GB2560760A - Methods and devices for controlling a radio access network - Google Patents

Abstract

A wireless communication device uses a plurality of sequences to represent control signalling bits such as receipt statuses, service requests, and acks or nacks. The sequences may be predetermined and at least semi-orthogonal both to each other and a reference symbol (RS). They may be Zadoff-Chu sequences, and one combination of bits may be represented by not transmitting anything. The sequences may be used to support different types of PUCCH signal, and these signals may be allocated to predetermined OFDM symbols. The OFDM symbols may be split into at least two positions using up-scaled sub-carrier spacing (SCS) which are then allocated to different wireless communication devices. Alternatively, sequences for multiple devices may be transmitted in the same position. The system finds particular application in self-contained, downlink-centric sub-frames with short-duration uplink control channels, and may be used in conjunction with URLLC services. Advantageously, the radio access network is 5G, New Radio (NR). In an alternative embodiment, a predetermined small payload is split across a discontinuous set of frequency resources in an uplink transmission.

Description

(54) Title of the Invention: Methods and devices for controlling a radio access network

Abstract Title: The use of sequences to represent control signalling bits in wireless communication (57) A wireless communication device uses a plurality of sequences to represent control signalling bits such as receipt statuses, service requests, and acks or nacks. The sequences may be predetermined and at least semi-orthogonal both to each other and a reference symbol (RS). They may be Zadoff-Chu sequences, and one combination of bits may be represented by not transmitting anything. The sequences may be used to support different types of PUCCH signal, and these signals may be allocated to predetermined OFDM symbols. The OFDM symbols may be split into at least two positions using up-scaled sub-carrier spacing (SCS) which are then allocated to different wireless communication devices. Alternatively, sequences for multiple devices may be transmitted in the same position. The system finds particular application in self-contained, downlink-centric sub-frames with short-duration uplink control channels, and may be used in conjunction with URLLC services. Advantageously, the radio access network is 5G, New Radio (NR). In an alternative embodiment, a predetermined small payload is split across a discontinuous set of frequency resources in an uplink transmission.

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Methods and devices for controlling a Radio Access Network

Technical Field

Embodiments of the present invention generally relate to wireless communication systems and in particular to devices and methods for enabling a wireless communication device, such as a User Equipment (UE) or mobile device to access a Radio Access Technology (RAT) or Radio Access Network (RAN).

Background

Wireless communication systems, such as the third-generation (3G) of mobile telephone standards and technology are well known. Such 3G standards and technology have been developed by the Third Generation Partnership Project (3GPP). The 3^rd generation of wireless communications has generally been developed to support macro-cell mobile phone communications. Communication systems and networks have developed towards a broadband and mobile system.

The 3rd Generation Partnership Project has developed the so-called Long Term Evolution (LTE) system, namely, an Evolved Universal Mobile Telecommunication System Territorial Radio Access Network, (E-UTRAN), for a mobile access network where one or more macro-cells are supported by a network device such as a base station known as an eNodeB or eNB (evolved NodeB). More recently, LTE is evolving further towards the so-called 5G or NR (new radio) systems where one or more cells are supported by a base station known as a gNB.

As with other technologies, the NR access technology deals with issues relating to uplink (UL) transmission processes. One problem is the short latency requirements for an uplink transmission with a small payload in a wireless communication system. There is also a need to include a sequence based scheme to support fast uplink control signalling transmission and a resource allocation method to improve link performance with limited power.

In 3GPP the following agreements regarding to design principles of Physical Uplink control channel (PUCCH) are made. There should be at least two types of transmissions which are supported for NR UL control channel. The UL control channel can be transmitted in short duration, possibly around the last transmitted UL symbol(s) of a slot, or in long duration, possibly with a number of symbols of one or more slots. It should be noted that one subframe currently has 14 symbols. Short duration PUCCH may have 1 - 2 symbols and its position may not be fixed. Long duration PUCCH has at least 4 symbols and could possibly have more than 14 symbols (bundling several subframes).

It is generally necessary to determine how to define and treat the potential gap at the end of a slot. When the UL control channel can be transmitted in long duration, in which the following considerations need to be addressed. Transmission over multiple UL symbols may be needed to improve coverage. FDM may be used with UL data channel within a slot. Consideration is also needed as to how to multiplex with a Sound reference signal (SRS). Another issue may occur with relation to the frequency resource and hopping, if hopping is used, which may not spread over the carrier bandwidth.

