Differential randomization of cell-specific and common pilot subcarriers in multi-carrier, multi-cell wireless communication networks

• US 10,326,631 B2
• Filed: 08/28/2017
• Issued: 06/18/2019
• Est. Priority Date: 01/29/2004
• Status: Active Grant

• Current Assignee: Neo Wireless LLC (f/k/a CFIP NCF LLC) (SoftBank Group Corp.)
• Original Assignee: Neocific Incorporated
• Inventors: Li, Xiaodong, Lo, Titus, Li, Kemin, Huang, Haiming
• Primary Examiner(s): Sarwar, Babar
• Application Number:
  US15/688,441
• Publication Number:
  US 20180167251A1
• Time in Patent Office: 659 Days
• Field of Search: 4554042, 4554121-4142, 455418-4221, 455 6711- 6713, 4551151, 455423, 455436-444, 455502, 4555521, 4555621, 455434, 455525, 370324, 370332, 370319, 370344, 370350, 370329, 370338, 370328, 370203, 370280, 370342, 370335
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04J 11/005 of intercell interference
• CPC Class Codes: H04L 25/0228 with direct estimation from sounding signals
• CPC Class Codes: H04L 25/03834 using pulse shaping
• CPC Class Codes: H04L 27/0008 arrangements for allowing a transmitter or receiver to use more than one type of modulation negotiating modulation type for two-way transmission paths H04L5/1453
• CPC Class Codes: H04L 27/0012 arrangements for identifying the type of modulation
• CPC Class Codes: H04L 27/2602 Signal structure
• CPC Class Codes: H04L 27/2607 Cyclic extensions
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 27/26134 Pilot insertion in the transmitter chain, e.g. pilot overlapping with data, insertion in time or frequency domain
• CPC Class Codes: H04L 27/2637 with direct modulation of individual subcarriers
• 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 27/2655 Synchronisation arrangements
• CPC Class Codes: H04L 27/2657 Carrier synchronisation
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0016 Time-frequency-code
• CPC Class Codes: H04L 5/0028 Variable division signaling therefor H04L5/0092
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04W 16/02 Resource partitioning among network components, e.g. reuse partitioning
• CPC Class Codes: H04W 72/044 : based on the type of the allocated resource
• CPC Class Codes: H04W 72/0446 : Resources in time domain, e.g. slots or frames

Abstract

A multi-carrier cellular wireless network (400) employs base stations (404) that transmit two different groups of pilot subcarriers: (1) cell-specific pilot subcarriers, which are used by a receiver to extract information unique to each individual cell (402), and (2) common pilots subcarriers, which are designed to possess a set of characteristics common to all the base stations (404) of the system. The design criteria and transmission formats of the cell-specific and common pilot subcarriers are specified to enable a receiver to perform different system functions. The methods and processes can be extended to other systems, such as those with multiple antennas in an individual sector and those where some subcarriers bear common network/system information.

Claims

1. A mobile station in an orthogonal frequency division multiplexing (OFDM) wireless communication system comprised of a plurality of base stations in a plurality of cells, the mobile station comprising:

a receiver configured to receive a set of cell-specific pilot subcarriers from a first base station in a first cell in which the mobile station is operating, wherein the set of cell-specific pilot subcarriers were generated by a first randomization process specific to the first cell;

the receiver is further configured to receive a set of common pilot subcarriers from the first base station in the first cell and from a second base station in a second cell, wherein;

the first cell and the second cell are in a group with a common group identifier; and

the common pilot subcarriers from the first base station and the common pilot subcarriers from the second base station were generated by a second randomization process common to both the first cell and the second cell, the second randomization process randomizing the common pilot subcarriers differently than in cells having a different common group identifier; and

the receiver is further configured to apply the received set of cell-specific pilot subcarriers to determine cell-specific channel coefficients for a cell-specific channel, the cell-specific channel corresponding to a channel from the first base station to the mobile station.

2. The mobile station of claim 1, wherein the receiver is further configured to receive cell-specific data subcarriers from the first base station, the cell-specific data subcarriers carrying data information specific to the first cell.

3. The mobile station of claim 2, wherein the receiver is further configured to apply the determined cell-specific channel coefficients to the received cell-specific data subcarriers to recover the cell-specific data information.

4. The mobile station of claim 1, wherein the receiver is further configured to receive common data subcarriers from the first base station and the second base station, the common data subcarriers carrying data information common to both the first cell and the second cell.

5. The mobile station of claim 4, wherein the receiver is further configured to apply the received set of common pilot subcarriers to determine composite channel coefficients for a composite channel, the composite channel corresponding to an aggregate of different channels from first and second base stations to the mobile station.

6. The mobile station of claim 5, wherein the receiver is further configured to apply the determined composite channel coefficients to the received common data subcarriers to recover the common data information.

7. The mobile station of claim 1, wherein the second randomization process is frequency randomization.

8. A method for a mobile station in an orthogonal frequency division multiplexing (OFDM) wireless communication system comprised of a plurality of base stations in a plurality of cells, the method comprising:

receiving a set of cell-specific pilot subcarriers from a first base station in a first cell in which the mobile station is operating, wherein the set of cell-specific pilot subcarriers were generated by a first randomization process specific to the first cell;

receiving a set of common pilot subcarriers from the first base station in the first cell and from a second base station in a second cell, wherein;

the first cell and the second cell are in a group with a common group identifier; and

the common pilot subcarriers from the first base station and the common pilot subcarriers from the second base station were generated by a second randomization process common to both the first cell and the second cell, the second randomization process randomizing the common pilot subcarriers differently than in cells having a different common group identifier; and

applying the received set of cell-specific pilot subcarriers to determine cell-specific channel coefficients for a cell-specific channel, the cell-specific channel corresponding to a channel from the first base station to the mobile station.

9. The method of claim 8, further comprising receiving cell-specific data subcarriers from the first base station, the cell-specific data subcarriers carrying data information specific to the first cell.

10. The method of claim 9, further comprising applying the determined cell-specific channel coefficients to the received cell-specific data subcarriers to recover the cell-specific data information.

11. The method of claim 8, further comprising receiving common data subcarriers from the first base station and the second base station, the common data subcarriers carrying data information common to both the first cell and the second cell.

12. The method of claim 11, further comprising applying the received set of common pilot subcarriers to determine composite channel coefficients for a composite channel, the composite channel corresponding to an aggregate of different channels from first and second base stations to the mobile station.

13. The method of claim 12, further comprising applying the determined composite channel coefficients to the received common data subcarriers to recover the common data information.

14. The method of claim 8, wherein the second randomization process is frequency randomization.