WO2013184047A1

WO2013184047A1 - Resource allocation in a communication system with sub-band repeaters

Info

Publication number: WO2013184047A1
Application number: PCT/SE2012/050592
Authority: WO
Inventors: Magnus FINNE
Original assignee: Telefonaktiebolaget L M Ericsson (Publ)
Priority date: 2012-06-04
Filing date: 2012-06-04
Publication date: 2013-12-12

Abstract

The disclosure describes a method 10 performed in a base station node 2 of a communication system 1. The communication system comprises a repeater 3 configured to receive and retransmit signaling between the base station node 2 and a wireless device 4. The repeater 3 is configured to operate on a sub-band of a frequency band on which the base station node 2 is configured to operate. The method 10 comprises: detecting 11 that the wireless device 4 transmits via the repeater 3, and scheduling 12 the wireless device 4 only on the sub-band of the repeater 3.

Description

Resource allocation in a communication system with sub-band repeaters

Technical field

The technology disclosed herein relates generally to the field of wireless communication systems, and in particular to interference reduction within such wireless communication systems.

Background

A user of a wireless device expects a strong and reliable

connection, i.e. a reliable wireless link, when communicating in a wireless communication system. There are various circumstances affecting the wireless link, such as the number of served users in the same area, the distance between the user and a serving base station, the particular landscape in which the user is located, e.g. whether there are many obstacles such as mountains or buildings that limit the coverage of the base station, to mention a few examples. Users close to a cell edge often experience low signal levels and also high interference levels. Further, such cell-edge users also contribute to uplink interference for users in other cells.

There are different ways and attempts to ensure the reliable connection. For example, a repeater may be used, which is a device that receives signals from the wireless device and retransmits the signals to the base station, typically with a higher power (uplink) , and vice versa for a downlink. Repeaters can improve signal quality, particularly for cell-edge users, but also introduces interference towards other cells. Another device that may be used for enhancing signal levels is a relay, which is more advanced than the repeater. The relay may receive, demodulate and decode the data, apply any error correction, etc. and then re-transmit a new signal. Presently discussed relays, e.g. in Long Term Evolution (LTE) are advanced, complex and costly, for example requiring advanced software, hardware and communication set-ups .

Another aspect affecting the wireless link between the user device and the base station node is the level of interference within the communication system. The interference may be combatted in various ways, for example by using Inter-cell Interference Coordination (ICIC), directed antennas, by efforts to reduce transmission power etc. A repeater, which as mentioned retransmits a signal at a higher power level, may introduce interference within the communication system, e.g. by amplifying interference and noise together with the desired signal component. Such drawbacks with repeaters may, at least to some extent, be overcome e.g. by the use of relays instead, having advanced algorithms, but then at the expense of increased costs . The rapidly increasing amount of traffic within wireless

communication systems requires continued development of interference reducing or restricting methods and devices.

Summary

An object of the present disclosure is to overcome or at least alleviate one or more of the above mentioned problems.

The object is, according to a first aspect, achieved by a method performed in a base station node of a communication system. The communication system further comprises a repeater configured to receive and retransmit signaling between the base station node and a wireless device. The repeater is configured to operate on a sub-band of a frequency band on which the base station node is configured to operate. The method comprises: detecting that the wireless device transmits via the repeater; and scheduling the wireless device only on the sub-band of the repeater. The method enables the provision of an increased coverage without increasing the interference within the communication system. The sub-band repeaters increase the coverage since signaling

retransmitted by the sub-band repeaters reaches wireless devices located farther away from the base station node. By detecting that a wireless device is transmitting via one of the sub-band repeaters, and subsequently scheduling the wireless device only on the

particular sub-band of the repeater, the interference is reduced. In particular inter-cell interference can be minimized. The use of cost-efficient low complexity repeaters is enabled, without the increased interference level that is common with prior art use of repeaters .

