CREATION AND SIGNALLING OF UE LISTS TO SUPPORT FREQUENCY SELECTIVE REPEATER OPERATION

• US 20100120397A1
• Filed: 10/16/2009
• Published: 05/13/2010
• Est. Priority Date: 11/13/2008
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Zhang, Zhang, Kazmi, Muhammad, Baldemair, Robert, Gan, Jiansong
• Granted Patent: US 8,654,701 B2
• Time in Patent Office: Days
• US Class Current: 455/410
• CPC Class Codes: H04B 7/15535 Control of relay amplifier gain amplifier gain control in general H03G3/00; gain control reducing self - or loop interference H04B7/15578
• CPC Class Codes: H04B 7/15542 Selecting at relay station its transmit and receive resources selection of wireless resources by user or terminal H04W72/02; arrangements affording multiple use of the transmission path by two-dimensional division of the resources H04L5/0003, or by allocating sub-channels H04L5/003
• CPC Class Codes: H04B 7/1555 Selecting relay station antenna mode, e.g. selecting omnidirectional -, directional beams, selecting polarizations
• CPC Class Codes: H04B 7/2606 Arrangements for base station coverage control, e.g. by using relays in tunnels
• CPC Class Codes: H04W 16/26 Cell enhancers or enhancement, e.g. for tunnels, building shadow
• CPC Class Codes: H04W 52/46 in multi hop networks, e.g. wireless relay networks
• CPC Class Codes: H04W 84/047 using dedicated repeater stations

Abstract

A method of supporting frequency-selective repeaters (eNodeRs) in a wireless telecommunication system. A base station (eNodeB) classifies User Equipments (UEs) into two categories or lists of users: a white list containing UEs that may need the assistance of repeaters, and a black list containing UEs that do not need repeater assistance. The eNodeB transmits one of these two lists to the eNodeRs. The eNodeRs do not amplify resource blocks (RBs) scheduled for black list UEs. Each repeater may decide on its own whether to amplify signals for a non-black list UE by measuring signals from the UE and comparing them with predefined criteria.

Claims

1. A method of supporting frequency-selective repeaters in a wireless telecommunication system having a base station that serves a plurality of User Equipments (UEs) and one or more frequency-selective repeaters that amplify and forward signals between the base station and a portion of the UEs, said method comprising the steps of:

identifying by the base station, UEs for either a black list that identifies UEs for which signals are not to be amplified by a given repeater or a white list that identifies UEs for which signals are allowed to be amplified by the repeater;

sending the black list or white list from the base station to the repeater;

detecting by the repeater, an identity of a UE within the repeater'"'"'s transmission range;

determining whether the detected UE is on the black list or white list;

when the UE is on the black list, determining by the repeater that signals scheduled for the UE are not to be amplified; and

when the UE is on the white list, determining by the repeater whether to amplify signals scheduled for the UE.

2. The method according to claim 1, wherein the step of identifying UEs for the black list or white list includes placing a UE on the white list when at least one of the following criteria is met:

an uplink received signal strength level of a signal from the UE measured at the base station is less than a predefined uplink signal strength threshold;

a round trip time (RTT) of a signal from the base station to the UE and back is greater than a predefined RTT threshold;

an estimated direction of arrival (DoA) of a signal from the UE received at the base station indicates the UE is operating in a direction from the base station toward a known position of the repeater;

a downlink received signal strength level of a signal from the base station measured at the UE and reported to the base station is less than a predefined downlink signal strength threshold;

a received signal strength level of a reference signal from the repeater measured at the UE and reported to the base station is greater than a predefined signal strength threshold;

a transmit power of the UE reported to the base station is greater than a predefined power threshold; and

a power headroom of the UE reported to the base station is less than a predefined power headroom threshold, where the UE power headroom is the difference between the UE maximum output power and the UE transmitted or estimated power.

3. The method according to claim 1, wherein the step of determining by the repeater whether to amplify signals scheduled for a UE on the white list includes always amplifying signals scheduled for the UE when the UE is on the white list.

4. The method according to claim 1, wherein the step of determining by the repeater whether to amplify signals scheduled for a UE on the white list includes amplifying signals scheduled for the UE when a signal quality measurement for the UE, as measured at the repeater, exceeds a predefined threshold level.

5. The method according to claim 4, wherein the step of amplifying signals scheduled for the UE when the signal quality measurement for the UE exceeds a predefined threshold level includes amplifying signals scheduled for the UE when a received signal strength or error rate meets predefined criteria.

6. The method according to claim 1, wherein the step of determining by the repeater whether to amplify signals scheduled for a UE on the white list includes amplifying signals scheduled for the UE when a round trip time for a signal between the UE and the repeater is less than a predefined value.

