WO2021056462A1

WO2021056462A1 - Termination of monitoring window in random access procedure

Info

Publication number: WO2021056462A1
Application number: PCT/CN2019/108704
Authority: WO
Inventors: Samuli Turtinen; Chunli Wu; Sami Hakola; Emad Farag
Original assignee: Nokia Shanghai Bell Co., Ltd.; Nokia Solutions And Networks Oy; Nokia Technologies Oy
Priority date: 2019-09-27
Filing date: 2019-09-27
Publication date: 2021-04-01
Also published as: WO2021056462A8; CN114503771A; CN114503771B

Abstract

Embodiments of the present disclosure relate to termination of monitoring window in random access procedure. A first device transmits to a second device a first random access request comprising a first random access preamble and data. The first device receives an identification of the first random access preamble from the second device. Responsive to receiving the identification without a grant for retransmitting the data, the first device cease monitoring a response to the first random access request.

Description

TERMINATION OF MONITORING WINDOW IN RANDOM ACCESS PROCEDURE

FIELD

Embodiments of the present disclosure generally relate to the field of telecommunication and in particular, to devices, methods, apparatuses and computer readable storage media for termination of monitoring window in random access procedure.

BACKGROUND

Various wireless cellular communication systems have been implemented and are being implemented. Mobile communication systems have been developed and are being developed to meet the increasing demand for communication services. With the rapid advance of technologies, the mobile communication systems have evolved to the level capable of providing high speed data communication service beyond the early voice-oriented services.

A random access (RA) procedure refers to a procedure for a terminal device to establish or reestablish a connection with a network device such as an Evolved NodeB (eNB) or a 5G gNodeB (gNB) . A contention based random access procedure can facilitate the possibility that multiple communication devices may be interested in attempting to access the network device through the RA procedure at the same or similar point in time. Once access has been established and/or confirmed, the network device can assign resources to a particular terminal device in support of the uplink communication with the network device.

SUMMARY

In general, example embodiments of the present disclosure provide a solution for termination of monitoring window in random access procedure.

In a first aspect, there is provided a first device. The first device comprises at least one processor; and at least one memory including computer program codes; the at least one memory and the computer program codes are configured to, with the at least one processor, cause the first device to transmit, to a second device, a first random access request comprising a first random access preamble and data; receive an identification of the first random access preamble from the second device; and responsive to receiving the identification without a grant for retransmitting the data, cease monitoring a response to the first random access request.

In a second aspect, there is provided a second device. The second device comprises at least one processor; and at least one memory including computer program codes; the at least one memory and the computer program codes are configured to, with the at least one processor, cause the second device to receive, from a first device, a first random access request comprising a first random access preamble and data; and responsive to receiving the first random access preamble and a failure in decoding the data, determine an identification of the first random access preamble; and transmit, to the first device, the identification without a grant for retransmitting the data.

In a third aspect, there is provided a method. The method comprises: transmitting, at a first device to a second device, a first random access request comprising a first random access preamble and data; receiving an identification of the first random access preamble from the second device; and responsive to receiving the identification without a grant for retransmitting the data, ceasing monitoring a response to the first random access request.

In a fourth aspect, there is provided a method. The method comprises: receiving, from a first device at a second device, a first random access request comprising a first random access preamble and data; and responsive to receiving the first random access preamble and a failure in decoding the data, determining an identification of the first random access preamble; and transmitting, to the first device, the identification without a grant for retransmitting the data.

In a fifth aspect, there is provided an apparatus. The apparatus comprises: means for means for transmitting, at a first device to a second device, a first random access request comprising a first random access preamble and data; means for receiving an identification of the first random access preamble from the second device; and means for responsive to receiving the identification without a grant for retransmitting the data, ceasing monitoring a response to the first random access request.

In a sixth aspect, there is provided an apparatus. The apparatus comprises: means for means for receiving, from a first device at a second device, a first random access request comprising a first random access preamble and data; means for responsive to receiving the first random access preamble and a failure in decoding the data, determining an identification of the first random access preamble; and means for transmitting, to the first device, the identification without a grant for retransmitting the data.

In a seventh aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method according to the third aspect.

In an eighth aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method according to the fourth aspect.

It is to be understood that the summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Some example embodiments will now be described with reference to the accompanying drawings, where:

Fig. 1 illustrates an example communication system in which embodiments of the present disclosure may be implemented;

Fig. 2A illustrate an example flowchart illustrating a 2-step contention-based random access procedure;

Fig. 2B illustrate an example flowchart illustrating fallback from 2-step contention-based random access to 4-step contention-based random access;

Fig. 3 illustrates a flowchart illustrating a process for termination of monitoring window in random access procedure according to some example embodiments of the present disclosure;

Fig. 4 illustrates a flowchart illustrating a process for RA reattempt according to some example embodiments of the present disclosure;

Fig. 5 illustrates a flowchart of a method according to some example embodiments of the present disclosure;

Fig. 6 illustrates a flowchart of a method according to some example embodiments of the present disclosure;

Fig. 7 illustrates a simplified block diagram of a device that is suitable for implementing embodiments of the present disclosure; and

Fig. 8 illustrates a block diagram of an example computer readable medium in accordance with some embodiments of the present disclosure.

Throughout the drawings, the same or similar reference numerals represent the same or similar element.

DETAILED DESCRIPTION

Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones described below.

In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

References in the present disclosure to “one embodiment, ” “an embodiment, ” “an example embodiment, ” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It shall be understood that although the terms “first” and “second” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the listed terms.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a” , “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” , “comprising” , “has” , “having” , “includes” and/or “including” , when used herein, specify the presence of stated features, elements, and/or components etc., but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof.

As used in this application, 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

(c) 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 in this application, including in any claims. As a further example, as used in this application, 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.

