WO2021042394A1

WO2021042394A1 - Sequence repetition for unsynchronized uplink transmission

Info

Publication number: WO2021042394A1
Application number: PCT/CN2019/104798
Authority: WO
Inventors: Emad Farag; Matha DEGHEL; Frank Frederiksen; Zexian Li; Chunhai Yao; Juha Korhonen
Original assignee: Nokia Shanghai Bell Co., Ltd.; Nokia Solutions And Networks Oy; Nokia Technologies Oy
Priority date: 2019-09-06
Filing date: 2019-09-06
Publication date: 2021-03-11
Also published as: CN114342446B; CN114342446A

Abstract

According to embodiments of the present disclosure, the network device transmits information indicating the structure of uplink signal to the terminal device. The information indicates that a length of a cyclic prefix and a length of a sequence in one symbol is the same. The cyclic prefix repeats the sequence. In this way, a common frequency-domain transformation is suitable for all terminal devices, which simplifies the receiver processing at the network device. Further, allocation of the PUSCH occasions is more efficient.

Description

SEQUENCE REPETITION FOR UNSYNCHRONIZED UPLINK TRANSMISSION

FIELD

Embodiments of the present disclosure generally relate to the field of communications, in particular, to a method, device, apparatus and computer readable storage medium for sequence repetition for unsynchronized uplink transmission.

BACKGROUND

Recently, several technologies have been proposed to improve communication performances. Generally, the network device is configured to process the signal in frequency domain. The network device is usually able to process signals from synchronized terminal devices. However, in some situations, the terminal devices may not be synchronized. Thus, study on unsynchronized reception is needed.

SUMMARY

In general, example embodiments of the present disclosure provide a solution for sequence repetition for unsynchronized uplink transmission and corresponding communication devices.

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 configuration of an uplink transmission. The configuration indicates that a length of a cyclic prefix is to be same as a length of a sequence in one symbol. The first device is further caused to receive from the second device a signal generated based on the configuration. The first device is also caused to perform a frequency-domain transformation on the signal.

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 configuration of an uplink transmission. The configuration indicates that a length of a cyclic prefix is to be same as a length of a sequence in one symbol. The second device is also caused to generate a signal based on the configuration. The second device is further caused to transmit the signal to the first device.

In a third aspect, there is provided a method. The method comprises transmitting, at a first device and to a second device, a configuration of an uplink transmission. The configuration indicates that a length of a cyclic prefix is to be same as a length of a sequence in one symbol. The method also comprises receiving, from the second device, a signal generated based on the configuration. The method further comprises performing a frequency-domain transformation on the signal.

In a fourth aspect, there is provided a method. The method comprises receiving, at a second device and from a first device, a configuration of an uplink transmission. The configuration indicates that a length of a cyclic prefix is to be same as a length of a sequence in one symbol. The method also comprises generating a signal based on the configuration. The method further comprises transmitting the signal to the first device.

In a fifth aspect, there is provided an apparatus. The apparatus comprises means for transmitting, at a first device and to a second device, a configuration of an uplink transmission, the configuration indicating that a length of a cyclic prefix is to be same as a length of a sequence in one symbol; means for receiving, from the second device, a signal generated based on the configuration; and means for performing a frequency-domain transformation on the signal.

In a sixth aspect, there is provided an apparatus. The apparatus comprises means for receiving, at a second device and from a first device, a configuration of an uplink transmission, the configuration indicating that a length of a cyclic prefix is to be same as a length of a sequence in one symbol; means for generating a signal based on the configuration; and means for transmitting the signal to the first device.

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 any one of the above fourth to sixth aspects.

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 a schematic diagram of uplink slots according to conventional technologies;

Fig. 2 illustrates a schematic diagram of physical uplink shared channel (PUSCH) occasions according to conventional technologies;

Fig. 3 illustrates an example communication network in which embodiments of the present disclosure may be implemented;

Fig. 4 illustrates a schematic diagram of interactions among communication devices according to embodiments of the present disclosure;

Fig. 5 illustrates a schematic diagram of a structure of an uplink signal according to embodiments of the present disclosure;

Fig. 6 illustrates a schematic diagram of physical uplink shared channel (PUSCH) occasions according to embodiments of the present disclosure;

Fig. 7 illustrates a schematic diagram of time windows for Fast-Fourier-Transform according to embodiments of the present disclosure;

Fig. 8 illustrates a schematic diagram of time windows for Fast-Fourier-Transform according to embodiments of the present disclosure;

Fig. 9 illustrates a schematic diagram of time windows for Fast-Fourier-Transform according to embodiments of the present disclosure;

Fig. 10 illustrates a schematic diagram of time windows for Fast-Fourier-Transform according to embodiments of the present disclosure;

Fig. 11 illustrates a flowchart of a method implemented at a network device according to embodiments of the present disclosure;

Fig. 12 illustrates a flowchart of a method implemented at a terminal device according to embodiments of the present disclosure;

Fig. 13 illustrates a simplified block diagram of a device that is suitable for implementing embodiments of the present disclosure; and

Fig 14 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) , New Radio (NR) , Non-terrestrial network (NTN) 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, 2.95G, 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, 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.

