GB2508646A - Exchanging initial access content by way of radio resource control signalling for pre-configuring a user device with parameters useful for relaying purposes - Google Patents

Abstract

In a mobile radio communications network User Equipment (UE) device 8, so-called UE Target device, can successfully pursue an initial access procedure to a node (e.g. eNB) 2 of a Radio Access Network 4 but in a manner where such procedure is relayed by way of a further UE device 6 serving as a UE Relay. Initial access signaling content is delivered between the node 2 and the UEs 6, 8 so as to provide for pre-configuration of the further UE 6 as a UE relay, and between the UE Target device 8 and the UE Relay, within Radio Resource Control (RRC) messaging which can comprise enhanced current RRC messages, or specific new RRC messages. In either case the network node 2 can then communicate via the UE Relay 6 with a UE Target 8 which may not otherwise be under its coverage. Pre-configuration of UE 6 from the network allows detection of dedicated Random Access preamble of UE 8 at UE 6. Initial access content comprises information provided from UE 6 to UE 8 for said initial access procedure and comprises local information in the form of at least one of cell selection information frequency band/carrier signaling, RACH configuration parameters.

Description

Network Access The present invention relates to User Equipment (UE) network access procedures in a mobile radio communications network and system, and including signai relaying.

In a 3 Generation Partnership Project (3GPP) Long Term Evolution (LTE) network, the evolved NodeB (eNB) network nodes forming part of the Radio Access Network serve to transmit/receive data and signalhng between the Core Network (CN) and the UE devices which are under its radio cefl coverage. The UEs also transmit/receive data and/or signailing to/from the eNE whenever a communication session is required (e.g. to register, update registration, establish a data session or a voice cafi).

However, due to various factors, such as environmental characteristics, path loss, and power Umitation, the cell coverage may be Hmited or there may be some regions where the signals from the eNB cannot be decoded by the UEs. In addition, since an eNB serves as a focus for the communication signaUing, its available resources may become limited or insufficient. Consequently there may be fewer services avaflable for users and the ongoing communication/applications may suffer latency issues.

In an attempt to deal with some of the above problems and Umitations, discussions within 3GPP Groups have suggested the introduction of Relay Node entities in the form of Relay Base Stations. In such an arrangement, rather than having the UEs operating in direct communication with the eNB, data and/or signaHing from the UE for example passes via one of the Relay Nodes before reaching the target node generafly referred to as a Donor eNS or DeNS. Convers&y, for eNS to UE communication, transmitted data and/or signafling can pass through a Relay Node before reaching the UE.

Such a relaying function is considered attractive for improving the cell coverage and/or providing the network with offloading alternatives.

3GPP mobile standardization discussions have also covered aspects of tearhydevice" communication in the context of Public Safety scenarios as part of the Prose study started in 2011. In the context of pubc safety, the communication between nearby device is expected to allow the users to fulfill their mission even when there is a lack of network infrastructure coverage. The use of device as relay for other device is also expected in public safety situation, in order to extend the network coverage either at the edge of a cefl, or when a pubflc safety user is in a coverage hole inside a building and has to rely on nearby devices under coverage to access to the network infrastructure.

Also from WO 2011/111229, it is known to provide a mobile communication system with relay control and employing a relay station for reiayng communication signals between a base station and mobile station, but with operational imitations as to the manner of messaging between the stations and the relay configuration.

The invention seeks to provide for a network access rSay procedure and related systems and devices having advantages over known said procedures, systems and devices.

According to one aspect of the present invention, there is provided a method of enabling an initial access procedure for a first UE device to a node of a mobile radio communications network via a second UE device, and including the step of conveying initial access content by way of Radio Resource Control signaffing within the network.

The invention provides an advantageous mechanism whereby the network can communicate with a UE device, hereafter referred to as a Target UE or UET, by way of another UE device, hereafter referred to as a Relay UE or UER, wherein the UET need not be under the networks coverage, for initial access purposes. This can also provide control of the initial access parameters to the network.