As used herein, the term “communication network” refers to a network following any suitable communication standards, such as Long Term Evolution (LTE) , LTE-Advanced (LTE-A) , Wideband Code Division Multiple Access (WCDMA) , High-Speed Packet Access (HSPA) , Narrow Band Internet of Things (NB-IoT) , 5G New Radio (NR) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the future fifth generation (5G) communication protocols, and/or any other protocols either currently known or to be developed in the future. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

As used herein, the term “network device” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP) , for example, a node B (NodeB or NB) , an evolved NodeB (eNodeB or eNB) , a NR NB (also referred to as a gNB) , a Remote Radio Unit (RRU) , a radio header (RH) , a remote radio head (RRH) , a relay, a low power node such as a femto, a pico, an Integrated Access Backhaul (IAB) node, and so forth, depending on the applied terminology and technology.

The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE) , a Subscriber Station (SS) , a Portable Subscriber Station, a Mobile Station (MS) , or an Access Terminal (AT) . The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA) , portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE) , laptop-mounted equipment (LME) , USB dongles, smart devices, wireless customer-premises equipment (CPE) , an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD) , a vehicle, a drone, a medical device and applications (e.g., remote surgery) , an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts) , a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. In the following description, the terms “terminal device” , “communication device” , “terminal” , “user equipment” and “UE” may be used interchangeably.

Fig. 1 illustrates an example communication system 100 in which example embodiments of the present disclosure may be implemented. The communication system 100 includes a plurality of first devices 110-1, 110-2 …and 110-N (where N is an integer number) , which can be collectively referred to as “first devices” 110 or individually referred to as a “first device” 110. The communication system 100 also includes a second device 120. The first devices 110 and the second device 120 may communicate with each other. In this example, the first devices 110 are illustrated as terminal devices, and the second device 120 is illustrated as a network device serving the terminal devices.

Thus, the serving area of the second device 120 is called as a cell 102. It is to be understood that the number of devices (both the first devices and the second device) and/or cells is only for the purpose of illustration without suggesting any limitations. The system 100 may include any suitable number of devices and cells adapted for implementing embodiments of the present disclosure.

Communications in the communication system 100 may be implemented according to any proper communication protocol (s) , comprising, but not limited to, cellular communication protocols of the first generation (1G) , the second generation (2G) , the third generation (3G) , the fourth generation (4G) and the fifth generation (5G) and on the like, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and/or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: Code Division Multiple Access (CDMA) , Frequency Division Multiple Access (FDMA) , Time Division Multiple Access (TDMA) , Frequency Division Duplex (FDD) , Time Division Duplex (TDD) , Multiple-Input Multiple-Output (MIMO) , Orthogonal Frequency Division Multiple (OFDM) , Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM) , Discrete Fourier Transform spread OFDM (DFT-s-OFDM) and/or any other technologies currently known or to be developed in the future.

In the communication system 100, upon a connection is established, the first devices 110 and the second device 120 can communicate data and control information to each other. In the case where the first device 110 is the terminal device and the second device 120 is the network device, a link from the second device 120 to the first device 110 is referred to as a downlink (DL) , while a link from the first device 110 to the second device 120 is referred to as an uplink (UL) .

Typically, in order to communicate with each other, for example, the first device 110 may initiate a RA procedure to establish or re-establish a connection with the second device 120. The RA procedure may be triggered by a number of events, for example but not limited to, initial access, Radio Resource Control (RRC) connection re-establishment, beam failure recovery, UL data arrival, Scheduling Request (SR) failure, etc.

Currently, three types of RA procedures are supported, including a 4-step contention-based random access (CBRA) procedure, a 2-step CBRA procedure and a contention-free random access (CFRA) procedure. The RA procedures, such as the 4-step CBRA and the 2-step CBRA, may be based on contention among multiple terminal devices. The terminal device selects the type of random access procedure based on the network configuration. For example, a Reference Signal Receiving Power (RSRP) threshold may be configured for the terminal device to select between the 2-step CBRA and the 4-step CBRA.

In a 4-step CBRA procedure (not shown) , a terminal device selects and transmits a random access preamble RAP (which may be referred to as “MSG1” ) to a network device. The network device then transmits a random access response RAR (which may be referred to as “MSG2” ) to the random access preamble. Upon receipt of the random access response, the terminal device transmits scheduled transmission (which may be referred to as “MSG3” ) to the network device. The network device transmits, depending on contention across its serving terminal devices, a contention resolution (which may be referred to as “MSG4” ) to the terminal device.

It has been agreed to employ a 2-step CBRA procedure in order to achieve quick random access. An example of the 2-step CBRA procedure is briefly introduced below with reference to Fig. 2A. In a RA procedure 200 of Fig. 2A, a terminal device transmits 210 a first message (which may be referred to as “MSGA” ) to a network device. The first message combines a random access preamble (similar as “MSG1” ) and uplink data (similar as “MSG3” ) . For example, MSGA includes a random access preamble on physical random access channel (PRACH) and a payload on physical uplink shared channel (PUSCH) . After MSGA transmission, the terminal device starts to monitor for a response from the network device within a configured window.

Depending on contention across its serving terminal devices, the network device may transmit 220 a second message (which may be referred to as “MSGB” ) to the terminal device. The second message may combine a random access response (similar as “MSG2” ) and a contention resolution (similar as “MSG4” ) . If contention resolution is received successfully in the MSGB, the terminal device sends a Hybrid Automatic Repeat reQuest (HARQ) feedback to the network device and ends the random access procedure as shown in Fig. 2A.

In general, MSGB may include zero or one backoff indication; zero or more fallback indications to schedule MSG3 transmission; zero or more contention resolution messages; and signalling radio bearers (SRB) data for zero or one terminal device along with the contention resolution message. In some cases, contention resolution may not be included in the MSGB, for example in the case of fallback from 2-step CBRA to MSG3 transmission (4-step CBRA) .