Accordingly two types of PUCCH are defined, one in short duration (e.g., 1-2 symbols) for services with short latency requirement and one in long duration (e.g., one or more subframe/transition time interval (TTI) for services having improved coverage requirements.

As a result short duration is proposed together with a self-contained structure and is compared with long duration; the coverage loss due to reduced energy due to reduced duration and to no frequency diversity with no frequency hopping if there is only one symbol for PUCCH are relevant. Even when there are two symbols, frequency hopping requires a RS (Reference Symbol) on both frequencies which will reduce the resources for Ack/Nack (acknowledge and not-acknowledge respectively) bits and the final link gain with frequency hopping is questionable.

A recent proposal has looked into how to support some latency sensitive services where a self-contained structure may be supported by NR. Many examples can be found. One from is illustrated below with respect to figures 1,2 and 3.

Referring to figure 1, there are different types of self-contained structure, for example downlink-centric and uplink centric. Downlink-centric enables a quick Ack/Nack feedback in the same TTI/subframe and uplink-centric enables a quick UL transmission within the same TTI/subframe as the UL grant message. Currently in LTE, all symbols in the same TTI/subframe can only be used for one direction and at least 3ms processing time is required. This means that both guard periods (GP) in Figure 1 are required.

A key motivation is to reduce the latency from both gNB and User Equipment (UE) processing. A short duration PUCCH has been proposed to be transmitted with the downlink-centric self-contained TTI/subframe.

In an alternative proposal RS based vs. Sequence based Ack/Nack has been considered. For the short duration PUCCH in downlink-centric TTI/subframe, there are two main options: One is to have one symbol for PUCCH while the other is to have two symbols optionally with up-scaled sub-carrier spacing (SCS). The symbol length in the time domain can be reduced to a half when the SCS is doubled and thus two symbols can be transmitted in the original one symbol length period. This is shown in figure 2.

Referring to figure 2, the key benefits of the two-symbol option are that the guard period is reduced (so there is less overhead); and referring to figure 3 the UEs have the same processing time. The pilot is assumed to be “non-processing dependent”, which means the UE can continue the processing of Ack/Nack during the pilot symbol. PUCCH payload (i.e., Ack/Nack in the figure 3) is processing-dependent information and can only be processed after the corresponding download (DL) receiving is finished. As shown in figure 3, Ack/Nack is actually processed within the period of the front GP and the Pilot symbol.

If the transmission in Subframe/TTI n+1 is not a retransmission of Subframe/TTI n, the DL processing GP can be zero since the transmission in Subframe/TTI n+1 is independent of the Ack/Nack and thus, Ack/Nack may be extended until the end of the current Subframe/TTI. If retransmission is expected in the Subframe/TTI n+1, the DL processing GP is necessary but the DL processing GP is reduced with the twosymbol option and the gNB may not be able to start a retransmission based on the received Ack/Nack in the immediate following subframe/slot due to the very short processing time.

Various options have been proposed. In a first option there is one symbol in the one symbol duration with the same SCS as DL data and/or UL data. In a further option there is more than one symbol in the 1 symbol duration with higher SCS than DL data and/or UL data.

The present invention is seeking to solve some of the outstanding problems in this domain.

Summary

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

According to a first aspect of the present invention there is provided a method for enabling a wireless communication device to access services provided by a Radio Access Network, the method comprising: configuring the wireless communication device to use one or more of a plurality of sequences to represent a set of control signalling bits for data carried between two or more wireless communications devices.

Preferably, the set of control signalling bits include at least one of one or more receipt statuses of data received; a service request of data to be transmitted; and a transmission of nothing.

Preferably, the receipt status is an Ack or a Nack.

Preferably, there are one or more combinations of the set of control signalling bits which is represented by transmitting at least one corresponding sequence from the plurality of sequences.

Preferably, the plurality of sequences comprises a predetermined set of sequences.

Preferably, the set of sequences are at least semi-orthogonal to each other.

Preferably, the plurality of sequences to support one or more different types of PUCCH signal.

Preferably, the PUCCH signal is allocated to a predetermined one or more OFDM symbols.

Preferably, when there are a plurality of PUCCH signals the method further comprising allocating each to a predetermined at least one of the predetermined one or more OFDM symbols.

Preferably the invention further comprising splitting the symbol into at least two positions.

Preferably, the positions are generated by IFFT with scaled subcarrier spacing.

Preferably, any one or more of the at least two positions or the combinations can be allocated to PUCCH signals from different wireless communication devices.

Preferably, the positions or their combinations can be allocated to a terminal device for PUCCH transmission.

