a wireless communication system that includes a plurality of base stations and a location server, each of the plurality of base stations providing wireless communication service within a respective service coverage area, the location server being operable to determine locations of wireless communication devices within a coverage area of the wireless communication system, the wireless communication device receiving wireless communication service from a first base station of the plurality of base stations, the method comprising:

receiving a first subframe transmitted by a second base station of the plurality of base stations, the first subframe including a first plurality of resource elements that are divided in time across a first plurality of subcarriers to form a first plurality of orthogonal frequency division multiplexed (OFDM) symbols, each resource element of the first plurality of resource elements occupying a predetermined amount of time on a respective one of the first plurality of subcarriers, the first plurality of OFDM symbols being arranged into a first set of OFDM symbols that includes a first positioning reference signal and a second set of OFDM symbols that does not include the first positioning reference signal;

receiving a second subframe transmitted by a third base station of the plurality of base stations, the second subframe including a second plurality of resource elements that are divided in time across a second plurality of subcarriers to form a second plurality of orthogonal frequency division multiplexed (OFDM) symbols, each resource element of the second plurality of resource elements occupying a predetermined amount of time on a respective one of the second plurality of subcarriers, the second plurality of OFDM symbols being arranged into a third set of OFDM symbols that includes a second positioning reference signal and a fourth set of OFDM symbols that does not include the second positioning reference signal;

determining, based on an identifier associated with the second base station, a first set of resource elements over which the first positioning reference signal was transmitted in the first subframe, the first set of resource elements constituting a portion of the first set of OFDM symbols;

determining, based on an identifier associated with the third base station, a second set of resource elements over which the second positioning reference signal was transmitted in the second subframe, the second set of resource elements constituting a portion of the third set of OFDM symbols, wherein the portion of the third set of OFDM symbols containing the second positioning reference signal is different than and orthogonal to the portion of the first set of OFDM symbols containing the first positioning reference signal;

processing the first set of resource elements to estimate a first time of arrival of the first positioning reference signal based on a local oscillator frequency of the wireless communication device;

processing the second set of resource elements to estimate a second time of arrival of the second positioning reference signal based on the local oscillator frequency; and

communicating the first time of arrival and the second time of arrival to the location server via the first base station.

30. A method for a wireless communication device to at least determine position-related timing information, the wireless communication device operating in a wireless communication system that includes a plurality of base stations, the method comprising:

receiving at least a section of a subframe transmitted by a first base station of the plurality of base stations, the subframe including a plurality of transmission resources multiplexed onto subcarriers of a plurality of orthogonal frequency division multiplexed symbols, each transmission resource of the plurality of transmission resources occupying a predetermined amount of time on a respective one of the subcarriers, the plurality of transmission resources being arranged into at least a first set of transmission resources that includes a positioning reference signal and a second set of transmission resources that includes channel-coded data, the second set of transmission resources being different than the first set of transmission resources;

determining, based on an identifier associated with the first base station, the first set of transmission resources over which the positioning reference signal was transmitted;

determining the second set of transmission resources over which the channel-coded data was transmitted;

processing the first set of transmission resources to estimate timing information associated with the positioning reference signal; and

processing the second set of transmission resources to recover the channel-coded data.

31. The method of claim 30, wherein the plurality of transmission resources includes a third set of transmission resources over which at least one of control information, synchronization information, and one or more additional reference signals was transmitted, the third set of transmission resources being different than the first set of transmission resources and the second set of transmission resources, the method further comprising:

determining the third set of transmission resources over which at least one of control information, synchronization information, and one or more additional reference signals was transmitted; and

processing the third set of transmission resources to recover the at least one of control information, synchronization information, and one or more additional reference signals.

32. The method of claim 31, wherein the at least one of control information, synchronization information, and one or more additional reference signals includes at least one of a physical downlink control channel (PDDCH), a physical control format indicator channel (PCFICH), a physical hybrid automatic repeat request indicator channel (PHICH), a broadcast channel, a synchronization channel, a cell-specific reference signal, and a user equipment (UE) specific reference signal.

33. The method of claim 30, wherein the identifier is derived from at least one of an offset identifier, a cell site identifier, a physical cell identifier, a global cell identifier, a symbol index, a slot index, a subframe index, a system frame number, and a radio network transaction identifier.

34. The method of claim 33, wherein the offset identifier is used to derive a starting point offset for extracting a subsequence of a reference quadrature phase shift keying (QPSK) sequence.

35. A wireless communication device operable in a wireless communication system that includes at least one base station, the wireless communication device comprising:

a receiver operable to receive at least a section of a subframe from a base station, the subframe including a plurality of transmission resources multiplexed onto subcarriers of a plurality of orthogonal frequency division multiplexed (OFDM) symbols, each transmission resource of the plurality of transmission resources occupying a predetermined amount of time on a respective one of the subcarriers, the plurality of transmission resources being arranged into at least a first set of transmission resources that includes a positioning reference signal and a second set of transmission resources that includes channel-coded data, the second set of transmission resources being different than the first set of transmission resources; and

a processor operably coupled to the receiver, the processor operable to;

determine, based on an identifier associated with the base station, the first set of transmission resources over which the positioning reference signal was transmitted;

determining the second set of transmission resources over which the channel-coded data was transmitted;

process the set of transmission resources to estimate timing information associated with the positioning reference signal; and

process the second set of transmission resources to recover the channel-coded data.

36. The wireless communication device of claim 35, wherein the plurality of transmission resources includes a third set of transmission resources over which at least one of control information, synchronization information, and one or more additional reference signals was transmitted, the third set of transmission resources being different than the first set of transmission resources and the second set of transmission resources, and wherein the processor is further operable to:

determine the third set of transmission resources over which the at least one of control information, synchronization information, and one or more additional reference signals was transmitted; and

process the third set of transmission resources to recover the at least one of control information, synchronization information, and one or more additional reference signals.

37. The wireless communication device of claim 36, wherein the at least one of control information, synchronization information, and one or more additional reference signals includes at least one of a physical downlink control channel (PDDCH), a physical control format indicator channel (PCFICH), a physical hybrid automatic repeat request indicator channel (PHICH), a broadcast channel, a synchronization channel, a cell-specific reference signal, and a user equipment (UE) specific reference signal.

38. The wireless communication device of claim 35, wherein the identifier is derived from at least one of an offset identifier, a cell site identifier, a physical cell identifier, a global cell identifier, a symbol index, a slot index, a subframe index, a system frame number, and a radio network transaction identifier.

39. The wireless communication device of claim 38, wherein the offset identifier is used to derive a starting point offset for extracting a subsequence of a reference quadrature phase shift keying (QPSK) sequence.