An example procedure of fallback from 2-step CBRA to 4-step CBRA is shown in Fig. 2B. In the example procedure 202 of Fig. 2B, a terminal device transmits 230 to a network device MSGA, which includes a random access preamble on PRACH and a payload on PUSCH. The network device may detect only the preamble part of the MSGA and transmits 240 to the terminal device MGSB, which in this example includes a fallback indication. Then, the terminal device falls back to the 4-step CBRA and transmits 250 MSG3 to the network device. The network device transmits 260 MSG4 to the terminal device. The terminal device can be further configured to switch to 4-step CBRA after a number of attempts with 2-step CBRA.

As can be seen from above, the network device can transmit a fallback indication to the terminal device in the case where it is unable to decode the PUSCH part of the MSGA. With this approach, the network device indicates in MSGB the RAR similarly to 4-step procedure and gives the terminal device a Temporary Cell Radio Network Temporary Identity (TC-RNTI) , UL grant for MSG3 transmission, and a Timing Advance Command (TAC) . Moreover, the transport block (TB) size offered by the UL grant in the fallback RAR shall be the same as the TB size offered for payload transmission in MSGA; otherwise, the behavior of the terminal device is not defined.

There are several scenarios where conventional RA procedure may be questionable, especially for the termination of monitoring window for MSGB. For example, when two or more terminal devices transmit in the same MSGA resources (which may be referred to as scenario 1) , i.e., using the same random access preamble ID (RAPID) as well as the same PUSCH resource, it is possible that the network device cannot decode the PUSCH content especially if the power level received from the terminal devices is comparable at the receiver of the network device. However, it could be possible for the network device to recognize the PUSCH collision based on the same preamble received more than one time (two or more peaks, separated by a delay greater than the delay spread, within the same search window of a certain cyclic shift) or in general based on detection of PUSCH discontinuous transmission (DTX) .

Furthermore, another scenario (which may be referred to as scenario 2) may be as below. If the TB size information related to the PUSCH part of the MSGA is indicated in Uplink Control Information (UCI) (i.e., UCI would be multiplexed along with the PUSCH) , the network device may receive only the random access preamble but cannot know the PUSCH size if the UCI cannot be successfully decoded. As has been agreed and mentioned above, the TB size of the fallback RAR shall be the same as the TB size offered for payload transmission in MSGA, otherwise the behavior of the terminal device is not defined which assumes this shall be handled by the network device. In the case where the network device cannot determine the PUSCH size used by the terminal device, providing a TB size for the terminal device in the fallback RAR becomes impossible (unless only single size would be used in the cell) .

In both of the above scenarios, providing the fallback RAR with UL grant becomes questionable. In scenario 1, the MSG3 transmissions will fail similarly to the PUSCH part of MSGA as both the terminal devices will transmit on the same UL grants offered. In scenario 2, it is not possible for the network device to determine the TB size to offer for the terminal device in the fallback RAR.

In conventional solutions, for both of the above scenarios, the network device could just ignore the terminal device (s) and could not respond to the RA request from the terminal device (s) . However, the terminal device (s) may be still monitoring MSGB from the network device. Given that monitoring window for MSGB could be rather long (for example, up to 64ms if comparing to Contention Resolution Timer) , such behavior will lead to long RA procedure lengths for the terminal device (s) as the terminal device (s) need to wait for the monitoring window to expire before re-attempt. This in turns is not beneficial as using the 2-step CBRA is intended to reduce RA procedure latency.

According to some example embodiments of the present disclosure, there is proposed a solution for termination of monitoring window in RA procedure. The solution is related to the RA procedure where a random access preamble and data on shared channel are transmitted together in a RA message, such as MSGA. One example of such RA procedure is a 2-step CBRA procedure. It would be appreciated that any other suitable RA procedures may also be applicable, for instance, a 2-step CFRA procedure. According to the solution, a first device transmits a random access request to a second device, and the random access request comprises a random access preamble on random access channel and data on for example shared channel. The first device receives, from the second device, an identification of the transmitted random access preamble without a grant for retransmitting the data. Upon receiving the identification of the random access preamble, the first device ceases monitoring a response to the random access request. In this way, the monitoring window for a response to the random access request can be early terminated and latency of random access can thus be reduced.

Some example embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Reference is now made to Fig. 3, which shows a process 300 for termination of monitoring window in RA procedure according to an example embodiment of the present disclosure. For the purpose of discussion, the process 300 will be described with reference to Fig. 1. The process 300 may involve the first device 110 and the second device 120 as illustrated in Fig. 1.

In the process 300, the first device 110 transmits 305 a random access request (which is also referred to as first random access request) to the second device 120. The first random access request comprises a RAP (which is also referred to as a first RAP) and data. This random access procedure may be the 2-step CBRA procedure described above and the random access request may be the first message, i.e. MSGA. For example, in the case where the first device 110 is a terminal device and the second device 120 is a network device, the first random access request may comprise a preamble on PRACH and uplink payload on PUSCH.

Once the first random access request is transmitted 305, the first device 110 may start to monitor a response to the first random access request within a monitoring window. For example, the first device 110 may monitor the MSGB as mentioned above within the motoring window. Only for purpose of discussion and without any limitation, the MSGB as mentioned above, which may include zero or one backoff indication, zero or more fallback indications, zero or more contention resolution messages, and SRB data along with the contention resolution message, is referred to as conventional MSGB herein.