While the MAC and Physical parameters needed for the UE-T RACH procedure could be conveyed into the UERs MAC and Physical parameters, this would lead to signalfing overheads for the relevant protocols, and the present invention does not exhibit such disadvantages and limitations. Also, through use of the RRC protocol according to an embodiment of the present invention, improved reliability of transmission of the RRC messages can be achieved and which would not arise with MAC nor PHY protolools.

The said Radio Resource Control signafling conveying the initial access content can be arranged for preconfiguring the second UE device as an UER device, and this can include the step of broadcasting initial access content from the second UE device to the flrst UE device.

it wW be appreciated that the initial access content is not restricted but can advantageously include at least part of System nformation Broadcast parameters.

As another option, rather than initial broadcast of the content, it can be stored in the said second UE for a subsequent initial access procedure in the said first UE.

In another embodiment of the invention, the initial access content comprises second UE device information provided from the second UE device to the first UE device for the said initial access procedure.

The said second UE device information can comprise local information in the form of at least one of ceU selection information, frequency hand/carrier signalling, and Further can be provided from the said second UE device along with information delivered from the network to the said first UE device.

Alternatively, the second UE device can be arranged to supersede received network broadcast information with the said local information prior to deHvery to the said second UE device.

Yet further, the initial access content can comprise first UE device initial access parameters, and provided within an additional Radio Resource Control message conveyed from the said second UE device to the network.

In particuier, the said initial access content can include MAC content.

In one example, the said initial access content can comprise a Radio Resource Controi message enhanced with an additional Information Element including the said content.

Alternatively, the said initial access content can comprise an additional Radio Resource Control message.

The method can be performed so that the said second UE device can handle the complete Random Access Channel procedure of the said first UE device, or alternatively so that the said second UE device relays at east part of a Random Access Channel procedure of the said first UE device to the network.

According to another aspect of the present invention, there is provided a mobile radio communications network UE device, arranged to receive initial access content by way of Radio Resource Control signailing within the network, for precontiguration as a UE-Relay device (UBR) for relaying initial access content between a UE-Target device (UB T) and the network.

According to yet another aspect of the present invention there is provided a mobile radio communication network UE-Target device (UET), arranged to exchange initial access content by way of radio resource control signafling with a UBRelay device (UE-R) within the network, for providing initial access of the UBTarget device (UET) to the network, As will be appreciated, a particular aspect of the invention focuses on the Random Access Channei (RACH) procedure and how to achieve this by way of a a UE-Relay device (UE-R).

From the more detailed discussion that follows, the invention can provide for new RRC (Radio Resource Control) Information Elements (lE), or indeed a new RRC message, allowing the RAN, via an eNE and dedicated signalling with information to be broadcast or stored, to configure the UER. The UER can then serve to relay a target UE's initial access procedure, such as its Random Access procedure: to the RAN.

Such new RRC signaDirig can also sHow a UE-R to broadcast initial access information as received from the RAN for relayed UEs; broadcast some initial access information that would supersede that of the RAN; and to transfer relayed UEs initial access related message/informaflon tolfrom the RAN's eNB, In this manner, a target UE can gain initial access to the network via the UE-R.

The invention is described further hereinafter, by way of example only, with reference to the accompanying drawings in which: Fig. I is a schematic representation of connections of mobile radio communication UE devices within a mobUe radio communications network according to an embodiment of the present invention: Fig.2 is a signaHing diagram illustrating an initial access procedure for UE within a E UTRAN environment and as known in the art; Fig. 3 is a signalling diagram relaU.ng to preconfiguration of a UER device according to one embodiment of the present invention; Fig. 4 is a signalling diagram relating to preconfiguration of a UER device according to another embodiment of the present invention; Fig. 5 is a diagram of signalling for configuration of a UER device in an embodiment of the present invention; and Fig. 6 is a diagram of signalling of a UE-R relaying initial access messaging in another aspect of the invention, Turning first to Fig.1, there is ilkistrated, in a schematic form, network connectivity according to an embodiment of the present invention but without reference to the Core Network (CN). Accordingly, there is illustrated a node 2 of a Radio Access Network (RAN) 4 and first and second mobile radio communication devices, such as User Equipment (UE) 6 and User Equipment (UE) 6. While UE 6 is under coverage of the RAN 4 for the initial access purposes, this need not be the case for UE 8. However, and as is described in further detail below according to one particular embodiment of the present invention, the UE 6 can be configured as a rSy device UE-R by which communication between the RAN 4 and the UE 6, which can then be identified as a target device UET, can be achieved as required.

