Method, apparatus and computer program relating to sending of messages for random access procedure

Abstract

A user equipment, comprising means for: in the event of receiving a response 404 to an instance of sending a first message 402 of a random access procedure, determining a transmission power for sendin

Description

TECHNICAL FIELD Various example embodiments of this disclosure relate to a method, apparatus and computer program and in particular but not exclusively to sending of messages for random access procedure. BACKGROUND A radio access network may, for example, enable communications between two or more user equipments, and / or enable the transfer of data between one or more user equipments and one or more data networks. The establishment of a wireless connection of a user equipment to a radio access network may involve a random access procedure, and the sending by the user equipment of messages of the random access procedure. SUMMARY Some example embodiments of this disclosure will be described with respect to certain aspects. These aspects are not intended to indicate key or essential features of the embodiments of this disclosure, nor are they intended to be used to limit the scope of thereof. Other features, aspects, and elements will be readily apparent to a person skilled in the art in view of this disclosure. A method, comprising: in the event of receiving a response to an instance of sending a first message of a random access procedure, determining at a user equipment a transmission power for sending a second message of the random access procedure, wherein the determining of the transmission power for sending the second message is partly based on a quantity having a value dependent on whether or not the instance of sending the first message comprises transmission repetitions; and after receiving a response to the sending of the second message, determining at the user equipment a transmission power for sending a third message also based at least partly on the quantity. A user equipment, comprising means for: in the event of receiving a response to an instance of sending a first message of a random access procedure, determining a transmission power for sending a second message of the random access procedure, wherein the determining of the transmission power for sending the second message is partly based on a quantity having a value dependent on whether or not the instance of sending the first message comprises transmission repetitions; and after receiving a response to the sending of the second message, determining a transmission power for sending a third message also based at least partly on the quantity. A user equipment comprising at least one processor; and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the user equipment to perform: in the event of receiving a response to an instance of sending a first message of a random access procedure, determining a transmission power for sending a second message of the random access procedure, wherein the determining of the transmission power for sending the second message is partly based on a quantity having a value dependent on whether or not the instance of sending the first message comprises transmission repetitions; and after receiving a response to the sending of the second message, determining a transmission power for sending a third message also based at least partly on the quantity. A user equipment comprising: determining circuitry for, in the event of receiving a response to an instance of sending a first message of a random access procedure, determining a transmission power for sending a second message of the random access procedure, wherein the determining of the transmission power for sending the second message is partly based on a quantity having a value dependent on whether or not the instance of sending the first message comprises transmission repetitions; and determining circuitry for, after receiving a response to the sending of the second message, determining a transmission power for sending a third message also based at least partly on the quantity. A computer readable medium comprising program instructions stored thereon for performing: in the event of a receiving a response to an instance of sending a first message of a random access procedure, determining at a user equipment a transmission power for sending a second message of the random access procedure, wherein the determining of the transmission power for sending the second message is partly based on a quantity having a value dependent on whether or not the instance of sending the first message comprises transmission repetitions; and, after receiving a response to the sending of the second message, determining at the user equipment a transmission power for sending a third message also based at least partly on the quantity. A non-transitory computer readable medium comprising program instructions stored thereon for performing: in the event of receiving a response to an instance of sending a first message of a random access procedure, determining at a user equipment a transmission power for sending a second message of the random access procedure, wherein the determining of the transmission power for sending the second message is partly based on a quantity having a value dependent on whether or not the instance of sending the first message comprises transmission repetitions; and after receiving a response to the sending of the second message, determining at the user equipment a transmission power for sending a third message also based at least partly on the quantity. A computer program comprising computer executable code which when run on at least one processor is configured to cause an apparatus at least to: in the event of receiving a response to an instance of sending a first message of a random access procedure, determine at a user equipment a transmission power for sending a second message of the random access procedure, wherein the determining of the transmission power for sending the second message is partly based on a quantity having a value dependent on whether or not the instance of sending the first message comprises transmission repetitions; and after receiving a response to the sending of the second message, determine at the user equipment a transmission power for sending a third message also based at least partly on the quantity. The quantity may be based at least partly on a factor having a value dependent on a number of transmission repetitions for the instance of sending the first message. The number of transmission repetitions may be the actual number of transmission repetitions made by the user equipment for the instance of the sending of the first message. The number of transmission repetitions may be a configured number of transmission repetitions determined by the user equipment for the instance of the sending of the first message, irrespective of whether one or more of the transmission repetitions are not made the user equipment. The quantity may be based at least partly on a factor having a value configured at a layer above the medium access control layer. The quantity may be based at least partly on a factor having a value based on an indication from the radio access network. The indication may be provided by a random access response message of the random access procedure. The indication may be provided by downlink control information from the radio access network. The quantity may be based at least partly on a factor having a value independent of a number of transmission repetitions for the instance of sending the first message. The quantity may be incorporated into a formula for calculating the transmission power for sending the second message and for calculating the transmission power for sending the third message. The quantity may be a function of at least a power ramping parameter, and the power ramping parameter may be a function of at least a factor having a value dependent on a number of transmission