Preferably, the OFDM symbols are selected implicitly by the terminal device according to the service type, terminal processing capability and/or load balancing information.

Preferably, the plurality of sequences are explicitly indicated by the base station.

Preferably, the invention further includes allocating the plurality of sequences as a different set of sequences to each of one or more different wireless communication devices.

Preferably, allocating the different sequences by at least one of signalling or indexing

According to a second aspect of the present invention there is provided a method, of resource allocation in an uplink transmission with a predetermined small payload and which includes a set of pre-allocated resources.

Advantageously, the uplink transmission with small payload my include PUCCH, PRACH and even PUSCH with very small high layer packet.

Advantageously, the set of pre-allocated resources are indicated to the terminal device via high layer signalling.

Advantageously, the set of resources are discontinuous in frequency domain with gaps in between.

Advantageously, the Radio Access Network is a New Radio/5G network.

According to a third aspect of the present invention there is provided a base station arranged to transmit configuration information to a wireless communication device configured with uplink control information to use one or more of a plurality of sequences to represent one or more receipt statuses for data carried between two or more wireless communications devices.

According to a fourth aspect of the present invention there is provided a wireless communication device configured with uplink control information to use one or more of a plurality of sequences to represent a set of control signalling bits for data carried between two or more wireless communications devices.

According to a fifth aspect of the present invention there is provided a non-transitory computer readable medium having computer readable instructions stored thereon for execution by a processor to perform the method according other aspects of the present invention.

Advantageously the set of OFDM symbols are selected implicitly by the terminal device according to the service type, terminal processing capability and/or load balancing information.

In an embodiment, a set of OFDM symbols are generated by IFFT of a set of subcarriers with selected SCS.

Advantageously the invention relates to a method of resource allocation of UL transmission with small payload and includes a set of pre-allocated resources.

Advantageously, the set of pre-allocated resources are indicated to the terminal device via high layer signalling.

Preferably, the set of resources are discontinuous in frequency domain with gaps in between.

Optionally, the set of resources are transmitted with power allocated according to the Water-pouring algorithm.

Preferably, a subset of the set of resources is selected for PUCCH transmission by a terminal device.

Advantageously, the water pouring algorithm or the subset selection is carried out with UL channel response considerations.

Advantageously, the UL channel response is obtained from DL receiving in TDD mode.

Advantageously, the UL channel response is indicated by the base station.

Advantageously, the set of pre-allocated resources of one terminal can overlap partially or fully with that of another.

Advantageously, the physical resource blocks are pre-allocated for the uplink control information.

Advantageously, there are multiple physical resource blocks allocated of which a subset are selected for transmission of the uplink control information with UL channel response considered;

Advantageously, the UL channel response is obtained from DL receiving in TDD mode.

Advantageously, the UL channel response is indicated by a base station.

Advantageously, there are multiple physical resource blocks allocated for transmission of uplink control information of different terminal devices which are overlapping.

Advantageously, the physical resource blocks are allocated different power depending on channel response.

The non-transitory computer readable medium may comprise at least one from a group consisting of: a hard disk, a CD-ROM, an optical storage device, a magnetic storage device, a Read Only Memory, a Programmable Read Only Memory, an Erasable Programmable Read Only Memory, EPROM, an Electrically Erasable Programmable Read Only Memory and a Flash memory.

Brief description of the drawings

Further details, aspects and embodiments of the invention will be described, by way of example only, with reference to the drawings. Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. Like reference numerals have been included in the respective drawings to ease understanding.

Figure 1 is a simplified diagram of a self-contained structure according to the prior art;

Figure 2 is a simplified diagram of an up-scaled PUCCH according to the prior art;

Figure 3 is a message sequence chart for processing time with up-scaled PUCCH according to the prior art;

Figure 4 is a sequence chart illustrating a transmission example for a sequence of operations according to an embodiment of the present invention;

Figure 5 is a sequence chart illustrating PUCCH multiplexing, according to an embodiment of the present invention;

Figure 6 is a sequence chart illustrating a second example of a sequence of operations, according to an embodiment of the present invention;

Figure 7 is a sequence chart illustrating a third example of a sequence of operations, according to an embodiment of the present invention;

Figure 8 is a sequence chart illustrating a fourth example of a sequence of operations, according to an embodiment of the present invention;

Figure 9 is a graph of an example of channel response in the frequency domain, according to an embodiment of the present invention;

Figure 10 is a block diagram of possible options for PRB allocation for PUCCH transmission, according to an embodiment of the present invention; and

Figure 11 shows two graphs giving simulation results, according to an embodiment of the present invention;

Detailed description of the preferred embodiments

Those skilled in the art will recognise and appreciate that the specifics of the examples described are merely illustrative of some embodiments and that the teachings set forth herein are applicable in a variety of alternative settings.