By way of initial background however, reference is made to Fig. 2 which illustrates the messaging arising in an initial access procedure for a UE device within a E.UTRAN cell.

Fig. 2 is a schematic representation of a cellular network environment 10 of a mobile communications system in which a UE device 12, such as for example a mobile phone handset is to establish connection with a network node eNB 14 of the systems Radio Access Network (RAN), the full RAN and Core Network not being represented in the figure.

Within the network environment System Information Block (SIB) messaging 16 originates from the eNB 14 and can be received by UE12. Until such time as access by the UE 12 to the RAN is made, and the connection established, the RAN and its eNE 14 are unaware of the existence of the UE 12 within the cell. In order to start the connection between the UE 12 and the eNB 14 the UE 12 initiates a random access procedure by way of a Random Access Channel (RAC}-1) so that it becomes visible within the cell. The RACH procedure comprises Physical RACH (PRACH) preamble signalling 18 from the UE 12 and a random access response 20 from the eNB, The transmission of the preamble 18 is governed by a Preamble Transmission Counter and also generates a Random Access Radio Network Temporary Identifier (RA-RNTU. The PRACH preamble and "RA config" parameters are of course known by the UE 12. and the RA config' known for each PRACH-Configuration broadcast. The eNB 14 computes the RARNTI further to the preamble 18 reception and within the response 20 includes RA radio information such as a PA preamble identifier, temporary Ceft-RNTI, Uplink grant and Timing Advance parameters.

Once the RACH procedure represented by signalling 18. 20 have been completed. the UE 12 sends a Radio Resource Control (RRC) ConnectionRequest 22 to which the eND 14 responds with contention resolution signalling 24 and subsequently a RRC ConnectionSetup message 26, If the UE 12 detects successful completion of the PA procedure, the temporary nature of the C-RNTI is promoted to full CRNTl. If the detection of such success does not occur within a contention resolution timer range related to the signalling 24, the procedure returns to the RACH stage with the UE 12 sending a new PRACH preamble.

Confirmation that the initial access procedure has been succesafuily completed is sent by way of an appropriate confirmatorj message 26 from the UE 12.

The following discussion of particular embodiments of the present invention focus on the RACH procedure comprising messages 18 and 20 of the known initial access procedure of Fig. 2, so as to provide means for performing an appropriate RACH procedure for a UE employing a r&ayed connection to the RAN by way of a UER.

Turning now to Figs, 3 and 4, there are illustrated variants of preconfigurstion procedures for a UE-R from the RAN for the broadcast of information for the UET. Two implementations are illustrated regarding the local information that the UER can provide to the UE-T. In the example of Fig. 3 UER broadcast System Information Broadcast (SIB) requested by the eNB 32 in the signal 36 to the UET. In the alternative of Fig. 4 UER broadcast SIB requested by the eNB 32 in the signal 36 where some parameters included in the SIB are superseded by UER.

Turning first to Fig. 3, there is provided a schematic illustration of a network environment in which a UE to be configured as a relaying UE, UE-R 30, of the invention is located within the cell of eNB 32, and which UER 30 can further communicate with a target UE to be relayed, UEI' 34. The eNB 32 provides the minimum preconfiguration for relaying purpose to the UER upon e.g. knowing that UER has relaying capabilities and UER moves onto the cell, and so, in order to achieve this novel aspect of the invention in this example, sends a signal 36 comprising RRCPreConfigurationlnfoForRelayingPurpose or RRCConnectionReconfiguration orRRCHandoverCommand containing relayedUEContainerlnfoToBeBroadcast IE including SlBl or partial 8131, 8132 or partial 3182, other SlBs (e.g. 81310/11 related to warning notifications) and rnaximumlntersroadcastingEvents Periodidty. The SIBs noted are those that the eNS 32 requests that the UER 30 broadcast towards the UET 34.Also, the maximum periodicity parameter is that which the eNB 32 requests UER 34 to respect between two consecutive broadcasting events towards the JET 34.

