GB2544120A

GB2544120A - Systems and methods for measuring signals

Info

Publication number: GB2544120A
Application number: GB1519763.5A
Authority: GB
Inventors: Toledano Ron
Original assignee: TCL Communication Ltd
Current assignee: TCL Communication Ltd
Priority date: 2015-11-09
Filing date: 2015-11-09
Publication date: 2017-05-10
Anticipated expiration: 2035-11-09
Also published as: GB2544120B; CN108293234B; GB201519763D0; WO2017080372A1; CN108293234A

Abstract

A method for a User Equipment (UE) measuring neighbouring cell 208/210 signals where the UE may have no information on the timing/frequency of synchronisation signals from the cells: comprises receiving, by a first UE 202 from a second UE 204, information on the time at which synchronisation signals are received at the second UE from one or more base stations to which the first and second UEs are not connected; and obtaining, by the first UE based on the received information, a timing pattern for detecting, by the first UE, synchronisation signals transmitted from the one or more base stations. Information on the time at which synchronisation signals are received at the second UE allow enhanced measurement gap patterns to be determined based on the information. The information is transmitted from the second to the first UE via a Device-to-Device (D2D) link. Also disclosed is a method comprising: receiving from a second UE, information on one or more frequencies at which synchronisation signals are transmitted from one or more base stations to which the UEs are not connected, and using said information on one or more frequencies for detecting synchronisation signals transmitted from the one or more base stations.

Description

SYSTEMS AND METHODS FOR MEASURING SIGNALS TECHNICAL FIELD

[0001] Embodiments of the present invention generally relate to systems and methods for use in telecommunication networks. More specifically, they relate to systems and methods that facilitate measurements of signals.

BACKGROUND

[0002] In a cellular network, the areas where the network is distributed are covered by cells, each served by at least one base station (commonly known as a NodeB in a 3G network and an eNodeB in a 4G network). Mobile equipment (UE) located within a serving cell is connected to the telecommunications core network via the base station of the serving cell. A set of base stations forms a radio access network (RAN). Each cell typically abuts one or more neighbouring cells. UEs are required to measure the signal quality and/or the signal strength of signals of neighbouring cells from time to time, in order to determine which cell among the neighbouring cell(s) may be able to serve the UE. Those measurements are transmitted to the serving cell. The current serving base station may then decide to hand over the UE to one of the neighbouring cells based on the measurements and other criteria such as traffic load and/or cell priorities.

[0003] A UE typically measures signals of neighbouring cells following detection of synchronisation signals (SS) from the cells, but the UE may have no information on the timing or frequency of those signals. The time at which the synchronisation signals from a neighbouring cell are received at a UE depends on 1) the time when the synchronisation signals are transmitted from the base station of the neighbouring cell (typically base stations are not synchronised and their timing relationship is arbitrary), and 2) the time of flight between the base station of the neighbouring cell and the UE, which may be variable and depend on the distance between the UE and the base station. For inter-frequency and inter-RAT (Radio Access Technology) neighbouring cells, locating the synchronisation signals can be time consuming and the UE may not be available to communicate with its current serving base station while detecting the synchronisation signals.

[0004] A UE having more radio units than the ones currently in use for communication with a serving cell, can, to some extent, use a surplus radio unit for detecting synchronisation signals from neighbouring cells while still remaining available for its current serving cell. Otherwise, for a UE having one radio unit, the network has to assign periodic measurement gaps to the UE which are dedicated to the measurement of signals from neighbouring cells, such as the synchronisation signals, and are not expected to be used for data communication or signalling between the UE and its current serving cell.

[0005] Within the duration of the measurement gaps, the UE attempts to measure signals from neighbouring cell(s). The duration of the measurement gaps should be long enough to allow a UE to detect signals from neighbouring cells and to perform accurate measurements of those signals.

[0006] Figure 1a shows a system 100 having a UE 102 located within a serving cell 106. The area covered by serving cell 106 is defined by the signal coverage of the base station 104. The serving cell 106 has neighbouring cells 108 and 110 (the cells are shown schematically in the conventional manner). Although only two neighbouring cells are shown in Figure 1a, the serving cell may have more than two neighbouring cells. The base station of the neighbouring cells and that of the serving cell may operate at different carrier frequencies or using different Radio Access Technologies.