This invention provides a PUCCH design which can be considered as a combination of a sequence based message and an up-scaled SCS. Short-PUCCH placement in short-symbols (up-scaled SCS) allows flexible handling of ACK/NACK processing time both at a UE and a gNB and also increases the capacity of the PUCCH. Additionally, this invention also provides a new resource allocation method for uplink transmission.

This present invention can thus provide the following advantages to the network. The invention provides the flexibility to increase the processing time for the UE or for the gNB so that they are suitable for the required application and scenario. Interference to a payload associated with the PUCCH is avoided and the invention simplifies the future design of a PUCCH waveform with no need to consider the potential interference from a sequence based PUCCH process. As there is only a sequence detection, the complexity and processing time of both gNB and UE can be reduced. Improved link performance and accordingly better UL coverage can be achieved, particularly if UL and DL are operating in the same frequency band, such as for example time division duplex (TDD). Also the PUCCH multiplexing capability.

In a first instance a sequence based message with up-scaled SCS is considered. In the present invention it is expected that at least two types of PUCCH may be supported simultaneously.

A PUCCH signal is used for uplink control information (UCI) transmission. The UCI may comprise Hybrid Automatic Repeat reQuest (HARQ) ACK/NACK, Channel quality indicators (CQI), and/or scheduling request (SR) for uplink transmissions. The Ack/Nack bits are essentially a receipt confirming the receipt or non-receipt of data. In a generic sense this can be referred to as an indication of receipt status. In the present invention Ack/Nack are the relevant indicators. In some embodiments one or more of a set of control signalling bits may include the so called receipt statuses and further additional indicators such as the SR bit. In different signalling protocols different indicators of receipt may be used.

PUCCH may be used for two types of services. One type is broadband services, e.g., video call, which are latency sensitive. In this case, more than 1 Ack/Nack bits may be required per transport block (TB), e.g., 1 bit per code block (CB) (group). It should be noted there may be several CBs in each TB or spatial layer (group), and thus for this type of services, PUCCH may need to support multiple Ack/Nack bits. The other type of services is narrowband services, such as for example, online gaming and most Ultra Reliable Low Latency Communication (URLLC) services, which are also generally latency sensitive but have one CB in each TB. In this case PUCCH with single bit Ack/Nack may be sufficient.

An example with two UCI (Ack/Nack and/or SR) bits is given below, and three options for the UCI and sequence mapping are considered. Option 1 requires a total of 4 different sequences and each sequence is used to represent one combination of the UCI bits. Option 2 removes one sequence which is replaced by transmitting nothing and the gNB will assume two “0’s” if no sequence is detected. Option 3 uses a dedicated sequence for each bit, for example, sequence #1 for Bit 1 and sequence #2 for Bit 2, a sequence is transmitted only when the corresponding bit is “1” and the terminal may sometimes require to transmit sequence #1 and sequence #2 simultaneously. The benefit between Option 1 to Option 2 to Option 3 is the reduced number of sequences and the benefit between Option 3 to Option 2 to Option 1 is the reduced detection complexity. Further details are shown in table 1 below.

Table 1

Ack/Nack and/or SR	Option 1	Option 2	Option 3
Bit 1	Bit 2	Transmitted Sequence(s)
0	0	#1	Null	Null
0	1	#2	#1	#2
1	0	#3	#2	#1
1	1	#4	#3	#1 and #2

This invention is relevant to PUCCH with a small number of Ack/Nack bits. Various examples are given below.

It may be determined that sequence transmission only may be used to indicate the Ack/Nack. Thus, if a DL packet is successfully received, a pre-configured sequence is transmitted without payload otherwise nothing is sent. Similarly, at the gNB side, if a pre-configured sequence is detected, it is assumed that an Ack was received otherwise it will be interpreted as a Nack. Or alternatively, a pre-defined sequence can be transmitted when a DL packet is incorrectly received and at the gNB side, if a pre-configured sequence is detected, it is assumed that a Nack is received otherwise it will be interpreted as an Ack. Different sequences can be indicated to different preconfigured resources (e.g., by Radio Resource Control (RRC) signalling). For example, a sequence can be indexed from the resources where the DL transmission is received as illustrated in the formula below:

Sequence index = Function (position index)

The position index could be the physical resources block (PRB) number if multiple UEs are multiplexed in the FDM manner or the symbol number if multiple UEs are multiplexed in the TDM manner.