Subsequently the UER 30 forwards SIBs 36 to the UE-T 34, and which can comprise the eNB's S lBs.

In this manner, UER 30 preconfiguration for UET initial access can be achieved, In Fig. 4, there is iflustrated a signalling procedure for UE-R 30 preconfiguration for UE-T 34 initi access achieved where some parameters included in the SIB requested by the eNB in signang 40 are superseded by UER 30. Similar preconfiguration signalling 40 to that of Fig. 3 is sent from the eNB 32 to the UER 30 and with the same SIBs and parameters of maximum perlodicity. In this case however, the subsequent signalling 42 from the UE-R 30 to the UBT 34 comprise SIBs including local access information and whereby, according to this example of the invention, the UE-R 30 has replaced RAN SIBs with SIBs local information to UE-T 34.

The following Table below illustrates 5161/2110/11 parameters which can be requested using RAN configuration to be broadcast by the UER and as illustrated in Figs. 3 and 4.

Certain of the parameters can be modified locally by the UER and as such supersede those values provided by RAN in the UE-T as discussed further below.

Possible Values Parameter name reason of use Descnpton from TS 3t331) $161 information ce!!AccessReiafedlr,fo - -identities, The Needed by UBT to have P/mn-I dent ity first listed PLMN- P/mn-aeneral information on Identity is the IdenfflyU primary PLMN at _____________ ce//Reserved ENUM ERATED Foroperator {reserved, Use notReserved) tkH'j'A a Code that is tcckThgAceaCode common for all the PLMNS listed ce//identity _________________,raliBarmd Atbqtnint'orr FNHMFIATFD -whether the UE is (aHowed.

aflowed to seiect notAllowed} or reselect tHs cefl n RRC the mode A flag to odicate whether the UE is cRowed to s&ect EN tiM ERATED or reselect other fn1raiF:eqResekction {cUowed.

ceUs or the same notAflowed) Radio Frequency carrier when the ceR a barred.

A minh-rium RSRP (power) Q-RxLevMin -vaue ce/ISeIectionjnfo requirement for the ceH selection !NTEGER.8 Value apphcable for the caD to define the p.%iax-maximum power value aRowed for transmssbn.

freqbandlndicator -. iNTEGER (1.64) Periodicty of the Si-message hi ENUM ERATEDff3, radio frames, si-Period/oily rf 16 rf32. rfB4, such that ffi rf128, rf256, rf512t scheduling/n tot/st -denotes 6 ratho for tiE-I to be ab to receive frame and so on 2 to 51813 information *** mapped to this TypeS, sib-Mappinginfo Systeminformetic &blype4sibType5.

n message. &btype6siblype7.

There is no sihType8sibType9, mapping siblypel OsibTypel informaflon of I &bType12v92O, 51B2; t a always &bTypel 3-v920, present in the spare5spare4, spare f:rst 3, spare2, Syatemnformatio sperel, ...} message bled in the schedthEnghfoLEs t st This fied is tdd**Config mandatory n case of UEJ is in TDD mode present for iDE) mode Common Si scheduHng window for cU sitA/ThdowLenpth Sis. Uffit in ENUMERATED{ms for UE able to correofi receive milVsecor:ds, 1 ms2, meb. maiD, q.i13 information where mel rnsi5. rns2O, rna4O} denotes I miffisecond and so on To provide an indication on systeminfoVa!ueTag whether the For UE**T to update INTEGER (0.31) __________ contentof 3162 jtoSIBl3infoatiQnJfly.cttaflfli to B9 has changed Indicates whether the cell suoports IMS emergency ims-EmergencySuppod-cQ bearer serces ENUMERATED F..wy.gc.ncy scenados usino 1MS for UEs in imed {true} service mode If absent, MS emergency caD is not supported by the reMark in the ceO for UEs n Umited servtce mode For adthtional ceO CeS&ectontnfo-o&ISelectionlnfo**vP2O selection criteria v920 81S2 information Poaible Values Panmeter name -reason of use Deecriptioi -from IS 3&331) Access dass BOCLEAN ac-BarringForEmergency barrLng for AC 10 If the random ao-Barringfnfo number drawn by ENUMERATED{pOO fQRtoccnfiure cc-the UE is lower than p05, p10. p15, p20, cc-SarringFac this value, access is p25, p30, p40,pSO, network accordirsq to BafcingFcxM tar allowed. Otherwise p60, p70, p75, p80, its current capability O-S!gnaiLng the access is p85, p90, O95} end according to UE-T barred.