[0007] Figure 1b illustrates measurement gaps 112 with a gap periodicity 114. During the windows of the measurement gaps 112, the UE 102 attempts to detect synchronisation signals from the neighbouring cell(s) 108 and 110. At the time outside the window of the measurement gaps 112, the UE 102 can communicate with the base station 104 of the serving cell 106, for example it may transmit data and/or control signals to the base station 104.

[0008] As the number of carrier frequencies deployed grows to support mobility of UEs the task for UEs to monitor the signals of neighbouring cells can become more time and resource consuming. For the UE, detecting a larger number of carriers from neighbouring cells would lead to more power consumption, which is not used for data transfer with its serving cell. Longer measurement gaps also give fewer scheduling opportunities with the UE and smaller total data throughputs.

[0009] The embodiments of the present invention provide improved techniques for facilitating measurements of signals of neighbouring cells.

[0010] The embodiments described below are not limited to implementations which solve any or all of the disadvantages of known systems.

SUMMARY

[0011] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0012] According to a first aspect of the present invention, there is provided a method comprising receiving, by a first User Equipment (UE) from a second UE, information on the time at which synchronisation signals are received at the second UE from one or more base stations to which the first and second UEs are not connected; and obtaining, by the first UE based on the received information, a timing pattern for detecting, by the first UE, synchronisation signals transmitted from the one or more base stations.

[0013] In one embodiment, said obtaining the timing pattern comprises obtaining, by the first UE, one or more measurement gap patterns for detecting synchronisation signals from the one or more base stations.

[0014] In another embodiment, said obtaining one or more measurement gap patterns comprises sending, from the first UE to a serving base station, an indication that a pre determined enhanced measurement gap pattern is to be selected for use, and receiving, by the first UE from the serving base station, said enhanced measurement gap pattern for use by the first UE.

[0015] In another embodiment, said obtaining one or more measurement gap patterns comprises sending, from the first or the second UE to the serving base station, the information on the time at which synchronisation signals are received at the second UE from the one or more base stations, and receiving, by the first UE from the serving base station, an enhanced measurement gap pattern determined based on the information.

[0016] In another embodiment, the method further comprises, if it is determined that the received information is suitable for use by the first UE for detection of synchronisation signals, detecting, by the first UE within the one or more measurement gap patterns, synchronisation signals transmitted from the one or more base stations.

[0017] In another embodiment, the method further comprises if it is determined that the received information is not suitable for use by the first UE for detection of synchronisation signals, using, by the first UE, a legacy measurement gap pattern for detecting synchronisation signals from the one or more base stations.

[0018] In another embodiment, the first UE comprises a plurality of radio units, and the timing pattern is used by one of the radio units for detecting synchronisation signals from the one or more base stations.

[0019] In another embodiment, the method further comprises receiving, by the first UE from the second UE, information on one or more frequencies at which synchronisation signals are transmitted from the one or more base stations to which the first and second UEs are not connected, and using, by the first UE, said information on one or more frequencies for detecting synchronisation signals transmitted from the one or more base stations.

[0020] According to a second aspect of the present invention, there is provided a method for determining a timing pattern for use by a first User Equipment (UE) to detect signals in a telecommunication network, the method comprising: obtaining, by a second UE, the timings at which synchronisation signals are received at the second UE from one or more base stations to which the first and second UEs are not connected; transmitting, by the second UE, said timings to the first UE or a serving base station so that the timing information is available for use by the first UE or the serving base station to determine a timing pattern for detecting by the first UE synchronisation signals from the one or more base stations.

[0021] In one embodiment, the information is transmitted from the second UE to the first UE via a Device-to-Device (D2D) link.

[0022] According to a third aspect of the present invention, there is provided a method for determining one or more measurement gap patterns for a first User Equipment (UE) in a telecommunication network, comprising receiving, by a base station, an indication that an enhanced measurement gap pattern can be assigned to the first UE or information on timings at which a second UE receives synchronisation signals from one or more base stations to which the first and second UEs are not connected; determining, by the base station, an enhanced measurement gap patterns to allow the first UE to detect the synchronisation signals, the determining being based on the received indication or the received information on timings, and assigning, by the base station, the determined one or more measurement gap patterns to the first UE.