The object is, according to a second aspect, achieved by a base station node of a communication system. The communication system comprises a repeater configured to receive and retransmit signaling between the base station node and a wireless device. The repeater is configured to operate on a sub-band of a frequency band on which the base station node is configured to operate. The base station node comprises a processing unit configured to: detect that the wireless device transmits via the repeater; and schedule the wireless device only on the sub-band of the repeater.

The object is, according to a third aspect, achieved by a computer program for a base station node of a communication system comprising a repeater configured to receive and retransmit signaling between the base station node and a wireless device. The repeater is configured to operate on a sub-band of a frequency band on which the base station node is configured to operate. The computer program comprises computer program code, which, when run on a processing unit of the base station node, causes the processing unit to perform the steps of: detecting that the wireless device transmits via the repeater; and scheduling the wireless device only on the sub-band of the repeater.

The object is, according to a fourth aspect, achieved by a computer program product comprising a computer program as above, and computer readable means on which the computer program is stored.

Further features and advantages of the disclosure will become clear upon reading the following description and the accompanying

drawings .

Brief description of the drawings Figure 1 illustrates schematically an environment in which

embodiments of the present disclosure may be implemented.

Figure 2 is a flow chart of a method of the present disclosure. Figure 3 illustrates an embodiment of detecting a wireless device.

Figure 4 illustrates an environment in which embodiments of the present disclosure may be implemented.

Figure 5 illustrates an environment in which embodiments of the present disclosure may be implemented.

Figure 6 illustrates a base station node comprising means for implementing aspects of the present disclosure.

Detailed description of embodiments

In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular architectures, interfaces, techniques, etc. in order to provide a thorough understanding. In other instances, detailed descriptions of well-known devices, circuits, and methods are omitted so as not to obscure the description with unnecessary detail. Same reference numerals refer to same or similar elements throughout the

description .

Figure 1 illustrates schematically an environment in which

embodiments of the present disclosure may be implemented. In particular, figure 1 illustrates a communication system 1 comprising one or more base station nodes 2 (only one illustrated in the figure) configured to provide wireless communication links for a number of wireless devices 4. The wireless device 4 is a device able to receive and/or transmit wirelessly, and should be construed as encompassing various types of devices such as a mobile phone, smart phone, laptops. Depending on type of device, and sometimes also depending on communication system in which it is used, the wireless device may be denoted in various ways, for example user equipment.

The base station node 2 may, as a particular example be an evolved Node B, also denoted eNB, in case the communication system 1 is a Long Term Evolution (LTE) system. It is noted that different communication systems use different terms for indicating a base station node; for example, in a communication system adopting the GSM standard, the term base transceiver station is commonly used, in yet other communication systems other terms are used. The communication system 1 further comprises one or more repeaters 3 (only one illustrated in the figure) configured to receive and retransmit signaling between the base station node 2 and a wireless device 4. The repeater 3 may be configured to amplify radio signals in downlink, i.e. signaling from the base station node 2 to the wireless device 4, and uplink, i.e. signaling from the wireless device 4 to the base station node 2. However, in other embodiments, the repeater 3 is connected to the base station node 2 in a wired fashion, e.g. by means of communication cables such as optical fiber cables. In such embodiments there is no need for signaling over a radio interface between the repeater 3 and the base station node 2, only between the repeater 3 and the wireless device 4.

The repeater 3 may, particularly if it is in wired communication with the base station node 2, be configured to be updated by the base station node 2, e.g. by receiving updating information. As a particular example, the base station node 2 may update the sub-band that the repeater 3 uses, e.g. in that the sub-band may be changed or another sub-band be added. In various of the embodiments of the present disclosure, it is assumed that the wireless device 4 cannot be reached by signaling from the base station node 2, nor that the wireless device 4 can signal directly to the base station node 2 : the wireless device 4 cannot "hear" the base station node 2. The repeater 3 is configured to operate on a frequency sub-band of a frequency band on which the base station node 2 is configured to operate. That is, the repeater 3 is a frequency sub-band repeater, in the following denoted sub-band repeater 3 or simply repeater 3. It is noted that the repeater 3 may be configured to receive and transmit on one or more frequency sub-bands of the frequency band that the base station node 2 operates (i.e. on which the base station node 2 transmits and receives) . However, the more sub-bands the sub-band repeater 3 is configured with, the more complexity is added to it. The sub-band or sub-bands of choice in a particular sub-band repeater 3 may be implemented e.g. by a band-pass filter or by a band-stop filter. The band-pass filter, passing frequencies within a desired sub-band range and rejecting (attenuating) frequencies outside that range, may comprise known filter devices. The band-stop filter, sometimes denoted band-rejection filter, stopping