confiouration eq. the cc--UWRED(s4 AC BarringForM BsrringTirn barring Brie value in s, s16, s32, s64.

0-Dale a seconds. e128, s256, s512} ac-B ning Access class BiT STRING For& ac/a/ barring for AC 11-(SiZE(S)) L ¶ rach*-ConfigCommon bcch-Config pooh-Con fig Set of parameters prach-Ccnfig chann&- _________________________ used ror the odsch-CcnflgComrnon ConfgComnion radioResourcaCon f/gO according pusch-Configcornrnon parameter values arnmon ________________________ procecure pucch-ConfigComrncn souncnngRS-UL-Con figcommon upi inkPowerControlCom Parameters used for mon transmission in UpL!Uik channes for data and contro messages Used to indicate the ARFCN appicahe for a dowrt!ink, NTEGER(O. .maxEA u!CarrierFrnq upHnk or b RFCN) directk,nai (TDD) E UTRA cerher frequency T.ransms&on bandwidth conñgurations, in ENUMERATED {n6, u!BwrJw/dth*-upink, va!ue nB n15, n25, .n50. n75, ftq!nfo corresponds toG nlOO} resource bbcka and so on Ths aows the spectrum emis&on Nmts to he configured ackiiliona!SpectrumErnissi according to oca NTEGER(1.32) reau!rements. 1 he parameter refers to a set of predefined requirement& UETjmersAndConstant& Set of timer vaues used dudng specific event eg. the pedod of time waiting for a RRCConnectionRe quest message SB 10 and SB 11 kiformatkin Pozsbk Vues (from Parameter name reason of use DcrlpSn masse geidentif ier- -Identifies the source and To orovide JET wth warnino type of ETWS notification riotfEc.aton rnessags BIT S RING (SIZE (16)) serialNurnher Identifies variations of an EThJS notification Provides security warning Type-OCTET STRING (SIZE information for the ETWS (2 notification Identifies the warning type of the ETWS primary warningSecurllyinio-nolification and provides OCTET STRNG (SIZE information on (50)) emergency user aEer and UE popup Identifies the alphabeticodLig and the dataCodingScheme-OCTET STRING (SIZE language appued 1)) varatons ol an ET\NS notification.

As noted, certain of the above parameters can be modified locaUy by the UER 30. For example, within the SIB1 information, the QRxLevMin parameter can be modified by UE-R for ag. interference mitigation purpose and the qRxLevMinOffset" parameter can be modified by the UER for e.g. interference mitigation purpose. The "p-Max" parameter can be modified by the UER for e.g. interference Umitation purpose, and the freqBandlndicator" can be modified by the UER in case of e.g. dedicated frequency band for relaying or interference mitation purposes.

Within the 61B2 information, the "uplinkPowercontrolCommon' parameter can be modified by the UE-R in case of e.g. interference mitigation purpose, the "u-CarrierFreq' parameter can be modified by the UE--R in case of e.g. dedicated UL frequency band for relaying or interference mitigation purpose. The "ui-Bandwidth" parameter can be modified by the UER in case of e.g. interference imitation purposes, as indeed can the "additionalSpectrumEmission parameter. Also, the "UETimersAndConstants" can be arranged for the UE-R to configure the timers and constants related to the RRC Connection(Re)Estabshment, constants related to physical layer synchronization.

From the above UER precoriiguration for WET initial access, two possibe options can be covered and determined by the capabilfty of the UER to hande the actual UET RACH or not.