As mentioned above, study on unsynchronized reception is needed. For example, two-step random access channel (RACH) has been proposed. In two-step RACH, MsgA combines the preamble signal (Msg1 in four-step RACH) and the data signal (Msg3 in four-step RACH) , and MsgB combines the random access response (Msg2 in four-step RACH) and the contention resolution (Msg4 in four-step RACH) . The two-step RACH may be required to operate in a cell with any cell size and the two-step RACH should be able to operate regardless of whether the terminal device has a valid Timing Advance (TA) or not.

When the terminal device is unsynchronized (that is, it doesn’t have a valid uplink TA) , the MsgA is transmitted without any timing advance and the arrival time of the MsgA at the network device depends on the round-trip delay. As shown in Fig. 1, the signal 110 which is from a terminal device located close to the network device arrives with zero or very small time delay relative to the network device reference time. The signal 120 which is from a terminal device located at the cell edge arrives with a large time delay relative to the network device reference time. The time delay 130 in this case is equal to the maximum round-trip delay which depends on the cell radius. Only as an example, for a cell with a radius 100 km, the difference between the time of arrival of the signal of the earliest terminal located close to the network device and that of the latest terminal device is 667 μsec. For a system with 15 kHz subcarrier spacing (SCS) , this corresponds to fewer than 10 OFDM symbols. Any terminal device within the cell has an arrival time between 0 and 667 μsec.

Due to the large delay difference, it may require separate front-end FFT processing for each terminal device. Further, in case of several time division multiplexed PUSCH Occasions for MsgA, a large guard period is inserted between each PUSCH Occasion and the next PUSCH Occasion to account for the difference in time of arrival between the earliest and latest UE signal within the cell, which reduces the overall efficiency.

Generally speaking, if the terminal devices are time synchronized at the network device, a single front-end FFT is used for all terminal devices. However, if the terminal devices are unsynchronized, i.e. with signals arriving with different delays that exceed the CP duration, a common FFT can no longer be used. Instead, multiple FFTs are required with each FFT covering an arrival time window not exceeding the CP duration. In the most extreme case, if arrival time of each terminal device signal is different from that of other terminal devices by a duration that exceeds the CP duration, each terminal device may require separate FFT processing and would still potentially suffer from inter-symbol and inter-carrier interference causing loss of orthogonality from the other terminal device transmissions.

An alternative to having separate FFT processing is to filter each terminal device’s signal at the network device, to advance the terminal device by a time equal to the delay of the terminal device’s signal, and then to add the terminal device’s signal again to the received signal. After that a common FFT can be used for all the terminal devices. However, the filtering and time advance processing for each terminal device’s signal to align its timing to the reference time of the network device increases the computational complexity of the network device. Further, such approach may not be able to fully compensate for loss of orthogonality, since signals are received out of synchronized to each other.

A second issue with a long round trip delay is that a guard period should exist after each time domain PUSCH occasion, where the guard period is at least as long as the round-trip delay. This reduces the overall efficiency of the MsgA PUSCH. Fig. 2 shows PUSCH Occasions with a guard period in between. For example, a cell with a cell radius of 75 km, which corresponds to RTT of 500 μsec has a guard period of 7 OFDM symbols with 15 kHz SCS. If the duration of MsgA PUSCH is also 7 OFDM symbols, the efficiency of the MsgA PUSCH transmission is 50%after accounting for the guard period.

Another method for handling uplink transmissions from the terminal devices with large RTT and without a valid TA is that the terminal device applies a timing adjustment based on downlink measurements of reference signal receiving power (RSRP) . However, it is inaccurate as there can be large variation in the RSRP for the same terminal device -to-network device distance due to shadowing and fading effects.

Alternatively, the network device can estimate the timing offset of uplink transmission by processing the MsgA preamble. Based on the timing offset estimation, the network device can perform timing adjustment and/or terminal device grouping. Multiple processing time windows can be applied to terminal device groups characterized by different range of timing offsets. However, it increases the gNB computation complexity. Thus, new mechanism for unsynchronized uplink transmission is needed.

Principle and embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Reference is first made to Fig. 3, which illustrates an example communication system 300 in which embodiments of the present disclosure may be implemented.

