Transmitter Time Adjustments for Groups of Receivers

• US 20150263878A1
• Filed: 05/15/2015
• Published: 09/17/2015
• Est. Priority Date: 12/27/2006
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Smith, Adrian, Li, Xiao-Dong, Steer, David, Au, Kelvin Kar-Kin, Novak, Robert, Earnshaw, Mark
• Granted Patent: US 10,298,433 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04B 7/18534 for enhancing link reliablility, e.g. satellites diversity
• CPC Class Codes: H04L 27/2646 using feedback from receiver for adjusting OFDM transmission parameters, e.g. transmission timing or guard interval length
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/023 Multiplexing of multicarrier modulation signals multicarrier modulation H04L27/2601
• CPC Class Codes: H04W 56/0045 compensating for timing error by altering transmission time

Abstract

A method and system for achieving a link budget improvement in a diverse OFDM radio system by addressing the timing misalignment issue that can occur due to the differences in propagation time in signals between mobile stations and Radio Access Nodes. Timing misalignment is shared or split between the primary path to a primary Radio Access Node and a diverse path to a diverse Radio Access Node. The relative timing offsets between mobile stations are adjusted, the mobile stations are grouped into zones using a variety of different grouping techniques, and the transmission for each mobile station is scheduled, using one or more of a variety of scheduling techniques.

Claims

1-20. -20. (canceled)

21. A method for operating a base station, the method comprising:

determining arrival times representative of first transmissions from a plurality of transmitters to a plurality of receivers;

for a group of two or more of the receivers, determining one or more time adjustments respectively for one or more of the transmitters based at least in part on a subset of the arrival times corresponding to one or more transmitters and the group of two or more receivers;

providing the one or more time adjustments for the group to the one or more respective transmitters for use in generating second transmissions.

22. The method of claim 21, wherein the transmitters and receivers are configured to communicate using OFDM.

23. The method of claim 21, wherein each of the receivers is communicatively coupled to the base station.

24. The method of claim 21, wherein each of the transmitters is included as part of a respective user equipment (UE) device.

25. The method of claim 21, further comprising:

dynamically updating the one or more time adjustments by repeating a set of operations including said determining the arrival times, said determining the one or more time adjustments, and said providing, wherein said dynamically updating enables synchronization of the second transmissions to be maintained in spite of movements in the one or more transmitters.

26. The method of claim 21, further comprising:

performing a process of ranging the transmitters with respect to a first of the receivers of said group prior to said determining the arrival times.

27. The method of claim 21, wherein the one or more time adjustments are one or more adjustments to timing of the first transmissions that would make arrival times at each receiver of the group fall within a cyclic prefix duration.

28. A base station comprising:

circuitry configured to;

determine arrival times representative of first transmissions from a plurality of transmitters to a plurality of receivers;

for a group of two or more of the receivers, determine one or more time adjustments respectively for one or more of the transmitters based at least in part on a subset of the arrival times corresponding to one or more transmitters and the group of two or more receivers;

provide the one or more time adjustments for the group to the one or more respective transmitters for use in generating second transmissions.

29. The base station of claim 28, wherein the transmitters and receivers are configured to communicate using OFDM.

30. The base station of claim 28, wherein the base station is communicatively coupled to each of the receivers.

31. The base station of claim 28, wherein each of the transmitters is included as part of a respective user equipment (UE) device.

32. The base station of claim 28, wherein the circuitry is further configured to:

dynamically update the one or more time adjustments by repeating a set of operations including said determining the arrival times, said determining the one or more time adjustments, and said providing, wherein said dynamically updating enables synchronization of the second transmissions to be maintained in spite of movements in the one or more transmitters.

33. The base station of claim 28, wherein the circuitry is further configured to:

perform a process of ranging the transmitters with respect to a first of the receivers of the group prior to said determining the arrival times.

34. The base station of claim 28, wherein the one or more time adjustments are one or more adjustments to timing of the first transmissions that would make arrival times at each receiver of the group fall within a cyclic prefix duration.

35. A method for operating a base station, the method comprising:

determining arrival times representative of first transmissions from a plurality of transmitters to a plurality of receivers;

for a given one of the transmitters, determining time adjustments for respective groups of the receivers, wherein said determining the time adjustments is based at least in part on a subset of the arrival times corresponding to the given transmitter and the respective groups of the receivers, wherein each of the groups includes at least one of the receivers;

providing the time adjustments to the given transmitter for use in generating second transmissions.

36. The method of claim 35, wherein the transmitters and receivers are configured to communicate using OFDM.

37. The method of claim 35, wherein each of the transmitters is included as part of a respective user equipment (UE) device.

38. The method of claim 35, further comprising:

dynamically updating the time adjustments by repeating a set of operations including said determining the arrival times, said determining the time adjustments, and said providing, wherein said dynamically updating enables synchronization of the second transmissions to be maintained in spite of movements of the given transmitter.

39. The method of claim 35, further comprising:

performing a process of ranging the transmitters with respect to a first of the receivers prior to said determining the arrival times.

40. The method of claim 35, wherein the time adjustments are adjustments to timing of the first transmissions that would make arrival times at each receiver of at least one of the groups fall within a cyclic prefix duration.