repetitions for the instance of sending the first message. The quantity may comprise a sum of at least a power ramping parameter and a factor having a value dependent on a number of transmission repetitions for the instance of sending the first message. The quantity may comprise a power control adjustment state for a formula determining transmission power. A method, comprising: sending by a radio access network node to a user equipment an indication of a value of a factor for use by the user equipment as at least part basis for determining a quantity for determining transmission power for sending further messages of a random access procedure in the event of the user equipment receiving a response to an instance of sending a first message of the random access procedure, wherein the use by the user equipment of the value of the factor is dependent on whether or not the instance of sending the first message comprises transmission repetitions. A radio access network node, comprising means for: sending to a user equipment an indication of a value of a factor for use by the user equipment as at least part basis for determining a quantity for determining transmission power for sending further messages of a random access procedure in the event of the user equipment receiving a response to an instance of sending a first message of the random access procedure, wherein the use by the user equipment of the value of the factor is dependent on whether or not the instance of sending the first message comprises transmission repetitions. A radio access network node comprising: at least one processor; and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the radio access network node to perform: sending to a user equipment an indication of a value of a factor for use by the user equipment as at least part basis for determining a quantity for determining transmission power for sending further messages of a random access procedure in the event of the user equipment receiving a response to an instance of sending a first message of the random access procedure, wherein the use by the user equipment of the value of the factor is dependent on whether or not the instance of sending the first message comprises transmission repetitions. A radio access network node comprising: sending circuitry for sending to a user equipment an indication of a value of a factor for use by the user equipment as at least part basis for determining a quantity for determining transmission power for sending further messages of a random access procedure in the event of the user equipment receiving a response to an instance of sending a first message of the random access procedure, wherein the use by the user equipment of the value of the factor is dependent on whether or not the instance of sending the first message comprises transmission repetitions. A non-transitory computer readable medium comprising program instructions stored thereon for performing: sending by a radio access network node to a user equipment an indication of a value of a factor for use by the user equipment as at least part basis for determining a quantity for determining transmission power for sending further messages of a random access procedure in the event of the user equipment receiving a response to an instance of sending a first message of the random access procedure, wherein the use by the user equipment of the value of the factor is dependent on whether or not the instance of sending the first message comprises transmission repetitions. A computer readable medium comprising program instructions stored thereon for performing: sending by a radio access network node to a user equipment an indication of a value of a factor for use by the user equipment as at least part basis for determining a quantity for determining transmission power for sending further messages of a random access procedure in the event of the user equipment receiving a response to an instance of sending a first message of the random access procedure, wherein the use by the user equipment of the value of the factor is dependent on whether or not the instance of sending the first message comprises transmission repetitions. A computer program comprising computer executable code which when run on at least one processor is configured to cause a radio access network node at least to: send to a user equipment an indication of a value of a factor for use by the user equipment as at least part basis for determining a quantity for determining transmission power for sending further messages of a random access procedure in the event of the user equipment receiving a response to an instance of sending a first message of the random access procedure, wherein the use by the user equipment of the value of the factor is dependent on whether or not the instance of sending the first message comprises transmission repetitions. The quantity may comprise a power control adjustment state for a formula determining transmission power for the further messages of the random access procedure. The value may be selected at the radio access network node from one of a plurality of candidate values for the factor. A method, comprising: performing at least one instance of a first sending of a first message of a random access procedure, wherein the first sending comprises no transmission repetitions or a first number of transmission repetitions; failing to receive a response to the first sending of the first message; performing at least one instance of a second sending of the first message of the random access procedure, wherein the second sending comprises a second number of transmission repetitions; in the event of receiving a response to the second sending of the first message after a first amount of transmission power ramping, sending a second message of the random access procedure at a transmission power determined based partly on the first amount of transmission power ramping. User equipment comprising means for: performing at least one instance of a first sending of a first message of a random access procedure, wherein the first sending comprises no transmission repetitions or a first number of transmission repetitions; in the event of failing to receive a response to the first sending of the first message, performing at least one instance of a second sending of the first message of the random access procedure, wherein the second sending comprises a second number of transmission repetitions; in the event of receiving a response to the second sending of the first message after a first amount of transmission power ramping, sending a second message of the random access procedure at a transmission power determined based partly on the first amount of transmission power ramping. User equipment comprising: at least one processor; and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the user equipment to perform: performing at least one instance of a first sending of a first message of a random access procedure, wherein the first sending comprises no transmission repetitions or a first number of transmission repetitions; in the event of failing to receive a response to the first sending of the first message, performing at least one instance of a second sending of the first message of the random access procedure, wherein the second sending comprises a second number of transmission repetitions; and in the event of receiving a response to the second sending of the first message after a first amount of transmission power ramping, sending a second message of the random access procedure at a transmission power determined based partly on the first amount of transmission power ramping. User equipment comprising circuitry for: performing at least one instance of a first sending of a first message of a random access procedure, wherein the first sending comprises no transmission repetitions or a first number of transmission repetitions; in the event of failing to receive a response to the first sending of the