Fig. 3 illustrates a schematic diagram of a communication system 300 in which embodiments of the present disclosure can be implemented. The link from the first device 310 to the second devices 320 may be referred to as the “downlink” and the link from the second devices 320 to the first device 310 may be referred to as the “uplink” . The procedures which are described to be implemented at the terminal device may also be able to be implemented at the network device and the procedures which are described to be implemented at the network device may also be able to be implemented at the terminal device. For the purpose of illustrations, the first device 310 hereinafter refers to the network device 310 and the second device 320 hereinafter refers to the terminal device.

The communication system 300, which is a part of a communication network, comprises terminal devices 320-1, 32-2, ..., 320-N (collectively referred to as “terminal device (s) 320” where N is an integer number) . The communication system 300 comprises a network device 310. The terminal devices 320 and the network device 310 can communicate with each other.

It should be understood that the communication system 300 may also comprise other elements which are omitted for the purpose of clarity. It is to be understood that the numbers of terminal devices and network devices shown in Fig. 3 are given for the purpose of illustration without suggesting any limitations.

It is to be understood that the number of network devices and terminal devices is only for the purpose of illustration without suggesting any limitations. The system 300 may include any suitable number of network devices and terminal devices adapted for implementing embodiments of the present disclosure.

Communications in the communication system 300 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) , Discrete Fourier Transform spread OFDM (DFT-s-OFDM) and/or any other technologies currently known or to be developed in the future.

Fig. 4 illustrates a schematic diagram of interactions 400 in accordance with embodiments of the present disclosure. The interactions 400 may be implemented at any suitable devices. Only for the purpose of illustrations, the interactions 400 are described to be implemented at the terminal device 320-1 and the network device 310.

In some embodiments, the network device 310 may determine 4005 a configuration of uplink transmission. For example, if a certain random access procedure is trigger, the network device may determine the configuration of the uplink transmission. The certain random access procedure may refer to a two-step RACH. It should be noted that the other suitable system operations may also cause the network device 310 to determine the configuration. The configuration of uplink transmission introduces an extreme cyclic prefix and provides symbol interlacing to facilitate operation in situations with requirements for large values of time misalignment of transmissions. The configuration indicates that a length of a cyclic prefix is the same as a length of the sequence in one symbol.

Fig. 5 shows an example of a symbol structure 500 of the uplink signal. The symbol comprises a cyclic prefix 5010 and a sequence 5020. The length of the cyclic prefix 5010 (represented as N_CP) is equal to the length of the sequence 5020 (represented as N _seq) . In this way, the sequence 5020 is duplicated and repeated, thereby effectively creating an extremely long cyclic prefix. In some embodiments, the structure 500 may be applicable to some specific operations while normal operations may be using the standard configuration for cyclic prefix.

The network device 310 transmits 4010 the configuration to the terminal device 320-1. In some embodiments, if the two-step RACH is triggered, the network device 310 may transmit the configuration. In some embodiments, the network device 310 may configure the PUSCH occasions for monitoring the signal. Fig. 6 shows an example structure 600 of the PUSCH occasion. The network device 310 may configure consecutive PUSCH occasions, for example, the PUSCH occasions 6010-1, 6010-2 and 6010-3. As shown in Fig. 6, there is no gap between the PUSCH occasions. The network device 310 may configure a gap at the end of the consecutive PUSCH occasions, for example, the gap 6020. In some embodiments, the duration of gap 6020 may be equal to the maximum round trip delay within the cell. Alternatively, the duration of gap 6020 may be larger than the maximum round trip delay. In this way, the efficiency has been improved, as there is a single gap at the end of a group of PUSCH occasions, rather than a gap after each PUSCH occasion. It should be noted that the number of PUSCH occasions and gap shown in Fig. 6 is only an example. The network device 310 may configure any suitable number of PUSCH occasions.

The terminal device 320-1 generates 4015 the signal based on the configuration. The length of cyclic prefix and the length of the sequence in the signal are equal to each other. The terminal device 320-1 transmits 4020 the signal to the network device 310.

The network device 310 performs the frequency domain transformation 4030 of the signal. In some embodiments, the network device 310 may generate a set of time windows for the frequency-domain transformation. For example, the frequency-domain transformation may be Fast Fourier transformation (FFT) . Alternatively, the frequency-domain transformation may be a discrete fast Fourier transformation. It should be noted that the frequency domain transformation may be any suitable transformation. Only for the purpose of illustrations, the frequency-domain transformation may refer to the FFT hereinafter. The length of the time window may be equal to the length of the cyclic prefix and the sequence. The network device 310 may determine at least one target time window for the signal based on a delay of the terminal device 320-1. The term “window” used herein refers to a duration where a portion of signal is taken. The network device 310 may take the portion of the signal during the time window and perform the frequency domain transformation on the portion of the signal. Embodiments of the processing are described with the reference to Figs. 7-10.

