DISTRIBUTED ANTENNA SYSTEM AND METHOD FOR ENHANCED POSITIONING

• US 20130336224A1
• Filed: 12/16/2011
• Published: 12/19/2013
• Est. Priority Date: 03/07/2011
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Intel Corporation
• Inventors: Davydov, Alexei, Maltsev, Alexander, Etemad, Kamran, Morozov, Gregory, Sergeyev, Vadim
• Granted Patent: US 9,402,233 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: H04B 7/2656 for structure of frame, burst
• CPC Class Codes: H04L 5/001 the frequencies being arranged in component carriers
• CPC Class Codes: H04L 5/0033 each allocating device acting autonomously, i.e. without negotiation with other allocating devices
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04W 28/0205 at the air interface dynamic wireless traffic scheduling H04W72/12
• CPC Class Codes: H04W 4/70 Services for machine-to-machine communication [M2M] or machine type communication [MTC]
• CPC Class Codes: H04W 52/0251 using monitoring of local events, e.g. events related to user activity
• CPC Class Codes: H04W 72/51 based on terminal or device properties
• CPC Class Codes: H04W 72/52 based on load
• CPC Class Codes: H04W 8/186 Processing of subscriber group data
• CPC Class Codes: H04W 88/085 Access point devices with remote components

Abstract

Embodiments of a distributed antenna system (DAS) and method for enhanced positioning in a wireless network are generally described herein. In some embodiments, an enhanced Node-B (eNB) operates as part of a DAS that includes one or more nodes having the same cell ID as the eNB. The eNB is to transmit a UE-specific reference signal and configure one or more of the other nodes of the cell to transmit UE-specific reference signals that are distinguishable from each other and from the UE-specific reference signal that is transmitted by the eNB. The eNB may receive location estimate information from user equipment (UE) that is determined at least in part from the UE-specific reference signals. The eNB may also configure the nodes to perform cooperative OFDMA transmission techniques for the UEs operating in the cell.

Claims

1. An enhanced Node-B (eNB) to operate as part of a distributed antenna system (DAS) comprising one or more nodes having a same cell ID and operating within a same cell as the eNB, the eNB arranged to:

transmit a UE-specific reference signal;

configure one or more of the other nodes of a cell to transmit UE-specific reference signals that are distinguishable from each other and from the UE-specific reference signal that is transmitted by the eNB; and

receive location estimate information from a user equipment (UE) that is determined at least in part from the UE-specific reference signals,

wherein each of the UE-specific reference signals comprise a channel state information reference signal (CSI-RS).

2. The eNB of claim 1 wherein the eNB is further arranged to transmit a cell-specific reference signal,

wherein the location estimate information from the UE is determined by the UE based on the cell-specific reference signal in addition to the UE-specific reference signals.

3. The eNB of claim 2 wherein the nodes comprise remote radio heads (RRHs), and

wherein the cell-specific reference signal is a positioning reference signal (PRS).

4. The eNB of claim 3 wherein the PRS is transmitted in a first logical portion of a wireless frame, and the CSI-RSs are transmitted in a second logical portion of the frame, and

wherein the eNB and the nodes are arranged to:

concurrently transmit data in a data portion of the wireless frame that follows the second logical portion as part of a cooperative transmission.

5. The eNB of claim 4 wherein the wireless frame is an orthogonal frequency division multiple access (OFDMA) downlink subframe,

wherein the CSI-RSs, are concurrently transmitted by the nodes and the eNB in the second logical portion, and

wherein the eNB configures the nodes to perform cooperative OFDMA transmission techniques for one or more user equipment operating in the cell.

6. The eNB of claim 3 wherein the PRS is broadcast by the eNB, and

wherein each of the CSI-RSs are transmitted in a region of a physical downlink shared channel (PDSCH).

7. The eNB of claim 3 wherein the eNB is arranged to:

transmit a first CSI-RS with a first UE-specific scrambling code; and

instruct each of the RRHs to transmit a CSI-RS with different UE-specific scrambling codes.

8. The eNB of claim 7 wherein all the CSI-RSs are transmitted within same resource elements of a resource block that is concurrently transmitted by the eNB and the RRHs.

9. The eNB of claim 7 wherein the eNB is arranged to:

transmit the first CSI-RS on a first set of resource elements; and

instruct each of the RRHs to transmit an associated CSI-RS, at least in part, on a different set of resource elements of a resource block that is concurrently transmitted by the eNB and the RRHs.

10. The eNB of claim 3 wherein the eNB is arranged to:

transmit a first CSI-RS with a cell-specific scrambling code;

instruct each of the RRHs to transmit a CSI-RS with the cell-specific scrambling code; and

wherein the eNB is arranged to;

transmit the first CSI-RS on a first set of resource elements; and

instruct each of the RRHs to transmit an associated CSI-RS, at least in part, on a different set of resource elements of a resource block that is concurrently transmitted by the eNB and the RRHs.