first message, performing at least one instance of a second sending of the first message of the random access procedure, wherein the second sending comprises a second number of transmission repetitions; and in the event of receiving a response to the second sending of the first message after a first amount of transmission power ramping, sending a second message of the random access procedure at a transmission power determined based partly on the first amount of transmission power ramping. A computer readable medium comprising program instructions stored thereon for performing: performing at least one instance of a first sending of a first message of a random access procedure, wherein the first sending comprises no transmission repetitions or a first number of transmission repetitions; in the event of failing to receive a response to the first sending of the first message, performing at least one instance of a second sending of the first message of the random access procedure, wherein the second sending comprises a second number of transmission repetitions; and in the event of receiving a response to the second sending of the first message after a first amount of transmission power ramping, sending a second message of the random access procedure at a transmission power determined based partly on the first amount of transmission power ramping. A non-transitory computer readable medium comprising program instructions stored thereon for performing: performing at least one instance of a first sending of a first message of a random access procedure, wherein the first sending comprises no transmission repetitions or a first number of transmission repetitions; in the event of failing to receive a response to the first sending of the first message, performing at least one instance of a second sending of the first message of the random access procedure, wherein the second sending comprises a second number of transmission repetitions; and in the event of receiving a response to the second sending of the first message after a first amount of transmission power ramping, sending a second message of the random access procedure at a transmission power determined based partly on the first amount of transmission power ramping. A computer program comprising computer executable code which when run on at least one processor is configured to cause a user equipment at least to: perform at least one instance of a first sending of a first message of a random access procedure, wherein the first sending comprises no transmission repetitions or a first number of transmission repetitions; in the event of failing to receive a response to the first sending of the first message, perform at least one instance of a second sending of the first message of the random access procedure, wherein the second sending comprises a second number of transmission repetitions; and in the event of receiving a response to the second sending of the first message after a first amount of transmission power ramping, send a second message of the random access procedure at a transmission power determined based partly on the first amount of transmission power ramping. The at least one instance of the first sending of the first message may comprise no transmission repetitions. The at least one instance of the first sending of the first message may comprise the first number of transmission repetitions, and the second number of transmission repetitions may be higher than the first number of transmission repetitions. The at least one instance of the first sending of the first message may comprise a second amount of transmission power ramping higher than the first amount of transmission power ramping for the at least one instance of the second sending. Performing the at least one instance of the first sending may comprise performing a first number of transmission power ramps; and performing the at least one instance of the second sending of the first message may comprise performing a second number of transmission power ramps; and the sending of the second message may be performed at a transmission power determined based partly on the second number of transmission power ramps. DESCRIPTION OF DRAWINGS Some example embodiments will now be described, by way of non-limiting and illustrative example only, with reference to the accompanying drawings in which: Fig, 1 shows a representation of an example of a communication system; Fig. 2 shows a representation of an example of apparatus for implementing one or more network functions of the communication system; Fig. 3 shows a representation of an example of user equipment according to some example embodiments; Fig. 4 shows a representation of an example of operations at a user equipment according to some example embodiments; Fig. 5 shows a representation of an example of operations at gNB according to some example embodiments; Fig. 6 shows a representation of another example of operations at a user equipment according to some example embodiments; and Fig. 7 shows a representation of an example of messages of a random access procedure. DETAILED DESCRIPTION In the following, various example embodiments are explained for the example of a user equipment operating according to a 3GPP 5th generation (5G) communication protocol, but the example embodiments may also be applicable to user equipments operating according to other communication protocols. In the following, various example embodiments are explained for the example of one type of random access procedure used for a 5G new radio (NR) access network, but the embodiments may also be applicable to other types of random access procedures. Fig. 1 shows a schematic representation of a 5G communication system (5GS). The 5GS may comprise a user equipment (UE), an access network such as a 5G radio access network (5G-RAN) or next generation radio access network (NG-RAN), a 5G core network (5GC), and one or more application functions. An application function may be deployed in the 5GS as trusted application function or may be deployed or host on one or more application servers of the data network. Such application functions are untrusted application functions. The 5GS connects the UE to a data network the access network and the 5GC (e.g., a UPF of the 5GC). The 5G-RAN may comprise one or more radio access nodes, such as gNodeB (GNB). A gNB may include one or more gNodeB (GNB) distributed units connected to one or more gNodeB (GNB) centralized units . The 5GC may comprise the following network functions: Network Slice Selection Function (NSSF); Network Exposure Function; Network Repository Function (NRF); Policy Control Function (PCF); Unified Data Management (UDM); Application Function (AF); Authentication Server Function (AUSF); an Access and Mobility Management Function (AMF); and Session Management Function (SMF), and a user plane function (UPF). Fig. 1 also shows the various interfaces (N1, N2 etc.) that may be implemented between the various elements of the system. Figure 2 illustrates an example of a control apparatus 200 for implementing an instance of a function of the radio access network such as the gNB in Figure 1. The control apparatus 200 may comprise at least one random access memory (RAM) 211a, at least on read only memory (ROM) 211b, at least one processor 212, 213 and an input / output network interface 214. The at least one processor 212, 213 may be coupled to the RAM 211a and the ROM 211b. The at least one processor212, 213 may be configured to execute an appropriate software code 215. The Execution of the software code 215 may for example allow to perform one or more steps may cause the apparatus to perform one or more of the present aspects operations for implementing an instance function of the access network. The software code 215 may be stored in the ROM 211b. The control apparatus 200 may be interconnected with another control apparatus 200 for implementing one or more instances of other functions of the access network or