frequencies outside the desired frequencies (e.g. the desired sub- band), may for example be a notch filter.

Briefly, in an aspect, advanced algorithms needed for detecting what sub-band repeater 3 a particular wireless device 4 is using is located in and performed by the base station node 2, whereby repeaters may be used instead of expensive relays . The sub-band repeaters 3 that are used may be cost-efficient, low complexity repeaters without any specially developed software or hardware, nor do they require to be enabled to communicate with the base station node 2. The sub-band repeater 3 may for example be a simple

standardized LTE repeater provided with a band-pass filter or band- stop filter when the communication system 1 comprises an LTE system.

Different sub-bands may be used for different sub-band repeaters 3 and a method implemented in the base station node 2 automatically finds out what sub-band repeater a wireless device 4 is using, and then schedules the wireless device 4 only in the detected sub-band.

Figure 2 is a flow chart of a method of the present disclosure. The method 10 is implemented and performed in a base station node 2 of a communication system 1, such as the communication system described with reference to figure 1. The communication system 1 thus

comprises a repeater 3 configured to receive and retransmit

signaling between the base station node 2 and a wireless device 4. The repeater 3 is configured to operate on a sub-band of a frequency band on which the base station node 2 is configured to operate. That is, the repeater 3 is a frequency sub-band repeater. It is again noted that the repeater 3 may be configured to receive and transmit on one or more sub-bands of the frequency band that the base station node 2 operates, i.e. of the frequency band that the base station node 2 uses for transmitting and receiving signaling. The method 10 comprises detecting 11 that the wireless device 4 transmits via the repeater 3. This detection can be accomplished in various ways as will be described below in various embodiments of the method 10 and also with reference to figure 3. The method 10 further comprises scheduling 12 the wireless device 4 only on the sub-band of the repeater 3. By scheduling the wireless device 4 only on the sub-band that it can "hear", a number of advantages are obtained. For example, the interference towards other wireless devices may be reduced as well as inter-cell interference on uplink.

In various embodiments, the detecting 11 that the wireless device 4 transmits via the repeater 3 is based on signaling transmitted by the wireless device 4. That is, in different embodiments, different types of signaling transmitted by the wireless device 4 form the basis upon which the base station node 2 is configured to detect which sub-band the wireless device 4 "hears".

In an embodiment, the detecting 11 that the wireless device 4 transmits via the repeater 3 comprises : receiving a sounding reference signal transmitted by the wireless device 4, and detecting that the wireless device 4 transmits via the repeater 3 by detecting that the sounding reference signal is received only on the sub-band of the repeater 3. This is described more in detail with reference to figure 3, which thus illustrates an embodiment of detecting the wireless device 4. In particular, and with reference now to figure 3, the wireless device 4 transmits sounding reference signals (SRS) (arrow 100) using its entire frequency band (illustrated at reference numeral 110) on which it is configured to operate. That is, the wireless device 4 sends SRSs for the whole frequency band. The base station node 2 cannot hear this sounding signal directly, e.g. because the wireless device 4 is too far from it or shadowed by buildings. The sounding signal is however received by the sub-band repeater 3, which is configured to operate on a sub-band of the frequency band on which the base station node 2 is configured to operate. This sub- band of the entire frequency band 110 is illustrated by the hatched area at reference numeral 120. The base station node 2 thus receives the sounding signal 100 via the repeater 3. The base station node 2 further detects that only the sounding reference signals from the repeated sub-band (reference numeral 130) are received, and is thereby able to detect the correct sub-band, i.e. the sub-band that the wireless device 4 can hear (since it is out of reach of the base station node 2 directly) . If the base station node 2 should receive sounding reference signals from the wireless device 4 in its entire bandwidth, then the base station node 2 can deduce that no repeater is used.