As shown in Fig. 7, the network device 310 generates a set of time windows, the time windows 7010-0, 7010-1, 7010-2, 7010-3, 7010-4, 7010-5, 7010-6, 7010-7 and 7010-8. It should be noted that the number of time windows is only for the purpose of illustrations. The signal 710 shown in Fig. 7 may be received from the terminal device 320-1 and the signal 720 may be received from the terminal device 320-2. As shown in Fig. 7, for each symbol, there are two parts, the cyclic prefix and the sequence. The signal 710 comprises the symbol 7100 including the cyclic prefix 7100-1 and the sequence 7100-2, the symbol 7101 including the cyclic prefix 7101-1 and the sequence 7101-2, the symbol 7102 including the cyclic prefix 7102-1 and the sequence 7102-2 and the symbol 7103 including the cyclic prefix 7103-1 and the sequence 7103-2. The signal 720 comprises the symbol 7200 including the cyclic prefix 7200-1 and the sequence 7200-2, the symbol 7201 including the cyclic prefix 7201-1 and the sequence 7201-2, the symbol 7202 including the cyclic prefix 7202-1 and the sequence 7201-2, and the symbol 7203 including the cyclic prefix 7203-1 and the sequence 7203-2. It should be noted that the signal may comprise any suitable number of symbols.

Assuming that the time window starting at the base station reference time is time window 7010-0, the target time windows for processing the signal 710 are determined based on the delay of the terminal device 320-1 as below:

where N _Delay is the estimated time delay from preamble detection for the terminal device 320-u, and %is the modulo operator.

For example, the time window 7010-1 overlaps with the symbol 7100. As mentioned above, the lengths of the cyclic prefix 7100-1 and the sequence 7100-2 are same and the cyclic prefix 7100-1 is duplicated from the sequence 7100-2. Further, since the length of the time window 7010-1 is the same as the sequence 7100-2, the portions of the symbol 7100 overlapped with the time window 7010-1 comprises all information carried in the sequence 7100-2. Thus, the time window 7010-1 may be determined to be the target time window for processing the symbol 7100. The network device 310 may obtain the portion of the symbol 7100 during the time window 7010-1 and perform the FFT on the obtained portion. Similarly, the time windows 7010-3, 7010-5 and 7010-7 may be used for processing the

symbols

7101, 7102 and 7103, respectively. The time windows 7010-2, 7010-4, 7010-6 and 7010-8 may be used for processing the

symbols

7200, 7201, 7202 and 7203, respectively. In other words, the determination of even or odd time window is based on the fact that the time window selected should overlap with cyclic prefix/sequence of the same OFDM symbol.

As mentioned above, in some embodiments, the network device 310 may configure consecutive PUSCH occasions without inserting guard periods between the consecutive PUSCH occasions. In this situation, the same time window can correspond to symbols in different PUSCH occasions as shown in Fig. 8. As shown in Fig. 8, there are consecutive PUSCH occasions 801-1 and 801-2. The signal 810 is from the terminal device 320-1, the signal 820 is from the terminal device 320-2, the signal 830 is from the terminal device 320-3 (not shown) and the signal 840 is from the terminal device 320-4 (not shown) . In Fig. 8, the second time window 803 in the PUSCH occasion 801-2 may be used for the symbol 8023 which includes the cyclic prefix 8023-1 and the sequence 8023-2 and the symbol 8040 which includes the cyclic prefix 8040-1 and the sequence 8040-2.

In some embodiments, the network device 310 may receive multi-path signals. For example, as shown in Fig. 9, the

signals

910 and 920 are both from the terminal device 320-1. The

signals

910 and 920 are the multi-path signals of the terminal device 320-1. The set of time windows 901 comprises the time windows 9010-0, 9010-1, 9010-2 and 9010-3. The time windows 9010-0, 9010-2 and 9010-4 may be used for the signal 910 and the time windows 9010-1 and 9010-3 may be used for the signal 920. The set of time windows 901 may not provide ideal reception as the delay spread 930 between the signal 910 and the signal 920 goes over the time window borders. The network device 310 may compare a delay spread 930 between the signal 910 and the signal 920 with the length of the cyclic prefix. If the delay spread 930 is less than half of the length of the cyclic prefix, in order to overcome the significant delay spread 930, the network device 310 may determine a further set of time windows 902 comprising the time windows 9020-0, 9020-1, 9020-2, 9020-3 and 9020-4. The offset between the window 9010-0 and the window 9020-0 may be half of the window. The further set of time windows 902 may be used for processing the

signals

910 and 920 since the delay spread 930 is less than half of the CP or FFT window length. For example, the time window 9020-1 would fully overlap with both symbols 9100 and 9200 and would then be used for ideal reception of the first symbol.