[0023] In one embodiment, the method further comprises determining, by the base station, if information on timings of receipt of synchronisation signals received by the first UE from the second UE is suitable for use by the first UE for detection of synchronisation signals, wherein the determining and assigning of one or more measurement gap patterns only occur if it is determined that they are suitable for such use.

[0024] In another embodiment, said determining if the information on timings of receipt of synchronisation signals is suitable for use by the first UE is made based on at least one of a distance between UE1 and UE2; a comparison of a Round-Trip Time (RTT) for UE1 and the difference between RTT for UE1 and RTT for UE2; and a mobility of UE1 and/or UE2.

[0025] According to a forth aspect of the present invention, there is provided A method comprising: receiving, by a first UE from a second UE, information on one or more frequencies at which synchronisation signals are transmitted from one or more base stations to which the first and second UEs are not connected, and using, by the first UE, said information on one or more frequencies for detecting synchronisation signals transmitted from the one or more base stations.

[0026] According to a fifth aspect of the present invention, there is provided a method for facilitating signal detection by a first UE in a telecommunication network, the method comprising: obtaining, by a second UE, one or more frequencies at which synchronisation signals are received at the second UE from one or more base stations; transmitting, by the second UE to the first UE, information on said one or more frequencies so that it is available for use by the first UE for detecting synchronisation signals from the one or more base stations.

[0027] In one embodiment, the information is transmitted from the second UE to the first UE via a D2D link.

[0028] In one embodiment, the first UE and the second UE are connected to the same base station.

[0029] According to a fifth aspect of the present invention, there is provided an apparatus, comprising means for performing the method according to any of the above aspects or embodiments of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Embodiments of the invention will be described, by way of example, with reference to the following drawings, in which: [0031] Figures 1a is a schematic diagram showing a UE within a serving cell abutting a plurality of neighbouring cells.

[0032] Figure 1 b is a schematic diagram illustrating measurement gaps.

[0033] Figure 2 is a schematic diagram illustrating a system for optimising a length of measurement gaps according to one embodiment of the present invention.

[0034] Figure 3 is a schematic diagram illustrating a shortened measurement gap length (MGL) that can be obtained according to one embodiment of the present invention.

[0035] Figure 4 is a flow chart describing a method according to one embodiment of the present invention.

DETAILED DESCRIPTION

[0036] Embodiments of the present invention are described below by way of example only. These examples represent the best ways of putting the invention into practice that are currently known to the Applicant although they are not the only ways in which this could be achieved. The description sets forth the functions of the example and the sequence of steps for constructing and operating the example. However, the same or equivalent functions and sequences may be accomplished by different examples.

[0037] Embodiments of the present invention provide a method and system in which a first UE receives from a second UE information on synchronisation signals from one or more neighbouring cells. Such information may indicate the timing and/or frequencies of synchronisation signals for neighbouring cells measured by other nearby UE(s). This may help reduce the time and processing effort used for performing measurements on neighbouring cells.

[0038] Preferably, such information is received via a Device-to-Device (D2D) link from the second UE. As known in the art, D2D is a telecommunication method that allows direct communications between terminal devices (UEs) in a network.

[0039] In one embodiment, the first UE detects synchronisation signals from neighbouring cells without measurement gaps. This may be due to the first UE having more than one radio unit / transceiver such that it can dedicate a surplus radio unit / transceiver for detecting those signals. In this case, the first UE may receive from the second UE information on synchronisation signals from one or more neighbouring cells. Such information may indicate the timing and/or frequencies of synchronisation signals for neighbouring cells measured by other nearby UE(s). The first UE may use such information for detecting synchronisation signals from neighbouring cells, e.g. using such information to deduce a timing pattern defining timings at which the synchronisation signals from neighbouring cells can be detected by the first UE. This information may help reduce the processing power required by the first UE to detect synchronisation signals from neighbouring cells.