It is noted that the base station node 2 and the wireless device 4 are typically configured to operate on the same frequency band.

In an embodiment, the detecting 11 that the wireless device 4 transmits via the repeater 3 comprises : receiving a channel quality indicator (CQI) report transmitted by the wireless device 4, and detecting that the wireless device 4 transmits via the repeater 3 by detecting that a channel quality indicator parameter for the sub- band of the repeater 3 is the highest of all channel quality indicator parameters of the received channel quality indicator report. The wireless device 4 may be configured to transmit such CQI reports on a regular basis or when being instructed by the base station node 2 to send such a CQI report. The CQI report is

typically based on measurements made by the wireless device 4 on reference signals transmitted by the base station node 2. As the wireless device 4 only hears the signaling on the sub-band of the repeater 3, the CQI values for this sub-band are the highest. The base station node 2 is thereby able to detect the correct sub-band.

In an embodiment, the detecting 11 that the wireless device 4 transmits via the repeater 3 comprises: - receiving a control channel transmitted by the wireless device 4,

- measuring power of the control channel, and

- detecting that the wireless device 4 transmits via the repeater 3 by detecting that the power is above a threshold value. In an embodiment, a variation of the above, the communication system

1 comprises an LTE system. In LTE one particular control channel, the Physical Uplink Control Channel (PUCCH) , is located at a respective end of the frequency band on which the base station node 2 is configured to operate. The detecting 11 that the wireless device 4 transmits via the repeater 3 comprises detecting the PUCCH at only one end of the frequency band on which the base station node

2 is configured to operate. That is, if the base station node 2 only detects one PUCCH, then it can detect that the wireless device 4 is on a repeater from that sub-band. In this embodiment, only two sub- bands can be used (upper and lower) in the repeaters for the base station to be able to detect correct repeater. If the base station node 2 receives both PUCCH it can conclude that the wireless device 4 does not communicate via the repeater 3. In an embodiment, the detecting 11 that the wireless device 4 transmits via the repeater 3 comprises:

- transmitting, to the wireless device 4, data packets utilizing different sub-bands of the frequency band on which the base station node 2 is configured to operate, and - detecting that the wireless device 4 transmits via the repeater 3 by receiving a message sent from the wireless device 4 only in response to a data packet transmitted on the sub-band corresponding to the sub-band of the repeater 3.

In this embodiment thus, the base station node 2 detects that the wireless device 4 transmits via the repeater 3 simply by "testing", i.e. by sending out data packets using different frequencies (of different sub-bands) . If it receives a message from the wireless device 4 in response to one such data packet, then it is able to detect the correct sub-band on which to schedule the wireless device 4.

For example, the base station node 2 may send uplink grant messages in different sub-bands to the wireless device 4, upon which the wireless device 4 responds to the uplink grant message on the sub- band that it "hears". As another example, the base station node 2 may send downlink data in different sub-bands, and if e.g. an acknowledgment is received from the wireless device 4 on a data message sent on a particular sub-band, the base station node 2 may, based on this, detect which sub-band the wireless device 4 "hears". In an embodiment, the scheduling 12 comprises frequency selective scheduling. The frequency selective scheduling can be used to only schedule the sub-band that has been detected for the wireless device 4 . That is, the wireless device 4 that has been detected on the repeater 3 is scheduled only on the sub-band on which this repeater 3 operates. The base station node 2 thus allocates adjacent