According to the device implementation, the UE.R may be arranged to handle any UET initial access procedure a. similarly to initial access procedure handllng by the RAN, or alternatively to only transfer UET initial access procedure message to the RAN Other parameters can also to be considered such as: Delay to access to network, such as by taking UE-R to eI and WET to UER ranges into account or by data priority; Cell planning, such as by cell loads and capacities; and input information for the RAN to decide to configure UER to handle UET RACH or not.

A scenario in which the UER is itseft able to execute the full UBT RACH is discussed further with reference to Fig. 5 and which concerns a dedicated configuration to the UE R to handle fully the Random Access procedure.

In this scenario reference is again made to a UE-R 30, eNB 32 and UE-T 34, it being noted that the eNS will identify that UER can handle UET RACH. For this purpose, eNS provides all necessary configuration information to UE-R. Initial signalling 44 is sent from the eNS 32 and comprises RRcpreConfigurationlnfoRelayingPurpose or RRCConnectionReconfiguration or HandoverCommand including relayedUEContainerinfoDedicated IE with Relay C-RNTI values range'.

The UER 30 can store the dedicated information for further UET RACE-I, and, subsequent to RARNTI generation of the JET 34, the UE-R 30 receives PRACH preamble signalling 46 and aims to compute the RA-RNTI.

A Random Access Response message 48 is then sent from the UER 30 to the UE-T 34 and which can include RA radio info includes (RA preamble ID, temp CRNTi (one of the previously configured C-RNTi values), UL grant, TA). UL grant and TA are computed from channel quaty information between 2 UEs, by way of signaUing 50 and the same as in State of Art where UE-R performs eNB related actions.

As noted, it is considered that the RAN knows that the UER is able to handle initial access procedure La compute necessary parameters for Random Access procedure such as temporary CRNTl, Jpnk grant and Timing Advance. UET sends Random Access preambles to U&R based on SIB broadcast parameters received from UER (as shown in Hg. 2).

UER is configured by the eNB via new RRC messages (PreconfigurationForRelayingPurpose) or enhanced RRC messages (RRCconnectionReconfiguration or HandoverCommand (Le.

RRCConnectionReconfiguraflon including Mobffltycontroflnformatbn IE)) with m/ayed'JEContaTherinfoDedicated IE including R&ay C-RNTI values range which wfll be further used when US-I performs the RA procedure.

Those C-RNTI vaftes are dedicated C-RNTl values for relaying purpose configured by the network.

Next, a scenario in which the UER is not able to handle the fuU UE-T RACH procedure is discussed with, reference to Fig. 6.

in this scenario, it is considered a precondition that the UE-R 30 is connected to eNB 32.

The procedure commences with generation of a RA-RNTI at the US-I 34 and the sending by the US-I 34 of a PRACH Preamble message 52. As a novS feature of this example of the present invention, the UER 30 then sends a RRCRelayUEULlnfolransfer including relayedUEContainerlnfooedicated IE which contains PhyParams: UE-T physical parameters detected message 54 to the eNB 32 which in turn creates a US-T ID RRC context. The physical parameters can be US-I RA- ANTI or V.me and frequency parameters used further by the eNB to compute UET RA-RNTI or Preambles sent by US-I for PA procedure.

A "RRCConnectionReconfiguration (of. configuration of SRB used for relay purpose (out of scope))" message 56 is then sent to the UE-R 30, followed by another novel feature of this example of the invention comprising the RRcRelayUEDLinfoTransfer containing relayedUEContainerlntoDethoated IE in which MacParams are Radio Access Response containing UE..T RA radio info message 58. The RA radio info of this message includes at least RA preamble ID, temp CRNTI to be used by UET for further access.

A "Random Access Response' message 60 is then sent from the UE-R 3Oto the UET 34 and RRCConnectionRequest" signal 62 r&ayed as 62A, 628 via the UBR 30.

At reception of the Random Access preamble from the UET and as sent based on SIB parameters broadcast by UER, the random access message is transferred to the eNB in new RRC UpLink messages (RelayUEULlnfoTransfer) including new Es (reiayedUEcontainer!nfoDedioated).