Alternatively or in addition, to cope with significant delay spread when one multi-path of a terminal device’s signal is in the even window, and another multi-path of the same terminal device’s signal is in the odd window, if the network device 310 determines that the target windows of the signal and the further signal are different, the network device 310 may obtain a portion of the signal and a further portion of the further signal from the different time windows. The network device 310 may perform the frequency-domain transformation on the portion of the signal and the further portion of the further signal and combine the transformed portion and the transformed further portion after delay alignment between the further signal and the signal.

In some embodiments, if the maximum round trip time is small, two time windows can be used for the same symbol. As show in Fig. 10, the signal 1010 is from the terminal device 320-1 with zero round-trip time and the signal 1020 is from the terminal device 320-2 with the maximum round-trip time. Since the maximum round trip time is below threshold time, as shown in Fig. 10, the time windows 10002-1 and 10001-1 can be used for the symbol 10010 including the cyclic prefix 10010-1 and the sequence 10010-2, the time windows 10002-2 and 10001-2 can be used for the symbol 10011 including the cyclic prefix 10011-1 and the sequence 10011-2, the time windows 10002-3 and 10001-3 can be used for the symbol 10012 including the cyclic prefix 10012-1 and the sequence 10012-2. Similarly, the time windows 10002-1 and 10001-1 can be used for the symbol 10020 including the cyclic prefix 10020-1 and the sequence 10020-2, the time windows 10002-2 and 10001-2 can be used for the symbol 10021 including the cyclic prefix 10021-1 and the sequence 10021-2, the time windows 10002-3 and 10001-3 can be used for the symbol 10022 including the cyclic prefix 10022-1 and the sequence 10022-2. Further, even though the time windows 10002-1 and 10001-1 can be used for the symbol 10010, the time windows 10002-1 and 10001-1 are used for different portions of the symbol. The network device 310 may perform the frequency domain on the different portions of the symbol and combine the transformed different portions of the symbol. In this way, using two time windows for the same symbol with different samples can improve the reception reliability.

Alternatively or in addition, the network device 310 may generate two sets of windows. For example, the network device 310 may generate the set of time windows 700 shown in Fig. 7 and generate a further set of time windows that are slightly shifted from the even time windows in the set of time windows 700. In this way, it may provide improved detection reliability for terminal devices with short round trip time (reception according to Fig. 10) while reception for terminal devices with large round trip time would be according to Fig. 7.

Fig. 11 shows a flowchart of an example method 1100 implemented at a network device in accordance with some embodiments of the present disclosure. The method 1100 may be implemented at any suitable devices. For the purpose of discussion, the method 1100 will be described from the perspective of the network device 310 with reference to Fig. 3.

At block 1110, the network device 310 transmits the configuration of an uplink transmission. For example, if a certain random access procedure is trigger, the network device may determine the configuration of the uplink transmission. The certain random access procedure may refer to a two-step RACH. It should be noted that the other suitable system operations may also cause the network device 310 to determine the configuration. The configuration of uplink transmission introduces an extreme cyclic prefix and provides symbol interlacing to facilitate operation in situations with requirements for large values of time misalignment of transmissions. The configuration indicates that a length of a cyclic prefix is to be the same as a length of the sequence in one symbol. In some embodiments, if the two-step RACH is triggered, the network device 310 may transmit the configuration.

At block 1120, the network device 310 receives the signal which is generated based on the configuration. In some embodiments, the network device 310 may configure the PUSCH occasions for monitoring the signal. The network device 310 may configure consecutive PUSCH occasions, which means that there is no gap between the PUSCH occasions. The network device 310 may configure a gap at the end of the consecutive PUSCH occasions. In some embodiments, the duration of gap may be equal to the maximum round trip delay within the cell. Alternatively, the duration of gap may be larger than the maximum round trip delay.

At block 1130, the network device 310 performs the frequency-domain transforming on the signal. In some embodiments, the network device 310 may generate a set of time windows for the frequency-domain transformation. For example, the frequency-domain transformation may be Fast Fourier transformation (FFT) . Alternatively, the frequency-domain transformation may be a discrete fast Fourier transformation. It should be noted that the frequency domain transformation may be any suitable transformation. Only for the purpose of illustrations, the frequency-domain transformation may refer to the FFT hereinafter. The length of the time window may be equal to the length of the cyclic prefix or the sequence. The network device 310 may determine at least one target time window for the signal based on a delay of the terminal device 320-1. The network device 310 may take the portion of the signal during the time window and perform the frequency domain transformation on the portion of the signal.