[0040] Where measurement gaps are used for detecting synchronisation signals, a measurement gap pattern, which defines timings of the measurement gaps, is assigned to the first UE, based on information provided by other UE(s) in its proximity. In one embodiment, the measurement gaps assigned to the first UE may be shorter than a legacy (default) measurement gap and may have the minimum length that is required to cover the synchronisation signals from neighbouring cells within a single measurement period. In another embodiment, the measurement gap pattern may define a plurality of discrete measurement gaps within a single measurement period. Each of these discrete measurement gaps may correspond to synchronisation signals from a particular neighbouring cell.

[0041] Figure 2 is a schematic diagram illustrating a system 200 according to one embodiment of the present invention. As shown in Figure 2, a first UE, UE1 202, is located within the coverage of serving cell 206, and is also within the proximity of a second UE, UE2 204. UE1 and UE2 may be connected to the same base station 212. UE1 and UE2 may be capable of communicating with each other using a D2D link. UE2 may obtain information on synchronisation signals from neighbour cell(s). The information may include timing and frequency of synchronisation signals received at UE2 and cell identity for a cell detected by UE2. This information may be obtained in a conventional way, for example, by the UE2 measuring the signals of neighbour cells without prior knowledge of the timing and/or frequency of these signals.

[0042] If UE1 and UE2 are sufficiently close to each other, the time of arrival of synchronisation signals from a neighbouring cell 208, 210 measured at the location of UE2 may be almost identical to that at the location of UE1. UE1 can utilise the timing and/or frequency information from UE2 to more quickly identify and receive the synchronisation signals from neighbouring cells.

[0043] In one embodiment, UE1 may then notify the base station 212 that it can use an enhanced measurement gap pattern, which has a shortened MGL compared with the MGL of a legacy measurement gap as shown in Figure 3. The base station 212 may then assign an enhanced measurement gap pattern to UE1. The base station 212 and UE may store one or more enhanced measurement gap patterns that can be assigned to UEs. The one or more enhanced measurement gap patterns may be made based on the timing information from UE2 or with assistance / acknowledgement from UE2 so that at least one of the one or more enhanced measurement gap patterns has a measurement gap covering the time at which synchronisation signals are received at UE2. UE1 may request the base station 212 to assign a particular enhanced measurement gap pattern to UE1 or the base station 212 may select a pattern based on an indication from UE1 that an enhanced measurement gap pattern can be used.

[0044] In another embodiment, UE2 may send the timings of synchronisation signals received at UE2 to the base station 212. The base station 212 may then determine one or more measurement gap patterns with an optimum duration that covers the timings and assign the determined one or more measurement gap patterns to UE1. The base station may assign the measurement gap patterns to UE1 based on the proximity between UE1 and UE2, e.g. if UE1 is close enough to UE2 to receive signals via a D2D link with satisfactory quality, the base station may decide to assign the measurement gap patterns to UE1. Alternatively, UE1 may send the timings of synchronisation signals it received from UE2 to the base station 212 and the base station 212 can then determine and assign measurement gap patterns with an optimum duration to UE1. The duration may be the minimum duration that is required to cover the synchronisation signals from neighbouring cells within a single measurement period.

[0045] In another embodiment, the base station 212 has access to one or more predetermined measurement gap patterns, and UE2 is informed of the existing measurement gap pattern(s) by the base station 212. The UE2 may determine if UE2’s finding on the timing of receipt of synchronisation signals from a neighbouring cell matches any one of the existing measurement gap pattern(s), and may then inform the base station of the measurement gap pattern that matches, which may be then assigned by the base station 212 to UE1 and other UEs in the cell. In this way, the enhanced pattern can be assigned to multiple UEs, including UE1, within the proximity of UE2 with a minimum amount of signalling. The base station 212 may only assign the measurement gap pattern identified by UE2 to another UE in the cell if the distance between UE2 and the other UE is small enough, e.g. small enough for the other UE to receive signals via a D2D link with satisfactory quality from UE2.

[0046] UE2 may send the timing and/or frequency information of neighbouring cells to UE1 via a D2D link, or by any other suitable communication means known to the skilled person. For example, the information may be sent via the radio network.