An alternative mode of operation is for the gNB to indicate the sequence index directly in an explicit signalling message to each UE so that the gNB can know from the sequence index the origin (i.e. the relevant UE) of the received Ack/Nack. An example is given in Figure 4, in which two potential resources are pre-configured to

URLLC services (two-symbol mini-slot). The term slot as used herein is intended to include any location in which the PUCCH may be transmitted.

When the session is set up, the relevant UEs are made aware that Ack of URLLC #1 needs to be indicated by transmitting Sequence #1 and Ack of URLLC #2 needs to be indicated by transmitting Sequence #2 in a predetermined slot or location in the data stream. In either case no payload needs to be attached. At the same time, the eMBB UE is caused to transmit PUCCH with RS plus payload. Sequences #1, #2 and RS are normally (at least nearly) orthogonal to each other and thus can be detected by the gNB simultaneously.

It should be noted that the invention globally allows UE1 and UE2 sequence transmission over same or different resources. In Figure 4, the example shows both UE1 and UE2 are using the same time/frequency resource and are sending PUCCH using orthogonal sequences.

The design of sequence needs to balance intra-correlation, i.e., the correlation between this sequence and its un-synchronized versions, and inter-correlation, i.e., the correlation between this sequence and other sequences. So non-orthogonal sequences could be acceptable if perfect intra-correction and inter-correlation cannot be achieved simultaneously. A Zadoff-Chu sequence or m-sequence could be used and possibly one long sequence could be generated by concatenating two shorter sequences.

Sequence #1 and #2 may need to be transmitted in the first up-scaled symbol, so the gNB can have more processing time when compared with the RS and Payload transmission. At the same time, interference is avoided to the payloads of other PUCCHs as no signal is transmitted in the same symbol with Ack/Nack payload.

In figure 4, a different SCS (DL and UL have a different symbol length approximately equal to 1/SCS) is used. However, the proposal here is independent on what SCS is used in the DL so it is also applicable if the same SCS (same symbol length) is used between UL and DL.

Without losing generality, the two symbols for short duration PUCCH can be further split into two positions, P1 and P2 as shown in Figure 5. The eNB can allocate implicitly or explicitly different positions for different UEs. For example, a low end UE, which may require more processing time, may be allocated to P2 while a high end UE, with more processing capability, may be allocated to P1. Additionally, the short duration PUCCHs of two different UEs may be TDM multiplexed on P1 and P2 so the short duration PUCCH capacity can be doubled.

The gNB has the flexibility to allocate different symbols to different UEs but it does not preclude any multiplexing combination with other dimensions. For example, multiple UEs can be further multiplexed either on P1 or P2 in either a CDM mode or an FDM mode. In some embodiments, even shorter symbol length with higher SCS to enable > 2 UEs multiplexing in the time domain, for example, to increase the number of symbols to 4 or 8 by increasing the SCS to 60 or 120 KHz. A basic SCS of 15 KHz is assumed.

Referring to figure 6, the sequence based PUCCH can be placed in the second half symbol as shown. This shows two UEs multiplexed in the CDM manner. One advantage of this design is that it provides increased processing time for the UE to process ACK/NAK. A further advantage is that no interference appears for the eMBB PUCCH RS (pilots). This second advantage gives rise to improved quality of channel estimation for eMBB users, which is important for good quality coherent detection of the payload.

In this case, it is also possible to further split one symbol with 30 KHz SCS into two symbols with 60 KHz SCS. As a result, the two UEs above can be TDM multiplexed as shown in Figure 7. Both the sequences in this design could be same, though the gNB knows the PUCCH transmission interval of UEs and would successfully associate the ACKs to the transmitting UE and thus be able to identify one sequence from the other.

In another example as shown in Figure 8, two TDM UEs with 60 KHz SCS are multiplexed with four other UEs who are TDM with 120KHz SCS. These combinations show that the processing time for the UEs can be flexibly controlled. UE33, in the example below has the largest DL processing time before sending ACK or NAK. gNB can thus allocate this placement to UEs which had their DL transmission later in the slot. This allocation of PUCCH resources to UEs could also be a function of where the UE gets it DL resources and does not necessarily need to be explicitly communicated.