core network. Fig. 3 illustrates an example of a communication device 300, such as the user equipment (UE) illustrated in Fig. 1 and mentioned in the description of example embodiments below. The communication device 300 may be provided by any device capable of sending and receiving radio signals. Non-limiting examples of a communication device 300 comprise a user equipment, a mobile station (MS) or mobile device such as a mobile phone or what is known as a ’smart phone’, a computer provided with a wireless interface card or other wireless interface facility (e.g., USB dongle), a personal data assistant (PDA) or a tablet provided with wireless communication capabilities, a machine-type communications (MTC) device, an Internet of things (loT) type communication device or any combinations of these or the like. The communication device 300 may comprise a transceiver for transmitting and / or receiving, for example, wireless signals carrying communications, for example radio signals. The communications may be one or more of voice, electronic mail (email), text messages, multimedia data, machine data and so on. The communication device 300 may receive wireless signals (e.g., radio signals) over an air or radio interface 307 via appropriate apparatus for receiving and may transmit wireless signals via appropriate apparatus for transmitting radio signals. In Fig. 3 transceiver is designated schematically by block 306. The transceiver 306 may comprise, for example, a radio part and associated antenna arrangement. The antenna arrangement may be arranged internally or externally to the mobile device and may comprise one or more antenna elements. The antenna arrangement may be a multi-input multi output (MIMO) antenna. The communication device 300 may be provided with at least one processor 301, at least one memory ROM 302a, at least one RAM 302b and other possible components 303 for use in software and hardware aided execution of tasks it is designed to perform, including control of access to and communications with access networks (e.g., the 5G-RAN or NG-RAN illustrated in Fig. 1) and other communication devices. The at least one processor 201 is coupled to the RAM 302b and the ROM 302a. The at least one processor 301 may be configured to execute an appropriate software code 308. The software code 308 may for example allow to perform one or more operations of the communication device. The software code 308 may be stored in the ROM 302a. The processor, the ROM, and the RAM, the transceiver and other circuitry of the communication device (e.g., a modem) can be provided on a circuit board, in chipsets, or in a system on chip. The circuit board, chipsets or system on chip is denoted by reference 304. The communication device 300 may optionally have a user interface such as key pad 305, touch sensitive screen or pad, combinations thereof or the like. Optionally one or more of a display, a speaker and a microphone may be provided depending on the type of communication device. It is understood that references in the above to various network functions (e.g., to an AMF, an SMF, TNF etc.) may comprise apparatus that perform at least some of the functionality associated with those network functions. Further, an apparatus comprising a network function may comprise a virtual network function instance of that network function. It should be understood that the apparatuses may comprise or be coupled to other units or modules etc., such as radio parts or radio heads, used in or for transmission and / or reception. Although the apparatuses have been described as one entity, different modules and memory may be implemented in one or more physical or logical entities. Fig. 7 shows a representation of an example of a contention based random access (CBRA) procedure (referred to as 4-step RACH). As mentioned above, the techniques described herein may also be applicable to other random access procedures such as the contention free random access procedure (CFRA) and to any combination of 2-step RACH / 4-step RACH with CBRA / CFRA. With reference to Fig. 7, the 4-step RACH procedure comprises the following operations. UE sends a specific preamble (Msg1 (also referred to as PRACH)) to gNB of the NR via a physical random-access channel (PRACH) using a specific resource called RACH occasion or PRACH occasion (RO). gNB replies with a random-access response (RAR) message (also referred to as Msg2), which includes the detected preamble ID, a time-advance command, a temporary C-RNTI (Cell Radio Network Temporary Identifier), and an uplink (UL) grant for the transmission of Msg3 by UE via a physical uplink shared channel (PUSCH). UE responds to Msg2 by sending Msg3 (also referred to as radio resource control (RRC) request) over the scheduled PUSCH with an ID for contention resolution. gNB transmits the contention resolution message (Msg4 also referred to as RRC setup) with the contention-resolution ID. Upon reception of Msg4, UE sends an acknowledgment (ACK) on a physical uplink control channel (PUCCH) if the contention-resolution ID for the UE is carried by the received Msg4. The radio access network schedules UE to send an RRC setup complete message (referred to as Msg5). After Msg5 is received, the radio access network sends a message (not shown) for UE capability enquiry, and UE responds with UE capability information reporting. The radio access network then performs the first RRC reconfiguration according to the received UE capability information. Prior to Msg1, there may also be a preliminary step of sending and receiving the synchronization signal block (SSB), also referred to as downlink (DL) beam sweeping, This preliminary step involves the UE selecting the index of the preferred SSB beam and decoding the associated physical broadcast channel (PBCH) for the master information block (MIB) and system information blocks (SIB). This index is also used by UE to identify a suitable RO for the preamble transmission (Msg1), according to the SSB-to-RO mapping implicitly conveyed by system information block 1 (SIB1). A single instance of sending Msg1 may comprise transmission repetitions of Msg1, and an unsuccessful instance of sending Msg1 (no detection at UE of Msg2 in response to Msg1, e.g. no Msg2 transmitted by a network in response to Msg1 since Msg1 was not detected) may be followed by another instance of sending Msg1 (re-sending of Msg1) with power ramping of the transmission power, and / or the use of a larger number of transmission repetitions, aimed at increasing the probability of successful detection of Msg1 at the gNB receiver. Transmission repetitions of Msg1 may also be referred to as PRACH repetitions or multiple PRACH transmissions. As mentioned above, the techniques described herein may also be applicable to a 2-step random access procedure (in addition to the 4-step random access described above) involving transmission repetitions for sending of MsgA of the 2-step random access procedure or transmission repetitions for sending the preamble part of MsgA of the 2-step random access procedure. According to an example embodiment, UE calculates transmission power for sending of Msg3 and Msg5 as a function of a quantity incorporating a scaling factor y in the event that a successful instance of sending of Msg1 comprises transmission repetitions of Msg1. According to an example embodiment, uplink power control for the PUSCH channel for the sending of Msg3 and Msg 5 is calculated according to the following formula specifed in TS 38.213 for transmission of a PUSCH on active UL bandwidth part (BWP) b of carrier f of serving cell c using parameter set configuration with index j and PUSCH power control adjustment state with index I, in PUSCH transmission occasion (TO) i: / cMAX, / ,c(0? nilll ^PUSCH / -. , . . ... ,- ,. ,. / oPUSCH^. / c(J) + 101og10(2" -M™*™ ( / )) + abfc (J) • PLb f c (q„) + ATRi / c(i) + fb^c [dBm] Where (definitions are taken from TS 38.213): • ^uscha / xO') is a parameter composed