subcarriers located within the sub-band, e.g. of a small bandwidth, on which the wireless device 4 has the most favorable channel conditions. The frequency selective scheduling is applicable both for downlink (DL) and uplink (UL) . The repeaters 3 connected to a particular base station node 2 may be "cell planned", so that they use different sub-bands. When

configuring the communication system 1 , the sub-band repeaters, and particularly which sub-bands they are to use, may be planned in view of e.g. sub-band repeaters of neighboring cells. The base station node 2 may also be configured with the geographical location of the particular sub-band repeaters within its cell/cells. As a particular example, a repeater 3 may typically be located close to the cell border of the cell serviced by the base station node 2 to which it is connected. Two such repeaters, located close to their respective cell borders, should preferably use different sub-bands. The interference level in the communication system 1 can thereby be maintained even with the introduction of the repeaters 3 . This can be seen as interference cancellation by repeater planning

Figure 4 illustrates an environment in which embodiments of the present disclosure may be implemented. In particular, the figure illustrates an indoor environment, wherein a sub-band repeater 3χ , 3₂ , 3_3f 3₄ has been placed on a respective floor in a building. The first repeater 3χ is configured to operate on a first sub-band (reference numeral 210 ) of the entire frequency band (indicated at reference numeral 200 ) on which the base station node 2 operates. Correspondingly, a second repeater 3₂ is configured to operate on a second sub-band (reference numeral 220 ) , a third repeater 3₃ is configured to operate on a third sub-band (reference numeral 230 ) a fourth repeater 3₄ is configured to operate on a fourth sub-band (reference numeral 240 ) . The four sub-band repeaters 3χ , 3₂ , 3₃, 3₄ may be seen as under-laid cells (e.g. pico cells, femto cells or micro cells) to an overlaid cell (e.g. macro cell) provided by the base station node 2 . In the illustrated case, the four sub-band repeaters 3χ , 3₂ , 3₃, 3₄ together cover the whole frequency band of the base station node 2 . In other embodiments, a higher or lower number of repeaters may be used, together covering the whole frequency band or only parts thereof.

A wireless device 4 , 5 , 6 , 7 on the respective floors can thus communicate via a respective sub-band repeater 3χ , 3₂ , 3₃, 3₄ . The base station node 2 is able to detect the wireless devices 4 , 5 , 6 , 7 being on the respective sub-bands (i.e. transmitting via a respective sub-band repeater 3χ , 3₂ , 3_3, 3₄ ) , for example by any of the described ways of detecting. The base station node 2 is further able to schedule the wireless devices 4 , 5 , 6 , 7 only on the respective sub-bands. The interference can be reduced, in particular intra-cell interference, by having different cells on the different floors, the cells using different sub-bands.

Just for sake of completeness, it is noted that a wireless device 8 located in the macro cell, may typically be scheduled on the full frequency band (reference numeral 200 ) as it can hear the base station node 2 .

Figure 5 illustrates an environment in which embodiments of the present disclosure may be implemented. A first and a second wireless device 4 , 5 are illustrated as located in a region close to or at the cell border between a first and a second base station node 2χ ,

2₂ . Without the use of repeaters, the wireless devices 4 , 5 could be without coverage as it could possibly be unable to hear the base station node 2 even when transmitting on the highest power level allowable. Repeaters are typically introduced in communication systems in order to provide coverage, i.e. in order to "reach" these wireless devices, but at the expense of increased interference. In an aspect of the present disclosure, the introduction of repeaters is enabled without such increased interference.