In some embodiments, the network device 310 may receive a further signal from the terminal device 320-1. The further signal and the signal are multi-path signals of the terminal device 320-1. If the even time windows in the set of time windows are used for processing the signal and the odd time windows in the set of time windows are used for processing the further signal, the network device 310 may generate a further set of time window for processing the signals.

Alternatively or in addition, the network device 310 may utilize the set of time windows for processing the signal and the further signal. The network device 310 may perform the frequency-domain transformation on the portion of the signal and the further portion of the further signal. The network device 310 may combine the transformed signal and the transformed further signal after delay alignment between the further signal and the signal.

In some embodiments, the network device 310 may determine that the target time window for the signal is different from the further target time window for the further signal. The network device 310 may obtain a portion of the signal during the target time window (for example, the even window) and a further portion of the further signal during the further target window (for example, the odd window) . The network device 310 may perform the frequency-domain transformation on the portion of the signal and the further portion of the further signal. The network device 310 may combine the transformed signal and the transformed further signal after delay alignment between the further signal and the signal.

In other embodiments, if the round trip delay is smaller than a threshold delay, the network device 310 may use two sets of time windows for processing the signal. For example, two time windows may be used for processing one symbol in the signal. More specifically, the network device 310 may obtain a first portion of the signal during the set of time windows and a second portion of the signal during the further set of windows. The first and second portions belong to one symbol in the signal. The network device 310 may perform the frequency-domain transformation on the first and second portions of the signal and combine the transformed first and second portions and the further portion of the signal.

Fig. 12 shows a flowchart of an example method 1200 implemented at a terminal device in accordance with some embodiments of the present disclosure. The method 1200 may be implemented at any suitable devices. For the purpose of discussion, the method 1200 will be described from the perspective of the terminal 320-1 with reference to Fig. 3.

At block 1210, the terminal device 320-1 receives the configuration of an uplink traffic. For example, if a certain random access procedure is trigger, the network device may determine the configuration of the uplink transmission. The certain random access procedure may refer to a two-step RACH. It should be noted that the other suitable system operations may also cause the network device 310 to determine the configuration. The configuration of uplink transmission introduces an extreme cyclic prefix and provides symbol interlacing to facilitate operation in situations with requirements for large values of time misalignment of transmissions. The configuration indicates that a length of a cyclic prefix is to be the same as a length of the sequence in one symbol. In some embodiments, if the two-step RACH is triggered, the network device 310 may transmit the configuration.

At block 1220, the terminal device 320-1 generates the signal based on the configuration. In some embodiments, if the two-step RACH is triggered, the terminal device 320-1 generates the signal based on the configuration. In some embodiments, the terminal device 320-1 may obtain the length of the cyclic prefix and the length of the sequence from the configuration. The terminal device 320-1 may generate the cyclic prefix portion by duplicating the sequence.

At block 1230, the terminal device 320-1 transmits the signal to the network device 310. For example, the signal may be transmitted on the PUSCH.

In some embodiments, an apparatus for performing the method 1100 (for example, the network device 310) may comprise respective means for performing the corresponding steps in the method 1100. These means may be implemented in any suitable manners. For example, it can be implemented by circuitry or software modules.

In some embodiments, the apparatus comprises means for transmitting, from a first device and to a second device, a configuration of an uplink transmission, the configuration indicating that a length of a cyclic prefix is to be same as a length of a sequence in one symbol; means for receiving, from the second device, a signal generated based on the configuration; and means for performing a frequency-domain transformation on the signal.

In some embodiments, the means for transmitting the configuration of uplink transmission comprises: means for in accordance with a determination that a random access procedure is triggered, transmitting the configuration of uplink transmission.

In some embodiments, the random access procedure comprises a two-step random access procedure.

In some embodiments, the means for performing a frequency-domain transforming on the signal comprises means for generating a set of time windows for Fast-Fourier-Transform, a length of one from the set of time windows being same as the length of the cyclic prefix; and means for determining at least one target time window for processing the signal based on overlapping between the set of time windows and the signal.

In some embodiments, the apparatus further comprises means for receiving a further signal from the second device, the further signal and the signal being multi-path signals of the second device; means for comparing a delay spread between the signal and the further signal with the length of cyclic prefix; and means for in accordance with a determination that the delay spread is less than half of the length of the cyclic prefix, generating a further set of time windows for processing the signal and the further signal.

In some embodiments, the apparatus further comprises means for receiving a further signal from the second device; means for in accordance with a determination that the target time window for the signal and a further target time window for the further signal are different, obtaining a portion the signal during the target time window and a further portion of the further signal during the further target time window; means for performing the frequency-domain transformation on the portion of the signal and the further portion of the further signal; and means for combining the transformed portion of the signal and the transformed further portion of the further signal after delay alignment between the further signal and the signal.