If the second device 120 receives the first RAP but fails to decode the data (e.g. payload on the PUSCH) transmitted by the first device 110, the second device 120 determines 310 an identification of the first RAP, for example, the RAPID. For example, similar as the scenario 1 as mentioned above, if more than one first devices 110 (e.g., the first devices 120-1 and 120-N as shown in Fig. 1) use the same RAPID in the 2-step CBRA procedure, the second device 120 may fail to decode the PUSCH parts of MSGAs from these first devices 110. In such a case, providing fallback RAR with resource grant to these first devices 110 would result in further collisions.

As another example similar as the scenario 2 as mentioned above, the second device 120 may fail to decode the PUSCH part of MSGA from the first device 110 and also fails to determine the TB size for data transmission in MSGA, for example due to failure in decoding UCI. In such a case, since the second device 120 does not know about the TB size for data transmission, resource grant (e.g. UL grant) cannot be provided to the first device 110.

As a result, the second device 120 transmits 315 to the first device 110 the identification of the first RAP, for example, the RAPID. The identification of the first RAP is transmitted without a grant for retransmitting the data. In some example embodiments, the second device 120 may further transmit a backoff indication to the first device 110. For example, the backoff indication may be transmitted along with the identification of the first RAP. Only for purpose of discussion and without any limitation, the message transmitted 315 from the second device 120 to the first device 110 is referred to as a proposed MGSB. As such, the proposed MSGB may comprise the identification of the first RAP and optionally the backoff indication. It is to be understood that the proposed MSGB may comprise a further portion not mentioned herein.

After receiving the identification of the first RAP without a grant for retransmitting the data, the first device 110 ceases 320 monitoring the response to the first random access request. For example, after receiving the proposed MSGB with RAPID without a grant for retransmitting the data, the first device 110 ceases monitoring the conventional MSGB. As a result, the monitoring window for the MSGB is terminated at the first device 110. In this way, the first device 110 is aware of that the first RAP in the MSGA has been received by the second device 120 but the payload is unsuccessfully decoded and no further response would be received from the second device 120.

After the termination of the monitoring window, the first device 110 may reattempt to access the second device 120. The first device 110 may reattempt to access the second device 120 immediately after the reception of RAPID or immediately after the termination of the monitoring window. Alternatively, the first device 110 may reattempt to access the second device 120 based on a backoff indication for example received from the second device 120. The reattempt to access the second device 120 may be based on the same RA procedure (e.g., 2-step CBRA) as the previous attempt or based on a different RA procedure (e.g., 4-step CBRA) from the previous attempt. Some of such example embodiments will be described below with reference to Figs. 3 and 4.

In the proposed solution, the second device (e.g., the network device) is allowed to enable the first devices (e.g., the terminal devices) that collided with each other in MSGA transmission to stop monitoring MSGB and to directly reattempt MSGA or MSG1. For the first device of which the second device cannot decode the TB size used in PUSCH transmission of MSGA, the second device is also allowed to fallback such a first device to reattempt MSGA or MSG1. Therefore, the latency of a RA procedure such as the 2-step CBRA can be reduced compared to the conventional solution.

Still referring to Fig. 3, in some example embodiments, the first device 110 may perform the same RA procedure (e.g. 2-step CBRA) as the previous attempt to reattempt to access the second device 120. For example, the first device 110 may transmit 330 to the second device 120 a second random access request comprising a second RAP and the data. The second random access request may be MSGA of the 2-step CBRA. For example, in the case where the first device 110 is a terminal device and the second device 120 is a network device, the second random access request may comprise a preamble on PRACH and the payload on PUSCH. The second RAP may be the same as or different from the first RAP. The first device 110 may receive 335 from the second device 120 a MSGB including for example the contention resolution.

In the example embodiments where the backoff indication (e.g. a backoff indicator, BI) is received from second device 120 (e.g. in MSGB) , the first device 110 may perform 325 a backoff procedure based on the backoff indication to delay transmission of the second random access request. For example, the first device 110 may perform 325 the backoff procedure immediately after decoding the RAPID and terminating the monitoring window for conventional MSGB after which it will reattempt with MSGA transmission.

In some example embodiments, the first device 110 may perform no power ramping for both preamble transmission and data transmission. For example, if the first random access request is transmitted 305 with a first power for the first RAP and a second power for the data, then the first device 110 may transmit the second RAP with the first power and transmit the data with the second power when transmitting 330 the second random access request. For example, in the case where the first device 110 is a terminal device and the second device 120 is a network device, no power ramping is performed for both the RAP and the PUSCH part of MSGA.

In some example embodiments, the first device 110 may perform no power ramping for preamble transmission and perform power ramping for data transmission. For example, if the first random access request is transmitted with a first power for the first RAP and a second power for the data, then the first device 110 may transmit the second RAP with the first power and transmit the data with a third power greater than the second power when transmitting 330 the second random access request. For example, in the case where the first device 110 is a terminal device and the second device 120 is a network device, power ramping is only performed for the PUSCH part of MSGA.

In some example embodiments, the first device 110 may determine whether perform power ramping for preamble transmission and/or data transmission based on an indication from the second device 120. In other words, the second device 120 may indicate the first device 110 whether to perform power ramping for preamble transmission and/or data transmission. The second device 120 may configure a power ramping indication to indicate the first device 110 for which part (s) of the random access request to perform power ramping, for example, the preamble part, the data part or both. As an example, in the case of 2-step CBRA, the power ramping indication may indicate whether power ramping is to be performed on the preamble, the PUSCH part or both of the preamble and the PUSCH part.

In some example embodiments, the first device 110 may receive from the second device 120 the power ramping indication indicating whether power ramping is to be performed for data transmission and transmit 330 the second random access request based on the power ramping indication. In the case where the first device 110 is a terminal device and the second device 120 is a network device, the second device 120 may indicate the first device 110 whether it shall perform power ramping for the PUSCH part of MSGA.