[0047] In order for the information sent by UE2 to be effectively used by UE1, preferably some conditions are met. The following are some examples of such conditions: (1) neighbouring cells to be detected by both UEs are common or at least most of these neighbouring cells are common to the UEs; (2) |RTT(UE2)-RTT(UE1)| should be small enough for UE1 to rely on timing detected by UE2. In LTE, typically the distance for UE1 to reliably use the synchronisation information detected by UE2 for detecting synchronisation signals at UE 1 is up to 1 OFDM symbol (approximately 66 micro seconds); and (3) UE1 can receive signals from UE2 with satisfactory quality and reliability via a D2D link or otherwise.

[0048] In some cases, the information sent by UE2 may not be suitable for use by UE1, for example when these two UEs are too distant from each other such that the time at which the synchronisation signals from a neighbouring cell arrive at UE1 and UE2 is not substantially the same. In this case, UE1 cannot use the information on synchronisation signals sent by UE2, as the timing information would not allow UE1 to detect the synchronisation signals of the neighbouring cell as they would arrive at UE1 at a different time than expected.

[0049] UE1 may detect this situation when: (a) UE1 cannot receive D2D transmission / broadcast by UE2, and/or (b) the timing information sent by UE2 does not match UETs own findings (for example from previous measurement, or an inability to detect the signals at the indicated time). When UE1 detects any of these situations, UE1 may use a fallback mechanism, e.g. the legacy (conventional) measurement gap pattern assigned without prior knowledge from another UE.

[0050] Measurement gaps can be assigned by the network on request from UE1. Alternatively UE1 may not request the network to assign the measurement gap, but may attempt to detect the synchronisation signals at the timings acquired from UE2. In both scenarios, UE1 can benefit from reduced power consumption due to reduced need to hunt for the signals. In the scenario where the measurement gaps are assigned by the network based on the timing information, UE1 can benefit from improved available time for its data / signalling communication with its current serving cell due to shorter measurement gaps.

[0051] Figure 3 illustrates a shortened measurement gap length (MGL). The shortened measurement gap may have the minimum length that is required to cover all synchronisation signals within a single measurement period.

[0052] Conventionally, without the knowledge of the timing and frequency of neighbouring cells, a UE has to be assigned a measurement gap with a relatively long length 302 so that it can capture all synchronisation signals from neighbouring cells that are transmitted at arbitrary, unknown timings and/or frequencies. The MGL assigned in the conventional way, i.e. without UETs knowledge of timing and frequency information, is referred to as a legacy MGL, which may be longer than is necessary for detecting synchronisation signals from neighbouring cells.

[0053] In contrast, when the UE has obtained the timing and optionally frequency information of synchronisation signals from neighbouring cells, e.g. from a nearby UE, according to the embodiments, and transmitted that to the network, the UE can be assigned a measurement gap of a shortened length 304 that may be the minimum length required to capture signals from neighbouring cells.

[0054] Timings at which signals from different cells are sent may be different and discrete in time. It may not be an efficient use of the measurement gap if these discrete timings are assigned a single gap. In this case, the network can assign to a UE a flexible measurement gap pattern, which may comprise a plurality of discrete measurement gaps set within a longer measurement period, each gap corresponding to a timing of synchronisation signals from a particular cell. Then the signals from each neighbouring cell can be measured within one of the plurality of measurement gaps. The time between the measurement gaps can be used for data transmission.

[0055] Figure 4 is a flow chart showing a method according to one embodiment of the present invention.

[0056] In optional step 402, the base station 212 of a serving cell may detect two UEs, e.g. UE1 and UE2, within its signal coverage and with proximity to each other.

[0057] In step 404, one of the UEs, e.g. UE2, transmits / broadcasts a message comprising information indicating the timing and/or frequency of synchronisation signals of neighbouring cells of the serving cell. Such information may be a list of timings of the synchronisation signals, each time being for a neighbouring cell. The transmission or broadcast by UE2 may be through a D2D link, or any other suitable telecommunication methods or protocols. The transmission or broadcast of such information may be performed autonomously by UE2 or performed in response to a request from the base station 212 of the serving cell, a UE, or from any other server or device in the network, based on the detection of more than one UE in step 402.