In some embodiments, the apparatus further comprises means for comparing a round trip delay between the first and second devices being less than a threshold delay; means for in accordance with a determination that the round trip delay is less than the threshold delay, generating a further set of windows; means for obtaining a first portion of the signal during the set of time windows and a second portion of the signal during the further set of windows; means for performing the frequency-domain transformation on the first and second portions of the signal; and means for combining the transformed first and second portions of the signal.

In some embodiments, the apparatus further comprises means for configuring a set of physical uplink shared channel (PUSCH) occasions for monitoring the signal, the set of PUSCH occasions being lack of gaps between each other; and means for configuring a gap at the end of the set of PUSCH occasions, a duration of the gap being no smaller than a round trip delay between the first and second devices.

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

In some embodiments, the frequency-domain transformation comprises a fast Fourier transform.

In some embodiments, the apparatus comprises means for receiving, at a second device and from a first device, a configuration of an uplink transmission, the configuration indicating that a length of a cyclic prefix is to be same as a length of a sequence in one symbol; means for generating a signal based on the configuration; and means for transmitting the signal to the first device.

In some embodiments, the means for generating the signal comprises: means for generating the cyclic prefix by duplicating the sequence.

In some embodiments, the means for receiving the configuration of uplink transmission comprises: means for in accordance with a determination that a random access procedure is triggered, receiving the configuration of uplink transmission.

Fig. 13 is a simplified block diagram of a device 1300 that is suitable for implementing embodiments of the present disclosure. The device 1300 may be provided to implement the communication device, for example the network device 310 or the terminal device 320-1 as shown in Fig. 3. As shown, the device 1300 includes one or more processors 1310, one or more memories 1320 coupled to the processor 1310, and one or more communication module (for example, transmitters and/or receivers (TX/RX) ) 1340 coupled to the processor 1310.

The communication module 1340 is for bidirectional communications. The communication module 1340 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 1310 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 1300 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 1320 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) 1324, 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) 1322 and other volatile memories that will not last in the power-down duration.

A computer program 1330 includes computer executable instructions that are executed by the associated processor 1310. The program 1330 may be stored in the ROM 1324. The processor 1310 may perform any suitable actions and processing by loading the program 1330 into the RAM 1322.

The embodiments of the present disclosure may be implemented by means of the program 1330 so that the device 1300 may perform any process of the disclosure as discussed with reference to Figs. 4 to 10. 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 1330 may be tangibly contained in a computer readable medium which may be included in the device 1300 (such as in the memory 1320) or other storage devices that are accessible by the device 1300. The device 1300 may load the program 1330 from the computer readable medium to the RAM 1322 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. 14 shows an example of the computer readable medium 1400 in form of CD or DVD. The computer readable medium has the program 1330 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 methods 500-700 and interactions as described above with reference to Figs. 2-8. 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 to:

transmit, to a second device, a configuration of an uplink transmission, the configuration indicating that a length of a cyclic prefix is to be same as a length of a sequence in one symbol;

receive, from the second device, a signal generated based on the configuration; and

perform a frequency-domain transformation on the signal.
The first device of claim 1, wherein the first device is caused to transmit the configuration of uplink transmission by:

in accordance with a determination that a random access procedure is triggered, transmitting the configuration of uplink transmission.
The first device of claim 2, wherein the random access procedure comprises a two-step random access procedure.
The first device of claim 1, wherein the first device is caused to perform a frequency-domain transforming on the signal by:

generating a set of time windows for the frequency-domain transformation, a length of one from the set of time windows being same as the length of the cyclic prefix; and

determining at least one target time window for processing the signal based on overlapping between the set of time windows and the signal.
The first device of claim 4, wherein the first device is further caused to:

receive a further signal from the second device, the further signal and the signal being multi-path signals of the second device;

compare a delay spread between the signal and the further signal with the length of cyclic prefix; and

in accordance with a determination that the delay spread is less than half of the length of the cyclic prefix, generate a further set of time windows for processing the signal and the further signal.
The first device of claim 4, wherein the first device is further caused to:

receive a further signal from the second device, the further signal and the signal being multi-path signals of the second device;

in accordance with a determination that the target time window for the signal and a further target time window for the further signal are different, , obtain a portion the signal during the target time window and a further portion of the further signal during the further target time window;

perform the frequency-domain transformation on the portion of the signal and the further portion of the further signal; and

combine the transformed portion of the signal and the transformed further portion of the further signal after delay alignment between the further signal and the signal.
The first device of claim 4, wherein the first device is further caused to:

compare a round trip delay between the first and second devices being less than a threshold delay;

in accordance with a determination that the round trip delay is less than the threshold delay, generate a further set of windows;

obtain a first portion of the signal during the set of time windows and a second portion of the signal during the further set of windows;