In some example embodiments, the first device 110 may be configured with at least two sets of RAPs, for example by the second device 120. One set of the at least two sets of RAPs (which may be referred to as the first set of RAPs) may correspond to a plurality of TB sizes for data transmission. When an RAP in the first set of RAPs is used by the first device 110, a further indication may be used by the first device 110 to indicate the specific TB size used. For example, in the case where the first device 110 is a terminal device and the second device 120 is a network device, the first device 110 may use UCI to indicate the specific TB size used in MSGA.

The other set (s) of the at least two sets of RAPs may each correspond to a single TB size. As an example, a second set of RAPs may correspond to a particular TB size. As such, if a preamble in the second set of RAPs is used by the first device 110, the second device 120 may determine the TB size for data transmission of MSGA after receiving the preamble and no additional information is needed. Optionally, a third set of RAPs may correspond to another TB size that is different from the TB size which the second set of RAPs correspond to.

In such example embodiments, to transmit 330 the second random access request, the first device 110 may select the second RAP from the at least two sets of RAPs, based on the TB size used to transmit the data comprised in the first random access request. For example, when the first device 110 reattempts MSGA transmission in response to receiving proposed MSGB with the RAPID only (optionally with the backoff indication) , the first device 110 may select the RAP corresponding to a payload size that matches the payload of MSGA previously transmitted.

With reference to Fig. 3, some example embodiments where the reattempt to access the second device 120 is based on the same type of RA procedure as the previous attempt is described above. It is to be understood that aspects described above with respect to different example embodiments can be combined.

As mentioned above, the reattempt to access the second device 120 (which may be referred to as RA reattempt for purpose of discussion) may be based on a different RA procedure from the previous attempt. For example, in the case where the previous attempt is based on the 2-step CBRA, the RA reattempt may be based on the 4-step CBRA. In some example embodiments, the second device 120 may indicate the first device 110 of the random access mode for the RA reattempt.

Reference now is made to Fig. 4, which illustrates a flowchart illustrating a process 400 for RA reattempt according to some example embodiments of the present disclosure. The second device 120 may transmit 405 a mode indication to the second device. The mode indication may indicate at least a first random access mode and a different second random access mode. The previous attempt may be based on the first random access mode.

For example, the mode indication may indicate the type of RA procedure to be performed by the first device 110 for the RA reattempt. As an example, the first random access request may be based on the 2-step CBRA and the mode indication may indicate whether the 2-step CBRA or 4-step CBRA shall be performed by the first device 110 for the RA reattempt. It is to be understood that the mode indication may indicate any suitable type of RA procedures that can be employed by the first device 110 to access the second device 120. For example, the mode indication may indicate that one of the 2-step CBRA, the 4-step CBRA, or the CFRA shall be performed for the RA reattempt.

In some example embodiments, the mode indication may be semi-statically set. For example, the mode indication may be transmitted to the first device 110 in system information broadcast (SIB) or via a dedicated configuration for the first device 110. For example, in the case where the first device 110 is a terminal device and the second device 120 is a network device, the mode indication may be transmitted via a RRC signalling. In some example embodiments, the mode indication may be transmitted along with the identification of the first RAP, i.e. along with the proposed MSGB.

The first device 110 may determine 410 the random access mode to be used for the RA reattempt and transmit 415 to the second device 120 a random access request based on the determined random access mode. For example, if the mode indication indicates the 2-step CBRA, the random access request transmitted 415 to the second device 120 may be MSGA of the 2-step CBRA. If the mode indication indicates the 4-step CBRA, the random access request transmitted 415 to the second device 120 may be MSG1 of the 4-step CBRA.

In such example embodiments, load balancing can be achieved at the second device 120. If the second device 120 is undergoing high processing load on 2-step random access channel (RACH) , it may order certain first device (s) to continue with MSGA transmission or move some of the first devices to the 4-step CBRA.

It is to be understood that aspects described above with respect to Figs. 3 and 4 can be combined. As an example, aspects regarding power ramping and/or backoff indication may be incorporated into the process 400.

More details of the example embodiments in accordance with the present disclosure will be described with reference to Figs. 5-6.

Fig. 5 shows a flowchart of an example method 500 according to some example embodiments of the present disclosure. The method 500 can be implemented at the first device 110 as shown in Fig. 1. For the purpose of discussion, the method 500 will be described with reference to Fig. 1.

At block 510, the first device 110 transmits, to a second device 120, a first random access request comprising a first random access preamble and data. At block 520, the first device 110 receives an identification of the first random access preamble from the second device 120. At block 530, responsive to receiving the identification without a grant for retransmitting the data, the first device 110 ceases monitoring a response to the first random access request.

In some example embodiments, the method 500 further comprises: responsive to receiving the identification without the grant, transmitting to the second device 120 a second random access request comprising a second random access preamble and the data.

In some example embodiments, the first random access request is transmitted with a first power for the first random access preamble and a second power for the data, and wherein transmitting the second random access request comprises transmitting the second random access preamble with the first power and the data with the second power.

In some example embodiments, the first random access request is transmitted with a first power for the first random access preamble and a second power for the data, and wherein transmitting the second random access request comprises transmitting the second random access preamble with the first power and the data with a third power greater than the second power.

In some example embodiments, transmitting the data with the third power comprises: receiving from the second device 120 a power ramping indication indicating whether power ramping is to be performed for data transmission; and in accordance with a determination that the power ramping is to be performed for data transmission, transmitting the data with the third power.

In some example embodiments, transmitting the second random access request comprises: receiving, from the second device 120, a backoff indication along with the identification; and delaying transmission of the second random access request based on the backoff indication.