[0058] In step 406, UE1 receives the information indicating the timing of synchronisation signals of neighbouring cells from UE2, via e.g. a D2D link.

[0059] Then in step 408, UE1 may inform the base station 212 of the serving cell of the timing information and may request assignment of an enhanced measurement gap pattern by the base station 212 of the serving cell or from any other server or device in the network capable of making such an assignment. Similarly, the UE1 may transmit the timing information without a specific request for an enhanced measurement gap and the network may decide whether to allocate one.

[0060] In step 410, the base station 212 of the serving cell or any other server or device capable of making such an assignment may assign the enhanced measurement gap pattern to UE1. The information indicating the timing of synchronisation signals may be used to determine the enhanced measurement gap pattern for use by UE1 in the detection of synchronisation signals of neighbouring cells. In some embodiments, the information may be used to determine the length of the measurement gap(s) and/or the starting point(s) of the measurement gap(s). The information may be used to determine a measurement gap with a shortened length, which may be the minimum duration required to cover the SSs of neighbouring cells in a measurement period, such as the shortened measurement gap described above with reference to Figure 3. The determination of the enhanced measurement gap pattern may be carried out by the base station 212 of the serving cell if the information on timing is received from UE1 and/or by any other server or device in the network.

[0061] As an alternative to steps 408 and 410, UE1 may determine the enhancement measurement gap pattern itself based on the received information indicating the timing of synchronisation signals of neighbouring cells. UE1 may then request assignment of a specific enhanced measurement gap pattern by the base station 212 of the serving cell or from any other server or device in the network capable of making such an assignment.

[0062] As an alternative to steps 404, 406 and 408, UE2 may transmit the information on timing directly to the network without transmitting the information to UE1, and the network may carry out the determination of the enhanced measurement gap pattern based on the information and assign the enhanced measurement gap pattern to UE1.

[0063] Optionally, a determination may be made on whether or not the information received in step 406 is suitable for use by UE1. The determination may be made based on e.g. the distance between UE1 and UE2; the value of RTT(UE1) - (RTT(UE1) -RTT(UE2)); and/or the mobility of UE1 and/or UE2. The received information may be determined to be suitable for use by UE1, e.g. if the distance between UE1 and UE2 is below a threshold value; the value of RTT(UE1) - (RTT(UE1) - RTT(UE2)) is larger than a threshold value or small enough to allow UE1 to receive signals from UE2 with satisfactory quality and reliability via a D2D link or otherwise; or the mobility of UE1 and/or UE2 is below a threshold value.

[0064] Such a determination may be made by UE1 itself. It may also be made by the base station 212 of the serving cell or by any other server or device in the network on request of UE1. UE 1 may make such a determination based on the quality of signals received from UE2 via a D2D link or otherwise. For example, if UE1 finds that the quality of signals received from UE2 via a D2D link or otherwise is not satisfactory, it may determine that the information received in step 406 is not suitable for its use. UE1 may also determine that the information received in step 406 is not suitable for its use when the information does not match UE1’s own findings.

[0065] If it is determined that the information is suitable for use by UE1, then the method proceeds from step 406 to 408 as described above.

[0066] However, if it is determined that the information is not suitable for use by UE1, the method proceeds from step 410 to step 412, in which UE1 may be allocated a legacy (default) measurement gap length and /or a legacy Measurement Gap Repetition Period (MGRP), i.e. one determined in a conventional way without the use of information received from another UE. In an alternative embodiment (not shown in Figure 4), the step of 412 may be carried out immediately after step 406. In this case, if in step 412 it is determined that the information is suitable for use by UE1, the method will proceed to step 408.

[0067] Compared with the legacy measurement gap allocation to a UE, the method according to embodiments of the present invention may provide some or all of the following effects.

[0068] Increased scheduling opportunity: By assigning a smaller gap duration towards a UE, the amount of time that may be used by the UE for data transfer is increased, and higher throughputs can be achieved from both the UEs and the network’s perspective. Furthermore, as more time is available for data transfer, the required scheduling effort from the network side is more relaxed.