The above mentioned processes provide means to increase the PUCCH capacity by allowing sequence transmission over short symbols. This is particularly suitable for UEs which are not coverage limited. For coverage limited UEs, gNB can use larger sequences (with for example 15KHz or 30KHz SCS) as appropriate. UEs without coverage problem, for example with very good signal to noise ratios (SNRs), can be allocated in parallel with very short sequences to thus increase the PUCCH capacity.

It is clear that each resource position or each multiplexed UE may require a different sequence and all sequences need to be (at least nearly) orthogonal to each other. If the number of orthogonal sequences allows, a separate sequence can also be used to indicate the Nack. The various proposals are summarized in Table 2 below.

Table 2 Ack/Nack mapping with Sequence index

Option A	URLLC #1	Ack	Sequence #1 transmitted
Nack	Sequence #1 NOT transmitted
URLLC #2	Ack	Sequence #2 transmitted
Nack	Sequence #2 NOT transmitted
Option B	URLLC #1	Ack	Sequence #1 transmitted
Nack	Sequence #3 transmitted
URLLC #2	Ack	Sequence #2 transmitted
Nack	Sequence #4 transmitted

The number of orthogonal sequences required by Option B is doubled when compared with Option A. This may also be relevant to multi-user multiple-input multiple-output (MU-MIMO), and a possible number of 16 orthogonal demodulation reference signals (DMRS) is proposed. When MU-MIMO is not used by PUCCH, the sequences of DMRS can be reused and configured to indicate Ack/Nack in accordance with the present invention.

If the number of nearly orthogonal sequences allows, this invention can be easily extended to cases with more PUCCH bits, for instance, more Ack/Nack bits and/or Scheduling Request (SR) bits. For example, when one Ack/Nack bit and one SR bit is need to be sent in the uplink, a group of 4 different sequences can be allocated to the UE explicitly (by signalling) or implicitly (by indexing), and as a result each combination of the two bits can be bundled with one sequence.

More specifically, the sequences used in the present invention can be generated by concatenating multiple short sequences, for example, S1 and S2 are two short sequences, [S1 S2] and [S2 S1 ] are two different sequences (length doubled) which can be used as two separate sequences in the present invention.

The above described process can further be used as a method of resource allocation for PUCCH or PRACH or PUSCH with TDD.

Short duration PUCCH has a coverage problems. To improve the coverage, several aspects need to be considered together. These are highlighted below, by way of example. In the case of peak to average power ratio I cubic metric (PAPR/CM), the

UE must essentially work with a full power output. Discrete Fourier TransformSpread- Orthogonal Frequency Division Multiplexing (DFT-s-OFDM) can be used to reduce the PAPR/CM value. Also, from the point of view of frequency diversity it is expected to schedule discontinuous physical resource blocks (PRBs) to a UE but it will increase the PAPR/CM value when DFT-s-OFDM is used. Further from the point of view of channel estimation it is expected to schedule as little PRB as possible so that each PRB can have more power and accordingly better SNR.

There is a preference for PRBs having a short duration PRB. For a short PUCCH format the PUCCH sub-band may be defined by multiple PRBs and its frequency band should not be greater than the maximum UE BW. If the UE is in TDD mode, channel response can be known by the UE from the DL receiving.

As shown in figure 9 the channel response in the frequency domain of a 20MHz bandwidth could be very different and varies subframe/TTI by subframe/TTI. First, the gNB allocates a set of discontinuous PRBs to the UE for PUCCH transmission, and the gNB needs to make sure all allocated PRBs are within the bandwidth supported by the UE. There is no need to have identical intervals between adjacent PRBs but it is preferable to have all PRBs evenly distributed in the whole transmission band. It is also possible for the gNB to re-allocate the PRBs on certain specific positions if UL channel response is known by the gNB. This information may have been derived from SRS procedures for example. The SRS are transmitted by the UEs for the gNB to estimate the UL channel response and a wideband channel response estimation can be obtained from SRS. The UE carries out the channel estimation based on the DL receiving and since the same frequency is used in both DL and UL with TDD mode, the same channel response in the UL can be assumed by the UE. The UE can select a small subset of all allocated PRBs, e.g., just one, to transmit the PUCCH. If it is power limited, fewer PRB can make sure each PRB can have a better signal to Interference plus Noise Ratio (SINR) so that a better channel estimation can be achieved at the gNB. When multiple UEs are multiplexed on the same radio resources with for example semi- orthogonal signals, the gNB needs to implement multi-UE detection and in this case, narrow bandwidth for all UEs can help to mitigate the impacts of channel response distortion which will corrupt the orthogonality amongst the UEs. From this point of view, the number of PRBs for PUCCH should be as small as possible.