7. The method according to claim 1, wherein the wireless telecommunication system includes a plurality of frequency-selective repeaters at different locations, and the method further comprises creating by the base station, a different black list or white list for each repeater.

8. The method according to claim 7, further comprising sending a report to the base station by each of the plurality of repeaters indicating the identities of either the UEs for which each repeater amplified the signals or the UEs for which each repeater did not amplify the signals.

9. The method according to claim 8, further comprising:

determining by the base station that the repeaters failed to amplify the signal associated with a white list UE; and

in response, re-classifying the white list UE as a black list UE.

10. The method according to claim 8, further comprising:

determining by the base station that the repeaters failed to amplify the signal associated with a white list UE; and

in response, instructing one of the repeaters to amplify and forward the signal associated with the white list UE.

11. A base station for supporting frequency-selective repeaters in a wireless telecommunication system, wherein the base station serves a plurality of User Equipments (UEs) and one or more frequency-selective repeater amplifies and forwards signals between the base station and a portion of the UEs, said base station comprising:

a UE classifier for identifying UEs that either require or do not require amplification by the repeater; and

an interface unit for notifying the repeater of the identified UEs.

12. The base station of claim 11, wherein the UE classifier places the UEs on either a black list that identifies UEs for which signals are not to be amplified by the repeater or a white list that identifies UEs for which signals are allowed to be amplified by the repeater, wherein the UE classifier includes means for considering at least one of the following criteria when identifying UEs for the black list or the white list:

an uplink received signal strength level of a signal from the UE measured at the base station;

a round trip time (RTT) of a signal from the base station to the UE and back;

an estimated direction of arrival (DoA) of a signal from the UE received at the base station;

a downlink received signal strength level of a signal from the base station measured at the UE and reported to the base station;

a received signal strength level of a reference signal from the repeater measured at the UE and reported to the base station;

a transmit power of the UE reported to the base station; and

a power headroom of the UE reported to the base station.

13. The base station according to claim 12, wherein the wireless telecommunication system includes a plurality of frequency-selective repeaters at different locations, and the UE classifier includes means for creating a different black list or white list for each repeater.

14. The base station according to claim 13, wherein:

the interface unit includes means for receiving a report from each of the plurality of repeaters indicating the identities of either the UEs for which each repeater amplified the signals or the UEs for which each repeater did not amplify the signals;

wherein a processor in the base station analyzes the received reports and determines whether the repeaters failed to amplify the signal for a white list UE; and

wherein in response to determining that the repeaters failed to amplify the signal for a white list UE, the processor causes the UE classifier to re-classify the white list UE as a black list UE.

15. The base station according to claim 13, wherein:

the interface unit includes means for receiving a report from each of the plurality of repeaters indicating the identities of either the UEs for which each repeater amplified the signals or the UEs for which each repeater did not amplify the signals;

wherein a processor in the base station analyzes the received reports and determines whether the repeaters failed to amplify the signal for a white list UE; and

wherein in response to determining that the repeaters failed to amplify the signal for a white list UE, the processor causes the interface unit to send an instruction to one of the repeaters to amplify and forward the signal to the white list UE.

16. A frequency-selective repeater in a wireless telecommunication system for amplifying and forwarding signals between a base station and a plurality of User Equipments (UEs) served by the base station, said repeater comprising:

an interface unit for receiving a list of UEs from the base station; and

means for amplifying and forwarding signals only to UEs identified by the received list.

17. The frequency-selective repeater according to claim 16, wherein the repeater includes:

a list analyzer for determining whether the received list is a black list that identifies UEs for which signals are not to be amplified by the repeater or a white list that identifies UEs for which signals are allowed to be amplified by the repeater; and

a UE classifier for determining which white list UEs should have their signals amplified.

18. The frequency-selective repeater according to claim 17, wherein the UE classifier determines that all white list UEs are to have their signals amplified.

19. The frequency-selective repeater according to claim 17, wherein the UE classifier includes means for determining that signals scheduled for a white list UE are to be amplified whenever a signal quality measurement for the UE, as measured at the repeater, exceeds a predefined threshold level.

20. The frequency-selective repeater according to claim 17, wherein the UE classifier includes means for determining that signals scheduled for a white list UE are to be amplified whenever a round trip time for a signal between the UE and the repeater is less than a predefined value.

21. The frequency-selective repeater according to claim 16, wherein the interface unit includes means for sending a report to the base station indicating the identities of either the UEs for which the repeater amplified the signals or the UEs for which the repeater did not amplify the signals.