The UBT radio identifier used for random access, i.e. the RARNTl, wiU be further decoded by the eNS within the new container and random access response parameters (e.g. UET temporary CRNTl for further RRC connected state) are generated and transferred by UE-R in new RRC downlink messages (RelayUEDLinfoTransfer) including new lEe (r&ayedUEGonfainernfoDedicated). The IE contains MAC parameters used for Random Access Response.

As wiU therefore be appreciated, the present invention can provide for parameters and messages related to UET initial access to be conveyed into RRC messages or container Information Elements (lEs), in one aspect they are related to Relay UE preconfiguration by the Network to allow for UE-T initial access.

RRC messages can be arranged to include new lEe made up of parameters used for relaying purpose provided by the network. Such Es can be RSayUEconteiner!rsfoDed!cated which can be retained at the UE-R for further UET initial access. Alternatively they can be embodied as RelayUEcontainerlnfoToBeBroadcasl messages which are broadcast to the UE.T by the UER.

In further detail of such examples, the RelayUEContainerIn1oTo8eBrnadcist IE can inchide part or whole of the System Information Broadcast parameters avaHable in the network. Also this Re/ayuEcontainermfoToBeBrnadcast IE can indude maximumlnterBroadcastingEventsPeriodicity information which is the maximum periodicity that eNB requests UER to respect between two consecutive broadcasting events towards UET. The R&ayUEconbiTher!nfofledicated IE can include CeO Radio Network Temporary Identifier (CRNTI) values range for r&aying purpose. A new RRC message; such as RRCPreconfigurationlnfoForRelaying, or an existing RRC message, such as RRCConnectionReconfiguration, can be used to convey the RelayuEContainernfoDedicated IE or the RelayuEcontainer/nfoToBeBroadcaat IE.

In a further aspect they are related to UE-R information provided by UE-R to UET for initial access. Here the UER can provide local information such as ceO selection informaUon, frequency band/carrier via broadcast signalling to the UE-T. Beforehand the RAN can configure the type of information such as ceO selection information, frequency band/carrier that UE-R should set and provide to UE-T. In one arrangement, if the UE-R provides such information along with that received from RAN to UE-T, then such information can supersede that provided by the RAN in the UE-T. Alternatively the UE-R can supersede received RAN broadcast information with aforementioned information.

In yet a further aspect, the parameters and messages can be related to UE-T initial access. The R&ayUEconta!nerinfoDed/cated IE can include physical and MAC parameters related to UE-T initial access. In one example, a new RRC message, such as RRCRelayUEuLlnfoTransfer in which the UER includes UET initiai access parameters, is conveyed from the UE-R to the RAN. Also, a new RRC message, such as RRCRelayUEoLlnfoTransfer in which RAN includes MAC Random Access Response or MAC parameters is conveyed from the RAN to the UER. The latter serves to retrieve and forward the MAC Random Access Response to the UET and the UE-R can retrieve and build MAC message for the UEJ including the MAC parameters received from the RAN.

It should therefore be appreciated that the invention provides for a mechanism within a mobile radio communications network whereby a User Equipment (UE) device, so-called UET device, can successfuUy pursue an initial access procedure to a node of the network but in a manner where such procedure is reiayed by way of a further UE device serving as a UE-R. nitia access signafling content is deEivered between the node and the UEs so as to provide for preconfiguration of the further UE as a UER, and between the UETt device and the UER-, within Radio Resource Contrd (RRC) messaging which can comprise enhanced current RRC messages, or specific new RRC messages. ft' either case the network node can then communcate via the UE*-R with a UET which may not otherwise be under its coverage.