Referring to figure 10, an evaluation is provided below with illustrated five options: Options 1,2 and 3 show that all the pre-allocated PRBs are used; and Options 4 and 5 both have multiple PRBs allocated but only one is selected for PUCCH transmission. For each allocated PRB, there is only one symbol in the time domain.

Other simulation assumptions can be found in table 3 below.

Table 3: Simulation attributes and values or assumptions.

Attributes	Values or assumptions
Message	Sequence based
Channel Model	TDL-C-1000ns
Power distribution	Limited and equal distribution
Bandwidth	20 MHz
Sequence length	12 but concatenated to longer one when more than 1 PRB is used

Coverage performance can be compared with the following link simulation results. Non-coherent detection is used and a threshold is selected according to the target false alarm probabilities, i.e., 1% and 0.1%. For a coverage limited scenario, full power is used and the same applies for all options, so when the PUCCH is transmitted with more PRBs, the power of each PRB is reduced accordingly.

For Options 2 and 3, the link performance is shifted by 3dB/6dB in relation to the power reduction on each PRB. For Options 4 and 5, when one PRB is selected, all other PRBs are not used. The PRB selection is based on best channel response.

As can be seen from the above simulation results in figure 9, for a missed detection probability of 1%, there is 3 - 4 dB gain depending on what the false alarm is. To improve the spectrum efficiency, it is possible to allocate multiple UEs on the same set of PRBs in a manner that is partially or fully overlapping. In this way the interference between the PUCCHs’ of different UEs can be randomized. This is based on the selection of PRBs being independent for different UEs so collision probability can be reduced; and when a collision happens, different UEs can use nearly orthogonal sequences or CDM-type modulation and coding schemes to further reduce the interference.

In an alternative embodiment, the UE can select all allocated PRBs for the PUCCH transmission but allocate different power to each PRB according to its channel response. In other word, more power is allocated to a PRB with stronger channel response and less power to a PRB with more channel fading. One algorithm for the power allocation could be for example, the Water-pouring algorithm (https://en.wikipedia.org/wiki/Water-pouring_algorithm).

The above described resource allocation method and corresponding process at the UE side can be used by all PUCCH designs, including but not limited to long duration PUCCH, short duration PUCCH, RS based message and sequence based message, and all PRACH/PUSCH designs.

The resource allocation method can be further extended to other channels with very small payload size, power limited transmission and short latency requirement. For example, PUSCH packets for gaming services for power limited UEs can be allocated with several discontinuous PRBs and the UE can select the best PRB to be used for PUSCH transmission according to the DL receiving on the same frequency. Since only channel response is needed from the DL, there is no need for the gNB to schedule anything in DL to this UE and the UE can carry out the DL channel estimation with, for example, common RS symbols.

The signal processing functionality of the embodiments of the invention especially the gNB and the UE may be achieved using computing systems or architectures known to those who are skilled in the relevant art. Computing systems such as, a desktop, laptop or notebook computer, hand-held computing device (PDA, cell phone, palmtop, etc.), mainframe, server, client, or any other type of special or general purpose computing device as may be desirable or appropriate for a given application or environment can be used. The computing system can include one or more processors which can be implemented using a general or special-purpose processing engine such as, for example, a microprocessor, microcontroller or other control module.

The computing system can also include a main memory, such as random access memory (RAM) or other dynamic memory, for storing information and instructions to be executed by a processor. Such a main memory also may be used for storing temporary variables or other intermediate information during execution of instructions to be executed by the processor. The computing system may likewise include a read only memory (ROM) or other static storage device for storing static information and instructions for a processor.

The computing system may also include an information storage system which may include, for example, a media drive and a removable storage interface. The media drive may include a drive or other mechanism to support fixed or removable storage 16 media, such as a hard disk drive, a floppy disk drive, a magnetic tape drive, an optical disk drive, a compact disc (CD) or digital video drive (DVD) read or write drive (R or RW), or other removable or fixed media drive. Storage media may include, for example, a hard disk, floppy disk, magnetic tape, optical disk, CD or DVD, or other fixed or removable medium that is read by and written to by media drive. The storage media may include a computer-readable storage medium having particular computer software or data stored therein.

In alternative embodiments, an information storage system may include other similar components for allowing computer programs or other instructions or data to be loaded into the computing system. Such components may include, for example, a removable storage unit and an interface , such as a program cartridge and cartridge interface, a removable memory (for example, a flash memory or other removable memory module) and memory slot, and other removable storage units and interfaces that allow software and data to be transferred from the removable storage unit to computing system.