of the sum of a component o_nominal,pusch,ycO) and a component P0_uE_puscH,t>,f,cC / ). with o j = 0, for a Msg3 PUSCH (re)transmission, and Po_UE_puscHAf,e(0) = °> and Po_nominal,pusch,y,c(0) = / ’o-Pre + ^preamble,Msg3, where Po_PRE is provided by preambleReceivedTargetPower and ^preamble ms93 is provided by higher-layer parameters msg3-DeltaPreamble or deltaPreamble, or APREAMBLEjMsg3= 0 dB if msg3-DeltaPreamble and deltaPreamble are not provided, on active UL BWP b of carrier f of serving cell c • ab,f,c(J) is equal to higher-layer parameter msg3-Alpha, if configured, or equal to 1. • p is a parameter that depends on the subcarrier spacing (SCS) • wRB,t>™c(0 is the bandwidth of the PUSCH resource assignment expressed in number of resource blocks for PUSCH transmission occasion i on active UL BWP b of carrier f of serving cell c • PLbj.ciqd) is a downlink pathloss estimate in dB calculated by the UE using the same RS resource index qd as for a corresponding PRACH transmission, i.e., the SSB beam • Atf,VX0 = 10to£10 - 1) • for Ks = 1.25 and = 0 for Ks = 0 where Ks is provided by higher-layer parameter deltaMCS. BPRE and £0™. computed as o BPRE = Sr=o kv / nre, where C is a number of transmitted code blocks, Kr is a size for code block r, and NRE is a number of resource elements WPUSCH fn_1 determined as WRE = / Wp™?(0 • N™data(i,j), is a number of symbols for PUSCH transmission occasion i on active UL BWP b of carrier f of serving cell c, NBBdata(i, / ) is a number of subcarriers excluding DM-RS subcarriers and phase-tracking RS samples in PUSCH symbol j, 0 <j <CyS,r,X0 oPUSCH _ 1 ° Hoffset • fb,r,c(i’ I) is the PUSCH power control adjustment state. Msg5 (RRC setup complete message) refers to the PUSCH scheduled via DCI 0_0 with CRC scrambled via C-RNTI. As mentioned above, the above formula is also used to calculate the transmission power for Msg5. One difference between the calculations of transmission power for Msg3 and transmission power for Msg5 lies in the determination of the quantity referred to as the PUSCH power control adjustment state fbifiC(i,I). Since Msg5 is not the first PUSCH transmission by the UE, the power control adjustment state for Msg5 is calculated as a function of the power control adjustment state of the Msg3 transmission or re-transmission as = + wherein i0 = 1 in this case (i.e. previous PUSCH transmission - Msg3) and ^puscha / ,e(mj) in this case represents the TPC command included in the DCI scheduling the Msg5. In other words, the power control adjustment state used for the calculation of transmission power for Msg3 is inherited by the calculation of transmission power for Msg5. According to example embodiments, the above-mentioned scaling factor y is directly or indirectly incorporated into the power control adjustment state fb,f,c(i, 0 in the above formula. Scaling factor value dependent on number of transmission repetitions In one example, the scaling factor y has a value dependent on the number of transmission repetitions for the successful instance of sending Msg1 (i.e. the number of transmission repetitions for the sending of Msg1 that resulted in the reception at UE of a Msg 2 RAR carrying the preamble ID used by the UE for the Msg1 sending). According to one example, the definition of scaling factor y is hard-coded into the UE, and is an additive factor. According to one example, the scaling factor is defined as 10logw(N), where N is the number of transmission repetitions for the successful instance of sending Msg1. For this example of contention-based random access (CBRA), UE is configured one or more RSRP (reference signal received power) thresholds (each threshold associated to a number of transmission repetitions for a Msg1 sending) for determination of the number of transmission repetitions for a Msg1 sending. UE determines the number of transmission repetitions to perform for a Msg1 sending based on a comparison between the measured SSB-RSRP and the one or more RSRP thresholds. Such determined number of transmission repetitions might however change after a number of Msg1 sendings (first sending and re-sendings), with the UE determining a larger number of transmission repetitions. According to one example, N is the determined number of transmission repetitions for the successful instance of sending Msg1 (referred to also as the nominal number of repetitions), regardless of whether UE actually performed all the configured transmission repetitions. For example, it may be that UE has to drop one or more of the configured transmission repetitions because of a collision with other channels. According to an alternative example, N is the actual number of transmission repetitions performed by the UE for the successful instance of the sending of Msg1, regardless of whether or not the actual number of repetitions equals the nominal number of repetitions. According to one example, the scaling factor y has a value dependent on at least: (a) the number of transmission repetitions for the successful instance of sending Msg1; (b) the specific gNB’s implementation; and (c) on the considered deployment. This allows gNB to set the increase in power for the Msg3 depending on the combining gain expected from a number of transmission repetitions. Scaling factor value determined at higher layer According to one example, the scaling factor y value is configured at a protocol layer higher than the medium access control (MAC) layer at which transmission power is calculated (referred to here as a higher layer). According to one example, there are a plurality of possible values specified for the scaling factor y at a higher layer, and one of the plurality of possible values is indicated to the MAC layer of the UE. For example, there may be two possible values for the scaling factor y; and one of the two values is indicated to UE by using either the least significant bit (LSB) or the most significant bit (MSB) of the transmit power control (TPC) field of the Msg 2 UL grant (size 3 bits), wherein the mapping between configured values and codepoints is from lowest to highest, i.e., LSB / MSB set to 0 indicates uses of the lowest of the two values, and LSB / MSB set to 1 indicates the highest of the two values. Alternatively, one of two possible values for the scaling factor is indicated to UE by DCI FORMAT 0_0 with CRC scrambled with TC-RNTI by using either the LSB or the MSB of the TPC field of the DCI (size 2 bits), wherein the mapping between configured values and codepoints is from lowest to highest, i.e., LSB / MSB set to 0 indicates the lowest of the two values, and LSB / MSB set to 1 indicates the highest of the two values. Examples of using the Msg2 UL grant and DCI FORMAT 0_0 for indicating the scaling factor value are illustrated below. TPC Command carried by Msg2 UL grant (MSB indication of one or two possible values for scaling factor) TPC command 0 1 2 3 4 5 6 7 Codepoint 000 001 010 011 100 101 110 111 Smsg2,b,f,c [dB] 2 4 6 8 2 4 6 8 Scaling factor Yo Yo Ko Xo Xi Xi Yi Xi TPC Command carried by Msg2 UL grant (LSB indication of one of two possible values for the scaling factor) TPC command 0 1 2 3 4 5 6 7 Codepoint 000 001 010 011 100 101 110 111 6msg2,b,f,c [dB] 2 2 4 4 6 6 8 8 Scaling factor Yo Ki 7o Xi Yo 7i Yo 7i TPC Command carried by DCI format 0_0 (MSB indication of one of two possible values for the scaling factor) TPC command 0 1 2 3 Codepoint 00 01 10 11 8pUSCH,b,f,c(i’(Y) [dB] 1 4 1 4 Scaling factor 7o 7o 7i 7i TPC Command carried by DCI format 0_0 (LSB indication of one of two possible values for the scaling factor) TPC command 0 1 2 3 Codepoint 00 01 10 11 8puSCH,b,f,c^>0) [dB] 1 1 4 4 Scaling factor Yo 7i 7o 7i According to another example, 2L possible values for the scaling factor y are higher-layer configured, wherein L is the bit-width of the TPC field in the corresponding scheduling command. For example, one of the 2L possible values for the scaling factor may be indicated to UE in the dynamic signaling of 8mSg2iblflC