In particular, a first and a second repeater 3_lr 3₂ are placed at the cell border and configured to operate on different sub-bands; the first repeater 3₁ is configured to operate on a first sub-band 210 and the second repeater 3₂ is configured to operate on a second sub- band 220, the first and second sub-bands 210, 220 differing from each other. The wireless devices 4, 5, not hearing the base station nodes 2_lr 2₂ directly, communicate via a respective repeater 3_lr 3₂ on a respective sub-band, whereby interference is limited. The

repeaters 3_lr 3₂ are "cell-planned", i.e. the respective sub-bands are chosen suitably so as to minimize the interference created. That is, the wireless devices 4, 5 communicate on sub-bands that do not interfere with the transmission from their respective neighboring base stations. For sake of completeness it is noted that wireless devices 8χ, 8₂ that are able to hear a respective base station node 2i, 2₂ may, in conventional manner, be scheduled on the whole frequency spectrum 110 allocated for such communication. From the above description, in particular figures 4 and 5, it is evident that the disclosure provides improvements for e.g. in-door and other "cell-edge" users, providing improved coverage without increasing the interference within the communication system 1.

Different ICIC features and HetNet CoMP (Heterogeneous Network Coordinated multipoint) features may be combined with the various described embodiments. For example, antenna beam-forming may be combined with embodiments of the present disclosure. In particular, since a base station node 2 is aware of the fact that the wireless device 4 communicates via a repeater 3, and since, as described earlier, the base station node 2 may be configured with the

geographical location of the particular sub-band repeaters within its cell/cells, it also has knowledge of the location of the wireless device 4 to a rather accurate degree. The base station node 2 may thereby choose a suitable antenna beam, e.g. directed narrow antenna beam, towards the repeater 3 for communication therewith. As another example, various ICIC algorithms could benefit from the knowledge of what sub-bands are used and also the geographical locations. Information about the environment and geographical location of the repeaters can be combined so that scheduling, power control, and link adaption is optimized in best way for the wireless device 4 communicating via a particular repeater 3, and also for other wireless devices located in the macro cell provided by the base station node 2.

Figure 6 illustrates a base station node 2 comprising means for implementing aspects of the present disclosure. The base station node 2 is part of the communication system 1 as described with reference to e.g. figure 1, comprising a repeater 3 configured to receive and retransmit signaling between the base station node 2 and a wireless device 4. The base station node 2 comprises a transmitter device 21 and a receiver device 22 enabling communication with wireless devices 4 and repeaters 3. Such transmitter device 21 and receiver device 22 comprises conventionally used circuitry, such as for example modulator/demodulator circuitry, encoding/decoding circuitry, equalization, pre-coding etc. The transmitter device 21 and the receiver device 22 further comprises or is connected to antennas by means of which signaling is received/transmitted. It is noted that the base station node 2 typically comprises further components and circuitry conventionally used for performing e.g. various signal processing, for example combiners, duplexers, power amplifiers etc.

The base station node 2 further comprises a processing unit 23 receiving data from the receiver device 22 and providing data to the transmitter device 21. The processing unit 23 is configured to perform the various embodiments of the method as described. The processing unit 23 may for example be a central processing unit (CPU), microcontroller, digital signal processor (DSP), etc., capable of executing software instructions, e.g. a computer program 24, stored in a computer program product 25 e.g. in the form of a memory. The processing unit 23 is thus able to retrieve data and/or instructions from such computer program product 25. In particular, the processing unit 23 may be configured to:

- detect that the wireless device 4 transmits via the repeater 3, and

- schedule the wireless device 4 only on the sub-band of the repeater 3.

In an embodiment, the processing unit 23 is configured to schedule by means of frequency selective scheduling.

In an embodiment, the processing unit 23 is configured to detect that the wireless device 4 transmits via the repeater 3 based on signaling transmitted by the wireless device 4.

In an embodiment, the processing unit 23 is configured to detect that the wireless device 4 transmits via the repeater 3 by:

- receiving a sounding reference signal transmitted by the wireless device 4, and - detecting that the wireless device 4 transmits via the repeater 3 by detecting that the sounding reference signal is received only on the sub-band of the repeater 3.

In an embodiment, the processing unit 23 is configured to detect that the wireless device 4 transmits via the repeater 3 by: - receiving a channel quality indicator report transmitted by the wireless device 4, and

- detecting that the wireless device 4 transmits via the repeater 3 by detecting that a channel quality indicator parameter for the sub- band of the repeater 3 is the highest of all channel quality indicator parameters of the received channel quality indicator report .