[0069] Reduced power consumption: by receiving almost accurate synchronization info from another device in proximity, a UE would spend less time and resource in blind detection of synchronisation signals from neighbour cells, and the power consumption used for such detection can be reduced. Even if a UE has multiple radio units and does not require measurement gaps, power consumption can be reduced by using the method according to the embodiments.

[0070] Faster wake-up time from sleep/lonq Discontinuous Reception (DRXV After sleep mode/long DRX cycle (more than several seconds), the information a UE may keep on cell timing may not be valid due to drifts in the clocks during sleep time. By quickly detecting another UE in proximity and obtaining information on synchronisation signals of neighbouring cells from it, the UE can recover the timing of neighbour cells in less time [0071] The above embodiments are provided by way of example only. The disclosure of this application is not restricted by the specific combination of steps shown in the figures, and described herein, but includes any appropriate subsets or combinations of steps performed in any appropriate order. Sections of the method may be performed in parallel.

[0072] The term 'user equipment' (UE) is used herein to refer to any device with processing and telecommunication capability such that it can perform the methods and functions according to the embodiments of the present invention. Those skilled in the art will realize that such processing and telecommunication capabilities can be incorporated into many different devices and therefore the term 'user equipment' includes mobile telephones, personal digital assistants, PCs and many other devices.

[0073] The term ‘server’ may is used herein to refer to any device with processing and telecommunication capability such that it can interact with one or more UEs to perform the methods and functions according to the embodiments of the present invention. Those skilled in the art will realize that such processing and telecommunication capabilities can be incorporated into many different devices and therefore the term 'server' includes base stations (e.g. eNodeB) or any other devices which are configured to perform the methods and functions according to the embodiments of the present invention.

[0074] Although in the embodiments and examples given above, only two UEs are described, it will be appreciated that the number of UEs involved in the method may exceed two.

[0075] Although in the embodiments and examples described above, D2D is described as an exemplary communication methods for transmitting synchronisation signals from one UE to another, it will be appreciated that any other telecommunication methods can be used for such transmission.

[0076] In the embodiments and examples described above, information on the synchronisation signals of neighbouring cells are used to determine measurement gaps. However, even for a UE with multiple radio units and not requiring measurement gaps, receiving information on the synchronisation signals from another UE as described in the above methods would still help the UE take measurement of the synchronisation signals at the appropriate timings, leading to e.g. reduced power consumption.

[0077] Any range or device value given herein may be extended or altered without losing the effect sought, as will be apparent to the skilled person.

[0078] The skilled person may adapt the embodiments for use in any telecommunication network, such as 4G, 3G and 2G or with any other telecommunication standard without losing the effect sought.

[0079] It will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several embodiments. The embodiments are not limited to those that solve any or all of the stated problems or those that have any or all of the stated benefits and advantages.

[0080] Any reference to 'an' item refers to one or more of those items. The term 'comprising' is used herein to mean including the method blocks or elements identified, but that such blocks or elements do not comprise an exclusive list and a method or apparatus may contain additional blocks or elements.

[0081] The steps of the methods described herein may be carried out in any suitable order, or simultaneously where appropriate. Additionally, individual blocks may be deleted from any of the methods without departing from the spirit and scope of the subject matter described herein. Aspects of any of the examples described above may be combined with aspects of any of the other examples described to form further examples without losing the effect sought.

[0082] It will be understood that the above description of a preferred embodiment is given by way of example only and that various modifications may be made by those skilled in the art. Although various embodiments have been described above with a certain degree of particularity, or with reference to one or more individual embodiments, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the scope of this invention.

Claims

1. A method comprising: receiving, by a first User Equipment (UE) from a second UE, information on the time at which synchronisation signals are received at the second UE from one or more base stations to which the first and second UEs are not connected; and obtaining, by the first UE based on the received information, a timing pattern for detecting, by the first UE, synchronisation signals transmitted from the one or more base stations.

2. The method of claim 1, wherein said obtaining the timing pattern comprises obtaining, by the first UE, one or more measurement gap patterns for detecting synchronisation signals from the one or more base stations.