via TPC command carried by Msg2 UL grant, i.e., 8mSg2,b,f,c = Smsg2,b,f,c + Y- An example for mapping between TPC value and corresponding power control values is shown in the tables below. The scaling factor may be seen as added directly to 8mSg2bfC. TPC Command carried by Msg2 UL grant, indicating one of 2L possible values for the scaling factor TPC command 0 1 2 3 4 5 6 7 Codepoint 000 001 010 011 100 101 110 111 Legacy 6msg2,b,f,c [dB] -6 -4 -2 0 2 4 6 8 ^msg2,b,f,c + Yi -6 + y0 -4 + / i -2 + y2 Y3 2 + y4 4 + / 5 6 + / 6 8 + y7 ^msg2,b,ffc + Y l^B] —6 + y -4 + y —2 + / Y 2 + y 4 + / 6 + / 8 + / Alternatively, one of the 2L possible values for the scaling factor is indicated to UE by dynamic signaling of 8PUSCH bifiC(i, 0) via DCI format 0_0 with CRC scrambled with TC-RNTI, i.e. 8pUSCH bifiC(i, 0) = 8PUSCH bifiC(i, 0) + y. An example for mapping between TPC value and corresponding power control values is shown in the tables below. The scaling factor may be seen as added directly to 8PUSCH 0). TPC Command carried by DCI format 0_0, indicating one of 2L possible values for the scaling factor TPC command 0 1 2 3 Codepoint 00 01 10 11 8puSCH .b.f MB] -4 -1 1 4 8puSCH,b,f,c + Y i [dB] -4 + / o -1 + / i 1+ / 2 3 + / 3 8puscH,b,f,c + Y [dB] -4 + / -1 + y 1 + / 3 + y Fixed value for scaling factor According to another example, the value of scaling factor y does not depend on the specific number of transmission repetitions for the successful instance of sending Msg1. Whenever a successful instance of sending Msg1 comprises transmission repetitions, the scaling factor has the same value regardless of the specific number of transmission repetitions. The fixed value for the scaling factor may be hardcoded into the UE, or may be configured at UE via higher layer signaling. Incorporating the scaling factor into the power control adjustment state The scaling factor y may be incorporated directly or indirectly into the power control adjustment state. According to one example of indirect incorporation, the scaling factor y is added to the parameter bPrampuprequestedt^c in the ^Prampup,b,f,c formula below specified by TS 38.213. max 0 P CMKXJ'C 101og10(2"y +P0^cu,tj.c + △tF.MV (0) +(^msg2,b,f.c ) , AP ‘-a rampuprequested,b,f,c Wherein the value kPrampup,b,f,c derived from the above formula is used to calculate the above-mentioned power adjustment state according to the formula below for the Msg3 transmission also specified by TS 38.213: fb,r,c^l) = AAampuP<v^ + smSg2,b,f,c, where I = 0 and - smsS2,b, / ,c is a TPC command value indicated in a random access response grant of the random access response message corresponding to a PRACH transmission according to Type-1 random access procedure, or in a random access response grant of the random access response message corresponding to a MsgA transmission according to Type-2 random access procedure with RAR message(s) for fallbackRAR, on active UL BWP b of carrier / of serving cell c, and - APrampup requested,b,f,c is provided by higher layers at the UE and corresponds to the total power ramp-up requested by higher layers from the first to the last random access preamble for carrier / in the serving cell c, M^sb™c(0) is the bandwidth of the PUSCH resource assignment expressed in number of resource blocks for the first PUSCH transmission on active UL BWP b of carrier / of serving cell c, and ATF b ^c(0) is the power adjustment of first PUSCH transmission on active UL BWP b of carrier f of serving cell c. According to one example of direct incorporation n, the scaling factor y is one of a plurality of quantities summed to calculate the power adjustment state fb f c(0,1). / v,c(0,0 = Prampup,b,f,c T ^msg2,b,f,c + Y ■ According to another example, the scaling factor y may also be added to the quantity 101og10(2^-M™c (0)) +P ' O_PUSCH,b, / , (0) + « / ,jjC(0) • PLC + &TF,b,f,c T ^msg2,b,f,c< used in the formula further above for calculating 8.Prampupbfc ■ This may be seen as an implementation according to which the scaling factor y is added to 8msg2b^c. Fig. 4 shows an example of operations at UE according to some example embodiments, for the example that the definition of scaling factor y is hardcoded into the UE as 10*logw(N), wherein N is the number of transmission repetitions for the successful instance of sending Msg1. UE determines to send Msg1 by a sending operation for which the configured number of transmission repetitions is four (STEP 400). UE sends the Msg1 (four transmission repetitions) (STEP 402). UE does not use PCmax for the sending of Msg1. In other words, UE does not send Msg1 at maximum transmission power, and there is scope to increase the transmission power for the Msg3 transmission later in the random access procedure. UE makes all of the configured number (four) of transmission repetitions. None of the configured number of transmission repetitions is dropped. Based on detection of Msg2 RAR from the gNB, UE determines that this instance of sending the Msg1 (4 transmission repetitions) was successful (STEP 404). UE has not already applied any power ramp-up for this random access procedure (i.e. has not applied any power ramp up to the transmission power for sending Msg1) and is not transmitting at maximum transmission power. Accordingly, &Prampuprequested,b,f,c = 0. UE determines whether the value calculated from the formula max (0,PCMAX - (10 log10 + Po_pusch,v,c(°) + ah, / ,c(°) ' P^c + &TF,b,f,c + 8ms32,b,f,c)) is greater or not than &PrampuPrequested,b,f,c + 10 log10 N (= 10logio(N) since &PrampuPrequested,b,f,c = In this example, it is assumed that the value calculated from the formula is greater than 10logio(N), i.e. that UE determines that the power head room calculated by UE given higher layer configuration and after receiving the scheduling parameters for Msg3 transmission is larger than the scaling factor; and UE determines APrampup,b,f,c ^PrampuPr equested,b,f,c + lOlog-^p / V 101ogig4 (STEP 306). UE sends Msg3 with a transmission power adjusted by ^Prampup,b,f,c = 10 log10 4 (STEP 408). Based on detection of Msg4 from gNB, UE determines that the sending of Msg3 was successful (STEP 410). After receiving the Msg4 (and after sending the PLICCH HARQ-ACK and receiving PDCCH scheduling Msg5), UE sends Msg5 with a transmission power calculated based on a power control adjustment stateJ) = + wherein / ^(0,0 = Mrampup,b,f,c + = 101og10 4 + 8msg2tbiftC is the power control adjustment state used for transmission of the Msg3 (STEP 412). Similarly, the scaling factor may also be indirectly incorporated into the transmission power determination for further PUSCH messages after Msg5. Fig. 5 illustrates an example of operations at gNB according to some example embodiments. gNB determines one of a plurality of possible values for the scaling factor y, for use by UE for calculating the power control adjustment state in the event that a successful instance of sending Msg1 by UE comprised transmission repetitions (STEP 500). gNB sends an indication of the determined scaling factor value according to one of the techniques mentioned above (STEP 502). In the above example embodiments, applying the scaling factor to the power control adjustment state results in the scaling factor being automatically applied to both the calculation of transmission power for Msg3 (re)transmission and to the calculation of transmission power for the Msg5 transmission. The gain added due to the application of PRACH repetitions is inherited from Msg3 to subsequent PUSCH transmissions. Fig. 6 illustrates another example of operations at UE according to some example embodiments. UE determines to send Msg1 by a sending operation for which the configured number of transmission repetitions is two (STEP 500), and calculates transmission power = P1 for this instance of sending Msg1 (STEP 602). UE sends Msg1 (two transmission repetitions at power P1) (STEP 604). Based on a failure to detect Msg2 (RAR), UE determines that this first instance of sending Msg1 was