- receiving a control channel transmitted by the wireless device 4, - measuring power of the control channel, and

- detecting that the wireless device 4 transmits via the repeater 3 by detecting that the power is above a threshold value.

In an embodiment, the communication system 1 comprises a Long Term Evolution system wherein a physical uplink control channel, PUCCH, is located at a respective end of the frequency band on which the base station node 2 is configured to operate. The processing unit 23 is configured to detect that the wireless device 4 transmits via the repeater by detecting the physical uplink control channel at only one end of the frequency band on which the base station node 2 is configured to operate.

- transmitting, to the wireless device 4, data packets utilizing different sub-bands of the frequency band on which the base station node 2 is configured to operate, and

- detecting that the wireless device 4 transmits via the repeater 3 by receiving a message sent from the wireless device 4 only in response to a data packet transmitted on the sub-band corresponding to the sub-band of the repeater 3.

It is noted that the methods may be implemented in software, hardware or any combinations thereof.

In an aspect, a computer program 24 is provided for the base station node 2. The computer program 24 comprises computer program code for cooperation with the processing unit 23.

The computer program 24 is provided in the base station node 2 of a communication system, such as the system described with reference to figure 1, and in particular in the processing unit 23 of the base station node 2 or otherwise accessible by the processing unit 23. The computer program 24 comprises computer program code, which, when run on or by the processing unit 23 of the base station node 2, causes the processing unit 23 to perform the steps of: - detecting that the wireless device 4 transmits via the repeater 3, and

- scheduling the wireless device 4 only on the sub-band of the repeater 3. In an aspect of the disclosure, a computer program product 25 is provided. The computer program product 25 comprises a computer program 24 as described above and a computer readable means on which the computer program 24 is stored. The computer program product 25 may for example comprise any combination of read and write memory (RAM) or read only memory (ROM) . The computer program product 25 may also comprise persistent storage, which, for example can be any single one or combination of magnetic memory, optical memory, or solid state memory.

Claims

1. A method (10) performed in a base station node (2) of a

communication system (1), the communication system (1) comprising a repeater (3) configured to receive and retransmit signaling between the base station node (2) and a wireless device (4), the repeater

(3) being configured to operate on a sub-band of a frequency band on which the base station node (2) is configured to operate, the method

(10) comprising:

- detecting (11) that the wireless device (4) transmits via the repeater (3), and

- scheduling (12) the wireless device (4) only on the sub-band of the repeater (3).

2. The method (10) as claimed in claim 1, wherein the scheduling (12) comprises frequency selective scheduling.

3. The method (10) as claimed in claim 1 or 2, wherein the detecting

(11) that the wireless device (4) transmits via the repeater (3) is based on signaling transmitted by the wireless device (4) .

4. The method (10) as claimed in any of claims 1-3, wherein the detecting (11) comprises: - receiving a sounding reference signal transmitted by the wireless device ( 4 ) , and

- detecting that the wireless device (4) transmits via the repeater (3) by detecting that the sounding reference signal is received only on the sub-band of the repeater (3) .

5. The method (10) as claimed in any of claims 1-3, wherein the detecting (11) comprises:

- receiving a channel quality indicator report transmitted by the wireless device (4), and

- detecting that the wireless device (4) transmits via the repeater (3) by detecting that a channel quality indicator parameter for the sub-band of the repeater (3) is the highest of all channel quality indicator parameters of the received channel quality indicator report .

6. The method (10) as claimed in any of claims 1-3, wherein the detecting (11) comprises:

- receiving a control channel transmitted by the wireless device (4) ,

- measuring power of the control channel, and

- detecting that the wireless device (4) transmits via the repeater (3) by detecting that the power is above a threshold value.