3. claim 2, wherein said obtaining one or more measurement gap patterns comprises sending, from the first UE to a serving base station, an indication that a predetermined enhanced measurement gap pattern is to be selected for use, and receiving, by the first UE from the serving base station, said enhanced measurement gap pattern for use by the first UE.

4. The method of claim 2, wherein said obtaining one or more measurement gap patterns comprises sending, from the first or the second UE to the serving base station, the information on the time at which synchronisation signals are received at the second UE from the one or more base stations, and receiving, by the first UE from the serving base station, an enhanced measurement gap pattern determined based on the information.

5. The method of any of claims 2-4, further comprising, if it is determined that the received information is suitable for use by the first UE for detection of synchronisation signals, detecting, by the first UE within the one or more measurement gap patterns, synchronisation signals transmitted from the one or more base stations.

6. The method of any of claims 2-4, further comprising if it is determined that the received information is not suitable for use by the first UE for detection of synchronisation signals, using, by the first UE, a legacy measurement gap pattern for detecting synchronisation signals from the one or more base stations.

7. The method of claim 2, wherein the first UE comprises a plurality of radio units, and the timing pattern is used by one of the radio units for detecting synchronisation signals from the one or more base stations.

8. The method of any preceding claim, further comprising receiving, by the first UE from the second UE, information on one or more frequencies at which synchronisation signals are transmitted from the one or more base stations to which the first and second UEs are not connected, and using, by the first UE, said information on one or more frequencies for detecting synchronisation signals transmitted from the one or more base stations.

9. A method for determining a timing pattern for use by a first User Equipment (UE) to detect signals in a telecommunication network, the method comprising: obtaining, by a second UE, the timings at which synchronisation signals are received at the second UE from one or more base stations to which the first and second UEs are not connected; transmitting, by the second UE, said timings to the first UE or a serving base station so that the timing information is available for use by the first UE or the serving base station to determine a timing pattern for detecting by the first UE synchronisation signals from the one or more base stations.

10. The method of any of claims 1-7 and 9, wherein the information is transmitted from the second UE to the first UE via a Device-to-Device (D2D) link.

11. A method for determining one or more measurement gap patterns for a first User Equipment (UE) in a telecommunication network, comprising receiving, by a base station, an indication that an enhanced measurement gap pattern can be assigned to the first UE or information on timings at which a second UE receives synchronisation signals from one or more base stations to which the first and second UEs are not connected; determining, by the base station, an enhanced measurement gap patterns to allow the first UE to detect the synchronisation signals, the determining being based on the received indication or the received information on timings, and assigning, by the base station, the determined one or more measurement gap patterns to the first UE.

12. The method of claim 11, further comprising determining, by the base station, if information on timings of receipt of synchronisation signals received by the first UE from the second UE is suitable for use by the first UE for detection of synchronisation signals, wherein the determining and assigning of one or more measurement gap patterns only occur if it is determined that they are suitable for such use.

13. The method of claim 12, wherein said determining if the information on timings of receipt of synchronisation signals is suitable for use by the first UE is made based on at least one of a distance between UE1 and UE2; a comparison of a Round-Trip Time (RTT) for UE1 and the difference between RTT for UE1 and RTT for UE2; and a mobility of UE1 and/or UE2.

14. A method comprising: receiving, by a first UE from a second UE, information on one or more frequencies at which synchronisation signals are transmitted from one or more base stations to which the first and second UEs are not connected, and using, by the first UE, said information on one or more frequencies for detecting synchronisation signals transmitted from the one or more base stations.

15. A method for facilitating signal detection by a first UE in a telecommunication network, the method comprising: obtaining, by a second UE, one or more frequencies at which synchronisation signals are received at the second UE from one or more base stations; transmitting, by the second UE to the first UE, information on said one or more frequencies so that it is available for use by the first UE for detecting synchronisation signals from the one or more base stations.

16. The method of claim 14 or 15, wherein the information is transmitted from the second UE to the first UE via a D2D link.

17. The method of any preceding claim, wherein the first UE and the second UE are connected to the same base station.

18. An apparatus, comprising means for performing the method of any of claims 1-8 and 14.

19. An apparatus, comprising means for performing the method of any of claims 9 and claim 15.

20. A base station, comprising means for performing the method of any of claims 11-13.