unsuccessful (STEP 606). UE determines to make a second sending of Msg1 with the same number of transmission repetitions (i.e. two), but with a first power ramp of 2 dB applied to the previously calculated transmission power (STEP 608). UE makes the second sending of Msg1 with two transmission repetitions at transmission power = P1+2dB (STEP 610). Based on a failure to detect Msg2 (RAR), UE determines that this second instance of sending Msg1 was also unsuccessful (STEP 612). UE determines to make a third sending of Msg1 with the same number of transmission repetitions (i.e. two), but with an additional, second power ramp of 2 dB applied to the previously calculated transmission power (STEP 614). UE makes the third sending of Msg1 with two transmission repetitions at transmission power = P1+2dB+2dB (STEP 616). Based on a failure to detect Msg2 (RAR), UE determines that this third instance of sending Msg1 was also unsuccessful (STEP 618). UE determines to make a fourth sending of Msg1 with an increased number of transmission repetitions (e,g. four) (STEP 620), and re-calculates a transmission power = P1 for this fourth sending of Msg1 (STEP 622). In this example, this fallback to a higher number of transmission repetitions within a same MAC layer procedure occurs after three unsuccessful instances of sending Msg1, but UE may be configured to make the fallback after a different number of unsuccessful instances of sending Msg1 or to make the fallback based on other conditions, such as having reached a certain transmission power. UE makes the fourth sending of Msg1 with four transmission repetitions at transmission power = P1 (STEP 624). Based on a failure to detect Msg2 (RAR), UE determines that this fourth instance of sending Msg1 was also unsuccessful (STEP 626). UE determines to make a fifth sending of Msg1 with the same number of transmission repetitions (i.e. four), but with a first power ramp of 2 dB applied to the transmission power (STEP 628). UE makes the fifth sending of Msg1 with four transmission repetitions at transmission power = P1+2dB (STEP 630). Based on detection of Msg2 (RAR) from the gNB, UE determines that this fifth instance of sending Msg1 was successful (STEP 632). UE determines to send Msg3, and determines &Prampupr equested,b, / ,c based on the amount of power ramp-up (i.e. 2dB) for the successful instance of sending Msg1 (i.e. the sending of Msg1 with four transmission repetitions) (STEP 634). UE calculates the transmission power for sending Msg3 based on ^Prampuprequested,b, / ,c and sends Msg3 with the calculated transmission power (STEP 636). Determining APrampuprequestedA / ;c for sending Msg3 based on the number of power ramps for only the successful instance of sending Msg1 (and not on the basis of a higher number of power ramps including also unsuccessful instances of Msg1 comprising fewer transmission repetitions) can avoid overestimating the transmission power for sending Msg3. Excessively high transmit power of Msg3 is avoided. It is noted that whilst some embodiments have been described in relation to 5G networks, similar principles can be applied in relation to other networks and communication systems. Therefore, although certain embodiments were described above by way of example with reference to certain example architectures for wireless networks, technologies and standards, embodiments may be applied to any other suitable forms of communication systems than those illustrated and described herein. It is also noted herein that while the above describes example embodiments, there are several variations and modifications which may be made to the disclosed solution without departing from the scope of the present invention. As used herein, “at least one of the following: ” and “at least one of ” and similar wording, where the list of two or more elements are joined by “and” or “or”, mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements. In general, the various embodiments may be implemented in hardware or special purpose circuitry, software, logic or any combination thereof. Some aspects of the disclosure may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the disclosure is not limited thereto. While various aspects of the disclosure may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof. As used herein, the term “circuitry” may refer to one or more or all of the following: (a) hardware-only circuit implementations (such as implementations in only analog and / or digital circuitry) and (b) combinations of hardware circuits and software, such as (as applicable): (i) a combination of analog and / or digital hardware circuit(s) with software / firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and (iii) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.” This definition of circuitry applies to all uses of this term herein, including in any claims. As a further example, as used herein, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device. The embodiments of this disclosure may be implemented by computer software executable by a data processor of the mobile device, such as in the processor entity, or by hardware, or by a combination of software and hardware. Computer software or program, also called program product, including software routines, applets and / or macros, may be stored in any apparatus-readable data storage medium and they comprise program instructions to perform particular tasks. A computer program product may comprise one or more computerexecutable components which, when the program is run, are configured to carry out embodiments. The one or more computer-executable components may be at least one software code or portions of it. Further in this regard it should be noted that any blocks of the logic flow as in the Figures may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions. The software may be stored on such physical media as memory chips, or memory blocks implemented within the processor, magnetic media such as hard disk or floppy disks, and optical media such as for example DVD and the data variants thereof, CD. The physical media is a non-transitory media. The term “non-transitory,” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM). The memory may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The data processors may be of any type suitable to the local technical environment, and may comprise one or more of general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASIC), FPGA, gate level circuits and processors based on multi core processor architecture, as non-limiting examples. Various example embodiments of the disclosure may be practiced in various components such as integrated circuit modules. The design of integrated circuits is by and large a highly automated process. Complex and powerful software tools are available for converting a logic level design into a semiconductor circuit design ready to be etched and formed on a semiconductor substrate. The scope of protection sought for various example embodiments of the disclosure is set out by the independent claims. The example embodiments and features thereof, if any, described in this disclosure that do not fall under the scope of the independent claims are to be interpreted as examples useful for understanding various example embodiments of the disclosure. The foregoing description has provided, byway of non-limiting and illustrative examples, a full and informative description of the various example embodiments of this disclosure. However, various modifications and adaptations may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings and the claims. However, all such and similar modifications of the teachings will still fall within the various example embodiments of the disclosure as set forth in the claims. By way of non-limiting and illustrative example, there is a further example embodiment comprising a combination of one or more example embodiments with any of the other example embodiments previously discussed.