7. The method (10) as claimed in any of claims 1-3, wherein the communication system (1) comprises a Long Term Evolution system wherein a physical uplink control channel, PUCCH, is located at a respective end of the frequency band on which the base station node (2) is configured to operate, and wherein the detecting (11) that the wireless device (4) transmits via the repeater (3) comprises detecting the physical uplink control channel at only one end of the frequency band on which the base station node (2) is configured to operate .

8. The method (10) as claimed in any of claims 1-3, wherein the detecting (11) comprises:

- transmitting, to the wireless device (4), data packets utilizing different sub-bands of the frequency band on which the base station node (2) is configured to operate, and - detecting that the wireless device (4) transmits via the repeater (3) by receiving a message sent from the wireless device (4) only in response to a data packet transmitted on the sub-band corresponding to the sub-band of the repeater (3) .

9. A base station node (2) of a communication system (1) comprising a repeater (3) configured to receive and retransmit signaling between the base station node (2) and a wireless device (4), the repeater (3) being configured to operate on a sub-band of a frequency band on which the base station node (2) is configured to operate, the base station node (2) comprising a processing unit (23) configured to:

- detect that the wireless device (4) transmits via the repeater ( 3 ) , and

- schedule the wireless device (4) only on the sub-band of the repeater ( 3 ) .

10. The base station node (2) as claimed in claim 9, wherein the processing unit (23) is configured to schedule by means of frequency selective scheduling.

11. The base station node (2) as claimed in claim 9 or 10, wherein the processing unit (23) is configured to detect that the wireless device (4) transmits via the repeater (3) based on signaling transmitted by the wireless device (4) .

12. The base station node (2) as claimed in claim 9, 10 or 11, wherein the processing unit (23) is configured to detect that the wireless device (4) transmits via the repeater by:

- receiving a sounding reference signal transmitted by the wireless device ( 4 ) , and - detecting that the wireless device (4) transmits via the repeater (3) by detecting that the sounding reference signal is received only on the sub-band of the repeater (3) .

13. The base station node (2) as claimed in claim 9, 10 or 11, wherein the processing unit (23) is configured to detect that the wireless device (4) transmits via the repeater (3) by:

14. The base station node (2) as claimed in claim 9, 10 or 11, wherein the processing unit (23) is configured to detect that the wireless device (4) transmits via the repeater (3) by:

- receiving a control channel transmitted by the wireless device (4) ,

- measuring power of the control channel, and

15. The base station node (2) as claimed in claim 9, 10 or 11, wherein the communication system (1) comprises a Long Term Evolution system wherein a physical uplink control channel, PUCCH, is located at a respective end of the frequency band on which the base station node (2) is configured to operate, and wherein the processing unit (23) is configured to detect that the wireless device (4) transmits via the repeater by detecting the physical uplink control channel at only one end of the frequency band on which the base station node

(2) is configured to operate.

16. The base station node (2) as claimed in claim 9, 10 or 11, wherein the processing unit (23) is configured to detect that the wireless device (4) transmits via the repeater (3) by:

- transmitting, to the wireless device (4), data packets utilizing different sub-bands of the frequency band on which the base station node (2) is configured to operate, and

- detecting that the wireless device (4) transmits via the repeater

(3) by receiving a message sent from the wireless device (4) only in response to a data packet transmitted on the sub-band corresponding to the sub-band of the repeater (3) .

17. A computer program (24) for a base station node (2) of a communication system (1) comprising a repeater (3) configured to receive and retransmit signaling between the base station node (2) and a wireless device (4), the repeater (3) being configured to operate on a sub-band of a frequency band on which the base station node (2) is configured to operate, the computer program (24) comprising computer program code, which, when run on a processing unit (23) of the base station node (2), causes the processing unit

(23) to perform the steps of:

- detecting that the wireless device (4) transmits via the repeater ( 3 ) , and

- scheduling the wireless device (4) only on the sub-band of the repeater ( 3 ) .

18. A computer program product (25) comprising a computer program

(24) as claimed in claim 17, and computer readable means on which the computer program (24) is stored.