11. The eNB of claim 3 wherein the UE is arranged to:

perform an initial location estimate using the received PRS and a PRS received from an eNB of one or more other cells;

update the initial location estimate using the received CSI-RS from the eNB and the CSI-RSs received from the RRHs of the cell;

perform channel estimations using the CSI-RS from the eNB and the CSI-RSs from one or more of the RRHs;

report updated location estimate information to the eNB; and

provide feedback to the eNB indicative of the channel estimations for use by the eNB and the RRHs for cooperative OFDMA transmissions.

12. The eNB of claim 11 wherein the eNB is arranged to provide a location service (LCS) to the UE based on the updated location estimate information.

13. The eNB of claim 11 wherein the eNB is arranged to request one or more neighboring eNBs to apply PDSCH muting to CSI-RS subcarriers when the UE is unable to accurately update its initial location estimate using the CSI-RSs.

14. A base station to operate within a cell that includes one or more other nodes that have a same cell identifier (ID) as the base station, the base station arranged to:

transmit a UE-specific reference signal;

instruct the other nodes of the cell to transmit UE-specific reference signals that are distinguishable from each other and from the UE-specific reference signal that is transmitted by the base station;

receive a location estimate information from a mobile station that is determined at least in part from the UE-specific reference signals; and

receive feedback indicative of channel estimates from the mobile station that is determined from the UE-specific reference signals; and

use the feedback indicative of channel estimates for multiple-input multiple-output (MIMO) beamforming for configuring a cooperative transmission to the mobile station; and

use the location estimate information to provide a location-based service to the mobile station.

15. The base station of claim 14 wherein the base station is further arranged to:

transmit a cell-specific reference signal; and

receive the location estimate information from the mobile station that is determined by the mobile station based on the cell-specific reference signal as well as the UE-specific reference signals.

16. The base station of claim 15 wherein the UE-specific reference signals are channel state information reference signals (CSI-RSs), and

wherein the cell-specific reference signal is a positioning reference signal (PRS).

17. User Equipment (UE) arranged for receipt of cooperative orthogonal frequency division multiple access (OFDMA) transmissions from an enhanced Node-B (eNB) and one or more remote radio heads (RRHs) of a cell,

wherein the UE is arranged to:

receive a UE-specific reference signal from the eNB;

receive UE-specific reference signals from one or more of the RRHs that are distinguishable from each other and from the UE-specific reference signal received from the eNB; and

generate a location estimate at least in part from the UE-specific reference signals.

18. The UE of claim 17 wherein the UE is further arranged to receive a cell-specific reference signal from a current cell and a cell-specific reference signal from one or more neighbor cells, and

wherein the UE is arranged to:

determine an initial location estimate from the cell-specific reference signal; and

update the location estimate using the UE-specific reference signals.

19. The UE of claim 18 wherein each of the UE-specific reference signals, is a channel state information reference signal (CSI-RS), and

wherein the cell-specific reference signal is a positioning reference signal (PRS), and

wherein the UE is further arranged to:

perform channel estimations using the CSI-RS from the eNB and the CSI-RSs from each of the RRHs;

report an updated location estimate to the eNB; and

provide feedback to the eNB indicative of the channel estimations for use by the eNB and the RRHs for cooperative OFDMA transmissions.

20. A method performed by an enhanced Node-B (eNB) arranged to operate as part of a distributed antenna system (DAS) comprising one or more nodes having a same cell identifier (ID) and operating within a same cell as the eNB, the method comprising:

transmitting a UE-specific reference signal;

configuring one or more other nodes of the cell to transmit UE-specific reference signals that are distinguishable from each other and from the UE-specific reference signal that is transmitted by the eNB; and

receiving location estimate information from a user equipment (UE) that is determined at least in part from the UE-specific reference signals.

21. The method of claim 20 further comprising:

transmitting a cell-specific reference signal,

wherein each of the UE-specific reference signals, is a channel state information reference signal (CSI-RS), and

wherein the cell-specific reference signal is a positioning reference signal (PRS),

wherein the PRS is transmitted in a first logical portion of a wireless frame, and the CSI-RSs, are transmitted in a second logical portion of the frame,

wherein the eNB and the nodes are arranged to concurrently transmit data in a data portion of the wireless frame that follows the second logical portion as part of a cooperative transmission, and

wherein the wireless frame is an OFDMA downlink subframe.

22. The method of claim 21 wherein the CSI-RSs, are concurrently transmitted by the nodes and the eNB in the second logical portion of the wireless frame.

23. The method of claim 21 wherein the location estimate information from the UE is determined by the UE based on the cell-specific reference signal in addition to the UE-specific reference signals.