Claims

1. User equipment, comprising means for:in the event of a receiving a response to an instance of sending a first message of a random access procedure, determining a transmission power for sending a second message of the random access procedure, wherein the determining of the transmission power for sending the second message is partly based on a quantity having a value dependent on whether or not the instance of sending the first message comprises transmission repetitions; andafter receiving a response to the sending of the second message, determining a transmission power for sending a third message also based at least partly on the quantity.

2. The user equipment according to claim 1, wherein the quantity is based at least partly on a factor having a value dependent on a number of transmission repetitions for the instance of sending the first message.

3. The user equipment according to claim 2, wherein the number of transmission repetitions is the actual number of transmission repetitions made by the user equipment for the instance of the sending of the first message.

4. The user equipment according to claim 2, wherein the number of transmission repetitions is a configured number of transmission repetitions determined by the user equipment for the instance of the sending of the first message, irrespective of whether one or more of the transmission repetitions are not made the user equipment.

5. The user equipment according to claim 1, wherein the quantity is based at least partly on a factor having a value configured at a layer above the medium access control layer.

6. The user equipment according to claim 1, wherein the quantity is based at least partly on a factor having a value based on an indication from the radio access network.

7. The user equipment according to claim 6, wherein the indication is provided by a random access response message of the random access procedure.

8. The user equipment according to claim 6, wherein the indication is provided by downlink control information from the radio access network.

9. The user equipment according to claim 1, wherein the quantity is based at least partly on a factor having a value independent of a number of transmission repetitions for the instance of sending the first message.

10. The user equipment according to claim 1, wherein the quantity is incorporated into a formula for calculating the transmission power for sending the second message and for calculating the transmission power for sending the third message.

11. The user equipment according to claim 1, wherein the quantity is a function of at least a power ramping parameter, and the power ramping parameter is a function of at least a factorhaving a value dependent on a number of transmission repetitions for the instance of sending the first message.

12. The user equipment according to claim 1, wherein the quantity comprises a sum of at least a power ramping parameter and a factor having a value dependent on a number of transmission repetitions for the instance of sending the first message.

13. The user equipment according to any preceding claim, wherein the quantity comprises a power control adjustment state for a formula determining transmission power.

14. A radio access network node, comprising means for:sending to a user equipment an indication of a value of a factor for use by the user equipment as at least part basis for determining a quantity for determining transmission power for sending further messages of a random access procedure in the event of the user equipment receiving a response to an instance of sending a first message of the random access procedure, wherein the use by the user equipment of the value of the factor is dependent on whether or not the instance of sending the first message comprises transmission repetitions.

15. The radio access network node according to claim 14, wherein the quantity comprises a power control adjustment state for a formula determining transmission power for the further messages of the random access procedure.28

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