Claims (30)

1. Claims 1 A method of enabng an initial access procedure for a first LIE device to a node of a mobfle radio communications network via a second UE device, and including the step of conveying inial access content by way of Radio Resource Control &gnang within the network.
2. 2. A method as claimed in Cairn 1, wherein the said Radio Resource Control signafling conveying the initial access content is arranged for preconfiguring the second UE device with parameters useful for relaying purposes.
3. 3. A method as daimed in Claim 2, and induding the step of broadcasting initial access content from the second UE device to the first UE device.
4. 4. A method as claimed in a Claim 3, wherein the initiai access content includes at least System Information Broadcast parameters.
5. 5. A method as claimed in Claim 3 cr4, wherein the initial access content includes periodicity information from the node to the second LIE device for discerning between broadcast events towards the irst UE device.
6. 6. A method as claimed in Claim 2 or 3, and including the step of storing initial access content in the said second UE for a subsequent initial access procedure in the said first UE.
7. 7. A method as claimed in Claim 6, wherein the initial access content includes Cell Radio Network Temporary Identifier values.
8. 8. A method as claimed in any one or more of Claims 2 -7. wherein the said second UE device pm-configuration from the network allows at least detection of dedicated Random-Access preambles of the first UE device at the said second UE device.
9. 9. A method as claimed in any one or more of the preceding claims, wherein the initial access content comprises information from second WE device provided from the second UE device to the first UE device for the said initial access procedure.
10. 10. A method as claimed in Claim 9, wheSn the said second UE device information comprises local information in the form of at least one of cefl selection information, frequency band/carrier signalling, RACH configuration parameters.
11. 11. A method as daimed in Claim 10, wherein the said local inlormation is requested to be configured from second UE device by the node for first WE device said initia access.
12. 12. A method as claimed in Claim 10, wherein the said local information is provided from the said second UE device along with information dSvered from the network to the said first UE device.
13. 13. A method as claimed in Ciaim 10, wherein the second UE device supersedes received network broadcast information with the said local information prior to delivery to the said first WE device.
14. 14. A method as claimed in any one or more of the preceding claims, wherein the initial access content comprises first UE device initial access parame(ers.
15. 15. A method as daimed in Claim 14, wherein the initial access content is provided within an additional Radio Resource Control message conveyed from the said second UE device to the network.
16. 16. A method as daimed in Claim 15. wherein the said initial access content includes MAC content.
17. 17. A method as claimed in Claim 14, wherein the said initial access content includes MAC content delivered from the network to the said second WE device.
18. 18. A method as daimed in Claim 17, wherein the said MAC content comprises at east one of MAC random access response messaging or MAC parameters.
19. 19. A method as claimed in any one or more of Claims 1518, and including the step of the said second UE device forming a MAC message to the said first UE device and including MAC parameters received from the network.
20. 20. A method as claimed in any one or more of the preceding claims, wherein said initial access content comprises a Radio Resource Control message enhanced with an additional Information Element including the said content.
21. 21. A method as claimed in any one or more of Claims 1-19, wherein the said infflai access content comprises an additionai Radio Resource Controi message.
22. 22. A method as daRted in any one or more of the preceding daims, wherein the said initial access content comprises initial access parameters and messages.
23. 23. A method as claimed in Claim 22, wherein the said inifial access content comprises at east MAC and PHY parameters.
24. 24. A method as claimed in Claim 22 where PHY parameters comprise time and frequency parameters used to compute the Random Access -Radio Network Temporary Identifier (RA-RNTl) or a Preamble.
25. 25. A method as claimed in any one or more of the preceding claims wherein the said second UE device handles the complete Random Access Channel procedure of the said first UE device on behalf of the network.
26. 26. A method as claimed in Claim 25, wherein the said second UE device performs dedicated configuration for initial access handling of the said first UE device Random Access Channel procedure.
27. 27. A method as claimed in any one or more of Claims V24, and induding the step of, in the said second liE device, reaying at east part of a Random Access Chann& procedure of the said first UE device to the network.
28. 28, A mobe radio communications network liE device, arranged to receive initial access content by way of Radio Resource Control signalling within the network.for preconfiguration with parameters useful for relaying purposes for relaying initial access content between a second UE device and the network.
29. 29. A mobe radio communication network liE device, arranged to exchange initial access content by way of radio resource control signalfing with the network, for providing initial access of the mobfle radio communication liE device to the network.
30. 30. A method of enabling an initial access procedure for a first UE device to a node of a mobile radio communications network via a second UE device, substantiafly as he had before described with reference to, and is illustrated in, Figs 2, 3 4 and 5 of the accompanying drawings.