perform the frequency-domain transformation on the first and second portions of the signal; and

combine the transformed first and second portions of the signal.
The first device of claim 1, wherein the first device is further caused to:

configure a set of physical uplink shared channel (PUSCH) occasions for monitoring the signal, the set of PUSCH occasions being lack of gaps between each other; and

configure a gap at the end of the set of PUSCH occasions, a duration of the gap being equal to or larger than a round trip delay between the first and second devices.
The first device of claim 1, wherein the first device comprises a network device and the second device comprises a terminal device.
The first device of claim 1, wherein the frequency-domain transformation comprise a fast Fourier transform.
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 to:

receive from a first device a configuration of an uplink transmission, the configuration indicating that a length of a cyclic prefix is to be same as a length of a sequence in one symbol;

generate a signal based on the configuration; and

transmit the signal to the first device.
The second device of claim 11, wherein the second device is caused to generate the signal by:

generating the cyclic prefix by duplicating the sequence.
The second device of claim 11, wherein the second device is caused to receive the configuration of uplink transmission by:

in accordance with a determination that a random access procedure is triggered, receiving the configuration of uplink transmission.
The second device of claim 13, wherein the random access procedure comprises a two-step random access procedure.
The second device of claim 11, wherein the first device comprises a network device and the second device comprises a terminal device.
A method comprising:

transmitting, from a first device and to a second device, a configuration of an uplink transmission, the configuration indicating that a length of a cyclic prefix is to be same as a length of a sequence in one symbol;

receiving, from the second device, a signal generated based on the configuration; and

performing a frequency-domain transformation on the signal.
The method of claim 16 wherein transmitting the configuration of uplink transmission comprises:

in accordance with a determination that a random access procedure is triggered, transmitting the configuration of uplink transmission.
The method of claim 17, wherein the random access procedure comprises a two-step random access procedure.
The method of claim 16, wherein performing a frequency-domain transforming on the signal comprises:

generating a set of time windows for the frequency-domain transformation, a length of one from the set of time windows being same as the length of the cyclic prefix; and

determining at least one target time window for processing the signal based on overlapping between the set of time windows and the signal.
The method of claim 19, further comprising:

receiving a further signal from the second device, the further signal and the signal being multi-path signals of the second device;

comparing a delay spread between the signal and the further signal with the length of cyclic prefix; and

in accordance with a determination that the delay spread is less than half of the length of the cyclic prefix, generating a further set of time windows for processing the signal and the further signal.
The method of claim 19, further comprising:

receiving a further signal from the second device, the further signal and the signal being multi-path signals of the second device;

in accordance with a determination that the target time window for the signal and a further target time window for the further signal are different, obtaining a portion the signal during the target time window and a further portion of the further signal during the further target time window;

performing the frequency-domain transformation on the portion of the signal and the further portion of the further signal; and

combining the transformed portion of the signal and the transformed further portion of the further signal after delay alignment between the further signal and the signal.
The method of claim 19, further comprising:

comparing a round trip delay between the first and second devices being less than a threshold delay;

in accordance with a determination that the round trip delay is less than the threshold delay, generating a further set of windows;

obtaining a first portion of the signal during the set of time windows and the further set of windows and a second portion of the signal during the further set of time windows;

performing the frequency-domain transformation on the first and second portions of the signal; and

combining the transformed first and second portions of the signal.
The method of claim 16, further comprising:

configuring a set of physical uplink shared channel (PUSCH) occasions for monitoring the signal, the set of PUSCH occasions being lack of gaps between each other; and

configuring a gap at the end of the set of PUSCH occasions, a duration of the gap being equal to or larger than a round trip delay between the first and second devices.
The method of claim 16, wherein the first device comprises a network device and the second device comprises a terminal device.
The method of claim 16, wherein the frequency-domain transformation comprise a fast Fourier transform.
A method comprising:

receiving, at a second device and from a first device, a configuration of an uplink transmission, the configuration indicating that a length of a cyclic prefix is to be same as a length of a sequence in one symbol;

generating a signal based on the configuration; and

transmitting the signal to the first device.
The method of claim 26, wherein generating the signal comprises:

generating the cyclic prefix by duplicating the sequence.
The method of claim 26, wherein receiving the configuration of uplink transmission comprises:

in accordance with a determination that a random access procedure is triggered, receiving the configuration of uplink transmission.
The method of claim 28, wherein the random access procedure comprises a two-step random access procedure.
The method of claim 26, wherein the first device comprises a network device and the second device comprises a terminal device.
An apparatus comprising means for performing a process according to any of claims 16-30.
An apparatus comprising circuitry configured to cause the apparatus to perform a process according to any of claims 16-30.
A computer program product encoded with instructions for performing a process according to any of claims 16-30.