Creation and signalling of UE lists to support frequency selective repeater operation

• US 8,654,701 B2
• Filed: 10/16/2009
• Issued: 02/18/2014
• Est. Priority Date: 11/13/2008
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Kazmi, Muhammad, Gan, Jiansong, Baldemair, Robert, Zhang, Zhang
• Primary Examiner(s): Moore, Ian N
• Assistant Examiner(s): ZUNIGA ABAD, JACKIE
• Application Number:
  US12/580,340
• Publication Number:
  US 20100120397A1
• Time in Patent Office: 1,586 Days
• Field of Search: None
• US Class Current: 370/318
• 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 Equipment (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:

receiving, at a repeater, a list transmitted by a base station, wherein the list comprises a white list that identifies a subset of a plurality of UEs served by the base station, and wherein the identified subset of UEs comprises UEs for which the repeater is allowed to amplify signals;

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

determining whether signals scheduled for the detected UE are to be amplified based on the list;

amplifying at least a portion of signals received by the repeater in accordance with the determination;

sending a report to the base station indicating an identity of a first UE identified by the white list for which the repeater did not amplify signals; and

in response to the report, receiving information from the base station instructing the repeater to re-classify the first UE for inclusion in a black list, wherein the black list identifies UEs for which the repeater is not to amplify signals.

2. The method according to claim 1, further comprising identifying, by the base station, UEs to be included in the white list and 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 determining whether signals scheduled for the detected UE are to be amplified based on the 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 determining whether signals scheduled for the detected UE are to be amplified based on the list includes amplifying signals scheduled for the UE when the UE is on the white list and 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 determining whether signals scheduled for the detected UE are to be amplified based on the list includes amplifying signals scheduled for the UE when the UE is on the white list and 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 list for each of at least two of the plurality of repeaters.

8. The method according to claim 1, wherein receiving information from the base station instructing the repeater not to amplify signals qof the first UE comprises:

receiving information instructing the repeater to re-classify the first UE for inclusion in a black list, wherein the black list identifies UEs for which the repeater is not to amplify signals.

9. A base station for supporting repeaters in a wireless telecommunication system, wherein the base station is capable of serving a plurality of User Equipment (UEs) and the repeaters are capable of amplifying and forwarding signals between the base station and a portion of the UEs, said base station comprising:

a UE classifier configured to generate a white list for a first repeater that identifies a subset of a plurality of served UEs, and wherein the identified subset of UEs comprises UEs for which the first repeater is allowed to amplify signals;

an interface unit configured to to;

notify the repeater of the identified UEs; and

receive a report from the first repeater indicating an identify of a first UE identified by the white list for which the first repeater did not amplify signals; and

a processor configured to;

analyze the received report and determine whether the first repeater failed to amplify the signal for the first UE; and

in response to determining that the first repeater failed to amplify the signal for the first UE, cause the UE classifier to re-classify the first UE for inclusion in a black list, wherein the black list identifies UEs for which the first repeater is not to amplify signals.

10. The base station of claim 9, wherein the UE classifier is further configured to place identified UEs on a list that either identifies UEs for which signals are not to be amplified by the repeater or that identifies UEs for which signals are allowed to be amplified by the repeater, wherein the UE classifier is further configured to consider at least one of the following criteria when identifying UEs for the 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.

11. The base station according to claim 10, wherein the wireless telecommunication system includes a plurality of repeaters at different locations, and the UE classifier is further configured to create a different list for each repeater.

12. A repeater for amplifying and forwarding signals between a base station and a plurality of User Equipment (UEs) served by the base station, said repeater comprising:

an interface unit configured to receive a list of UEs from the base station wherein the list comprises a white list that identifies a subset of a plurality of UEs served by the base station, and wherein the identified subset of UEs comprises UEs for which the repeater is allowed to amplify signals; and

a list analyzer and/or a UE classifier configured to determine whether or not signals scheduled for a first UE are to be amplified based on the list and to instruct an amplifier whether or not to amplify signals for the UE based on the determination;

the amplifier configured to amplify and forward signals in accordance with instructions from the list analyzer and/or the UE classifier only to UEs identified by the received list; and

a processor configured to send a report to the base station indicating an identity of a first UE identified by the white list for which the repeater did not amplify signals, wherein the interface unit is further configured to receive information from the base station instructing the repeater not to amplify signals of the first UE in response to the report, and wherein the list analyzer and/or the UE classifier is configured to re-classify the first UE for inclusion in a black list, wherein the black list identifies UEs for which the first repeater is not to amplify signals.

13. The repeater according to claim 12, wherein the repeater includes:

a list analyzer configured to determine 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 configured to determine which white list UEs should have their signals amplified.

14. The repeater according to claim 12, and wherein the UE classifier is further configured to determine that signals scheduled for a first UE are to be amplified when the first UE is included in the white list and a signal quality measurement for the UE, as measured at the repeater, exceeds a predefined threshold level.

15. The repeater according to claim 12, and wherein the UE classifier is further configured to determine that signals scheduled for a first UE are to be amplified when the first UE is included in the white list and a round trip time for a signal between the UE and the repeater is less than a predefined value.