In some example embodiments, transmitting the second random access request comprises: determining a transport block size used to transmit the data comprised in the first random access request; and selecting, from a first set of random access preambles and at least a second set of random access preambles, the second random access preamble based on the determined transport block size, the first set of random access preambles corresponding to a plurality of transport block sizes for data transmission, and the second set of random access preambles corresponding to a single transport block size for data transmission.

In some example embodiments, the method 500 further comprises receiving, from the second device 120, a mode indication indicating a first random access mode or a different second random access mode, wherein the first random access request is transmitted based on the first random access mode and; and transmitting, to the second device 120, a third random access request based on the mode indication.

In some example embodiments, receiving the mode indication comprises: receiving the mode indication via system information broadcast; receiving the mode indication via a dedicated configuration for the first device 110; or receiving the mode indication along with the identification.

In some example embodiments, the first device 110 comprises a terminal device, and the second device 120 comprises a network device.

Fig. 6 shows a flowchart of an example method 600 according to some example embodiments of the present disclosure. The method 600 can be implemented at the second device 120 as shown in Fig. 1. For the purpose of discussion, the method 600 will be described with reference to Fig. 1.

At block 610, the second device 120 receives, from a first device 110, a first random access request comprising a first random access preamble and data. At block 620, responsive to receiving the first random access preamble and a failure in decoding the data, the second device 120 determines an identification of the first random access preamble. At block 630, the second device 120 transmits, to the first device 110, the identification without a grant for retransmitting the data.

In some example embodiments, the method 600 further comprises: receiving, from the first device 110, a second random access request comprising a second random access preamble and the data.

In some example embodiments, the first random access request is received with a first power for the first random access preamble and a second power for the data, and wherein receiving the second random access request comprises receiving the second random access preamble with the first power and the data with the second power.

In some example embodiments, the first random access request is received with a first power for the first random access preamble and a second power for the data, and wherein receiving the second random access request comprises receiving the second random access preamble with the first power and the data with a third power greater than the second power.

In some example embodiments, the method 600 further comprises: configuring a power ramping indication to indicate that power ramping is to be performed for data transmission; and transmitting, the power ramping indication to the first device 110.

In some example embodiments, the method 600 further comprises: transmitting, to the first device 110, a backoff indication along with the identification to enable the first device 110 to delay transmission of the second random access request based on the backoff indication.

In some example embodiments, the method 600 further comprises: transmitting, to the first device 110, a mode indication indicating a first random access mode or a different second random access mode, wherein the first random access request is received based on the first random access mode; and receiving, from the second device 120, a third random access request based on the mode indication.

In some example embodiments, transmitting the mode indication comprises: transmitting the mode indication via system information broadcast; transmitting the mode indication via a dedicated configuration for the first device 110; or transmitting the mode indication along with the identification.

In some example embodiments, an apparatus capable of performing the method 500 may comprise means for performing the respective steps of the method 500. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some example embodiments, the apparatus comprises: means for transmitting, at a first device to a second device, a first random access request comprising a first random access preamble and data; means for receiving an identification of the first random access preamble from the second device; and means for responsive to receiving the identification without a grant for retransmitting the data, ceasing monitoring a response to the first random access request.

In some example embodiments, the apparatus further comprises: means for responsive to receiving the identification without the grant, transmitting to the second device a second random access request comprising a second random access preamble and the data.

In some example embodiments, the first random access request is transmitted with a first power for the first random access preamble and a second power for the data, and wherein the means for transmitting the second random access request comprises means for transmitting the second random access preamble with the first power and the data with the second power.

In some example embodiments, the first random access request is transmitted with a first power for the first random access preamble and a second power for the data, and wherein the means for transmitting the second random access request comprises means for transmitting the second random access preamble with the first power and the data with a third power greater than the second power.

In some example embodiments, the means for transmitting the data with the third power comprises: means for receiving from the second device a power ramping indication indicating whether power ramping is to be performed for data transmission; and means for in accordance with a determination that the power ramping is to be performed for data transmission, transmitting the data with the third power.

In some example embodiments, the means for transmitting the second random access request comprises: means for receiving, from the second device, a backoff indication along with the identification; and means for delaying transmission of the second random access request based on the backoff indication.

In some example embodiments, the means for transmitting the second random access request comprises: means for determining a transport block size used to transmit the data comprised in the first random access request; and means for selecting, from a first set of random access preambles and at least a second set of random access preambles, the second random access preamble based on the determined transport block size, the first set of random access preambles corresponding to a plurality of transport block sizes for data transmission, and the second set of random access preambles corresponding to a single transport block size for data transmission.

In some example embodiments, the apparatus further comprises means for receiving, from the second device, a mode indication indicating a first random access mode or a different second random access mode, wherein the first random access request is transmitted based on the first random access mode and; and means for transmitting, to the second device, a third random access request based on the mode indication.

In some example embodiments, the means for receiving the mode indication comprises: means for receiving the mode indication via system information broadcast; means for receiving the mode indication via a dedicated configuration for the first device; or means for receiving the mode indication along with the identification.

In some example embodiments, the first device comprises a terminal device, and the second device comprises a network device.

In some example embodiments, an apparatus capable of performing the method 600may comprise means for performing the respective steps of the method 600. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some example embodiments, the apparatus comprises: means for means for receiving, from a first device at a second device, a first random access request comprising a first random access preamble and data; means for responsive to receiving the first random access preamble and a failure in decoding the data, determining an identification of the first random access preamble; and means for transmitting, to the first device, the identification without a grant for retransmitting the data.

In some example embodiments, the apparatus further comprises: means for receiving, from the first device, a second random access request comprising a second random access preamble and the data.

In some example embodiments, the first random access request is received with a first power for the first random access preamble and a second power for the data, and wherein the means for receiving the second random access request comprises means for receiving the second random access preamble with the first power and the data with the second power.

In some example embodiments, the first random access request is received with a first power for the first random access preamble and a second power for the data, and wherein the means for receiving the second random access request comprises means for receiving the second random access preamble with the first power and the data with a third power greater than the second power.

In some example embodiments, the apparatus further comprises: means for configuring a power ramping indication to indicate that power ramping is to be performed for data transmission; and means for transmitting, the power ramping indication to the first device.

In some example embodiments, the apparatus further comprises: means for transmitting, to the first device, a backoff indication along with the identification to enable the first device to delay transmission of the second random access request based on the backoff indication.

In some example embodiments, the apparatus further comprises: means for transmitting, to the first device, a mode indication indicating a first random access mode or a different second random access mode, wherein the first random access request is received based on the first random access mode; and means for receiving, from the second device, a third random access request based on the mode indication.

In some example embodiments, the means for transmitting the mode indication comprises: means for transmitting the mode indication via system information broadcast; means for transmitting the mode indication via a dedicated configuration for the first device; or means for transmitting the mode indication along with the identification.

Fig. 7 is a simplified block diagram of a device 700 that is suitable for implementing embodiments of the present disclosure. The device 700 may be provided to implement the communication device, for example the first device 110 or the second device 120 as shown in Fig. 1. As shown, the device 700 includes one or more processors 710, one or more memories 720 coupled to the processor 710, and one or more communication modules 740 coupled to the processor 710.

The communication module 740 is for bidirectional communications. The communication module 740 has at least one antenna to facilitate communication. The communication interface may represent any interface that is necessary for communication with other network elements.

The processor 710 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 700 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

The memory 720 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 724, an electrically programmable read only memory (EPROM) , a flash memory, a hard disk, a compact disc (CD) , a digital video disk (DVD) , and other magnetic storage and/or optical storage. Examples of the volatile memories include, but are not limited to, a random access memory (RAM) 722 and other volatile memories that will not last in the power-down duration.

A computer program 730 includes computer executable instructions that are executed by the associated processor 710. The program 730 may be stored in the ROM 720. The processor 710 may perform any suitable actions and processing by loading the program 730 into the RAM 720.

The embodiments of the present disclosure may be implemented by means of the program 730 so that the device 700 may perform any process of the disclosure as discussed with reference to Figs. 5 to 6. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

In some embodiments, the program 730 may be tangibly contained in a computer readable medium which may be included in the device 700 (such as in the memory 720) or other storage devices that are accessible by the device 700. The device 700 may load the program 730 from the computer readable medium to the RAM 722 for execution. The computer readable medium may include any types of tangible non-volatile storage, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. Fig. 8 shows an example of the computer readable medium 800 in form of CD or DVD. The computer readable medium has the program 730 stored thereon.

Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects 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. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method 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.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the

method

500 or 600 as described above with reference to Figs. 5-6. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

In the context of the present disclosure, the computer program codes or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , an optical fiber, a portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

Although the present disclosure has been described in languages specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

A first device comprising:

at least one processor; and

at least one memory including computer program codes;

the at least one memory and the computer program codes are configured to, with the at least one processor, cause the first device at least to:

transmit, to a second device, a first random access request comprising a first random access preamble and data;

receive an identification of the first random access preamble from the second device; and

responsive to receiving the identification without a grant for retransmitting the data, cease monitoring a response to the first random access request.
The first device of Claim 1, wherein the first device is further caused to:

responsive to receiving the identification without the grant, transmit to the second device a second random access request comprising a second random access preamble and the data.
The first device of Claim 2, wherein the first random access request is transmitted with a first power for the first random access preamble and a second power for the data, and

wherein the first device is caused to transmit the second random access preamble with the first power and the data with the second power.
The first device of Claim 2, wherein the first random access request is transmitted with a first power for the first random access preamble and a second power for the data, and

wherein the first device is caused to transmit the second random access preamble with the first power and the data with a third power greater than the second power.
The first device of Claim 4, wherein the first device is caused to transmit the data with the third power by:

receiving from the second device a power ramping indication indicating whether power ramping is to be performed for data transmission; and

in accordance with a determination that the power ramping is to be performed for data transmission, transmitting the data with the third power.
The first device of Claim 2, wherein the first device is caused to transmit the second random access request by:

receiving, from the second device, a backoff indication along with the identification; and

delaying transmission of the second random access request based on the backoff indication.
The first device of Claim 2, wherein the first device is caused to transmit the second random access request by:

determining a transport block size used to transmit the data comprised in the first random access request; and

selecting, from a first set of random access preambles and at least a second set of random access preambles, the second random access preamble based on the determined transport block size, the first set of random access preambles corresponding to a plurality of transport block sizes for data transmission, and the second set of random access preambles corresponding to a single transport block size for data transmission.
The first device of Claim 1, wherein the first device is further caused to:

receive, from the second device, a mode indication indicating a first random access mode or a different second random access mode, wherein the first random access request is transmitted based on the first random access mode and; and

transmit, to the second device, a third random access request based on the mode indication.
The first device of Claim 8, wherein the first device is caused to receive the mode indication by:

receiving the mode indication via system information broadcast;

receiving the mode indication via a dedicated configuration for the first device; or

receiving the mode indication along with the identification.
The first device of Claim 1, wherein the first device comprises a terminal device, and the second device comprises a network device.
A second device comprising:

at least one processor; and

at least one memory including computer program codes;

the at least one memory and the computer program codes are configured to, with the at least one processor, cause the second device at least to:

receive, from a first device, a first random access request comprising a first random access preamble and data; and

responsive to receiving the first random access preamble and a failure in decoding the data, determine an identification of the first random access preamble; and

transmit, to the first device, the identification without a grant for retransmitting the data.
The second device of Claim 11, wherein the second device is further caused to:

receive, from the first device, a second random access request comprising a second random access preamble and the data.
The second device of Claim 12, wherein the first random access request is received with a first power for the first random access preamble and a second power for the data, and

wherein the second device is caused to receive the second random access preamble with the first power and the data with the second power.
The second device of Claim 12, wherein the first random access request is received with a first power for the first random access preamble and a second power for the data, and

wherein the second device is caused to receive the second random access preamble with the first power and the data with a third power greater than the second power.
The second device of Claim 14, wherein the second device is further caused to:

configure a power ramping indication to indicate that power ramping is to be performed for data transmission; and

transmit, the power ramping indication to the first device.
The second device of Claim 12, wherein the second device is further caused to:

transmit, to the first device, a backoff indication along with the identification to enable the first device to delay transmission of the second random access request based on the backoff indication.
The second device of Claim 11, wherein the second device is further caused to:

transmit, to the first device, a mode indication indicating a first random access mode or a different second random access mode, wherein the first random access request is received based on the first random access mode; and

receive, from the second device, a third random access request based on the mode indication.
The second device of Claim 17, wherein the second device is caused to transmit the mode indication by:

transmitting the mode indication via system information broadcast;

transmitting the mode indication via a dedicated configuration for the first device; or

transmitting the mode indication along with the identification.
The second device of Claim 11, wherein the first device comprises a terminal device, and the second device comprises a network device.
A method comprising:

transmitting, at a first device to a second device, a first random access request comprising a first random access preamble and data;

receiving an identification of the first random access preamble from the second device; and

responsive to receiving the identification without a grant for retransmitting the data, ceasing monitoring a response to the first random access request.
The method of Claim 1, further comprising:

responsive to receiving the identification without the grant, transmitting to the second device a second random access request comprising a second random access preamble and the data.
The method of Claim 21, wherein the first random access request is transmitted with a first power for the first random access preamble and a second power for the data, and

wherein transmitting the second random access request comprises transmitting the second random access preamble with the first power and the data with the second power.
The method of Claim 21, wherein the first random access request is transmitted with a first power for the first random access preamble and a second power for the data, and

wherein transmitting the second random access request comprises transmitting the second random access preamble with the first power and the data with a third power greater than the second power.
The method of Claim 23, wherein transmitting the data with the third power comprises:

receiving from the second device a power ramping indication indicating whether power ramping is to be performed for data transmission; and

in accordance with a determination that the power ramping is to be performed for data transmission, transmitting the data with the third power.
The method of Claim 21, wherein transmitting the second random access request comprises:

receiving, from the second device, a backoff indication along with the identification; and

delaying transmission of the second random access request based on the backoff indication.
The method of Claim 21, wherein transmitting the second random access request comprises:

determining a transport block size used to transmit the data comprised in the first random access request; and

selecting, from a first set of random access preambles and at least a second set of random access preambles, the second random access preamble based on the determined transport block size, the first set of random access preambles corresponding to a plurality of transport block sizes for data transmission, and the second set of random access preambles corresponding to a single transport block size for data transmission.
The method of Claim 20, further comprising:

receiving, from the second device, a mode indication indicating a first random access mode or a different second random access mode, wherein the first random access request is transmitted based on the first random access mode and; and

transmitting, to the second device, a third random access request based on the mode indication.
The method of Claim 27, wherein receiving the mode indication comprises:

receiving the mode indication via system information broadcast;

receiving the mode indication via a dedicated configuration for the first device; or

receiving the mode indication along with the identification.
The method of Claim 20, wherein the first device comprises a terminal device, and the second device comprises a network device.
A method comprising:

receiving, from a first device at a second device, a first random access request comprising a first random access preamble and data; and

responsive to receiving the first random access preamble and a failure in decoding the data, determining an identification of the first random access preamble; and

transmitting, to the first device, the identification without a grant for retransmitting the data.
The method of Claim 30, further comprising:

receiving, from the first device, a second random access request comprising a second random access preamble and the data.
The method of Claim 31, wherein the first random access request is received with a first power for the first random access preamble and a second power for the data, and

wherein receiving the second random access request comprises receiving the second random access preamble with the first power and the data with the second power.
The method of Claim 31, wherein the first random access request is received with a first power for the first random access preamble and a second power for the data, and

wherein receiving the second random access request comprises receiving the second random access preamble with the first power and the data with a third power greater than the second power.
The method of Claim 33, further comprising:

configuring a power ramping indication to indicate that power ramping is to be performed for data transmission; and

transmitting, the power ramping indication to the first device.
The method of Claim 31, further comprising:

transmitting, to the first device, a backoff indication along with the identification to enable the first device to delay transmission of the second random access request based on the backoff indication.
The method of Claim 30, further comprising:

transmitting, to the first device, a mode indication indicating a first random access mode or a different second random access mode, wherein the first random access request is received based on the first random access mode; and

receiving, from the second device, a third random access request based on the mode indication.
The method of Claim 36, wherein transmitting the mode indication comprises:

transmitting the mode indication via system information broadcast;

transmitting the mode indication via a dedicated configuration for the first device; or

transmitting the mode indication along with the identification.
The method of Claim 30, wherein the first device comprises a terminal device, and the second device comprises a network device.
An apparatus comprising:

means for transmitting, at a first device to a second device, a first random access request comprising a first random access preamble and data;

means for receiving an identification of the first random access preamble from the second device; and

means for responsive to receiving the identification without a grant for retransmitting the data, ceasing monitoring a response to the first random access request.
An apparatus comprising:

means for receiving, from a first device at a second device, a first random access request comprising a first random access preamble and data;

means for responsive to receiving the first random access preamble and a failure in decoding the data, determining an identification of the first random access preamble; and

means for transmitting, to the first device, the identification without a grant for retransmitting the data.
A non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method of any of claims 20-29.
A non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method of any of claims 30-38.