The computing system can also include a communications interface. Such a communications interface can be used to allow software and data to be transferred between a computing system and external devices. Examples of communications interfaces can include a modem, a network interface (such as an Ethernet or other NIC card), a communications port (such as for example, a universal serial bus (USB) port), a PCMCIA slot and card, etc. Software and data transferred via a communications interface are in the form of signals which can be electronic, electromagnetic, and optical or other signals capable of being received by a communications interface medium.

In this document, the terms ‘computer program product’, ‘computer-readable medium’ and the like may be used generally to refer to tangible media such as, for example, a memory, storage device, or storage unit. These and other forms of computer-readable media may store one or more instructions for use by the processor comprising the computer system to cause the processor to perform specified operations. Such instructions, generally referred to as ‘computer program code’ (which may be grouped in the form of computer programs or other groupings), when executed, enable the computing system to perform functions of embodiments of the present invention. Note that the code may directly cause a processor to perform specified operations, be compiled to do so, and/or be combined with other software, hardware, and/or firmware elements (e.g., libraries for performing standard functions) to do so.

The non-transitory computer readable medium may comprise at least one from a group consisting of: a hard disk, a CD-ROM, an optical storage device, a magnetic storage device, a Read Only Memory, a Programmable Read Only Memory, an Erasable Programmable Read Only Memory, EPROM, an Electrically Erasable Programmable Read Only Memory and a Flash memory

In an embodiment where the elements are implemented using software, the software may be stored in a computer-readable medium and loaded into computing system using, for example, removable storage drive. A control module (in this example, software instructions or executable computer program code), when executed by the processor in the computer system, causes a processor to perform the functions of the invention as described herein.

Furthermore, the inventive concept can be applied to any circuit for performing signal processing functionality within a network element. It is further envisaged that, for example, a semiconductor manufacturer may employ the inventive concept in a design of a stand-alone device, such as a microcontroller of a digital signal processor (DSP), or application-specific integrated circuit (ASIC) and/or any other sub-system element.

It will be appreciated that, for clarity purposes, the above description has described embodiments of the invention with reference to a single processing logic. However, the inventive concept may equally be implemented by way of a plurality of different functional units and processors to provide the signal processing functionality. Thus, references to specific functional units are only to be seen as references to suitable means for providing the described functionality, rather than indicative of a strict logical or physical structure or organisation.

Aspects of the invention may be implemented in any suitable form including hardware, software, firmware or any combination of these. The invention may optionally be implemented, at least partly, as computer software running on one or more data processors and/or digital signal processors or configurable module components such as FPGA devices. Thus, the elements and components of an embodiment of the invention may be physically, functionally and logically implemented in any suitable way. Indeed, the functionality may be implemented in a single unit, in a plurality of units or as part of other functional units.

Although the present invention has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the scope of the present invention is limited only by the accompanying claims. Additionally, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognize that various features of the described embodiments may be combined in accordance with the invention. In the claims, the term ‘comprising’ does not exclude the presence of other elements or steps.

Furthermore, although individually listed, a plurality of means, elements or method steps may be implemented by, for example, a single unit or processor. Additionally, although individual features may be included in different claims, these may possibly be advantageously combined, and the inclusion in different claims does not imply that a combination of features is not feasible and/or advantageous. Also, the inclusion of a feature in one category of claims does not imply a limitation to this category, but rather indicates that the feature is equally applicable to other claim categories, as appropriate.

Furthermore, the order of features in the claims does not imply any specific order in which the features must be performed and in particular the order of individual steps in a method claim does not imply that the steps must be performed in this order. Rather, the steps may be performed in any suitable order. In addition, singular references do not exclude a plurality. Thus, references to ‘a’, ‘an’, ‘first’, ‘second’, etc. do not preclude a plurality.

Although the present invention has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Rather, the scope of the present invention is limited only by the accompanying claims. Additionally, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognise that various features of the described embodiments may be combined in accordance with the invention. In the claims, the term ‘comprising’ or “including” does not exclude the presence of other elements.

Claims (24)

Claims

1. A method for enabling a wireless communication device to access services provided by a Radio Access Network, the method comprising: configuring the wireless communication device to use one or more of a plurality of sequences to represent a set of control signalling bits for data carried between two or more wireless communications devices.

2. The method of claim 1, wherein the set of control signalling bits include at least one of one or more of: receipt statuses of data received; a service request of data to be transmitted; an Ack and a Nack.

3. The method of claim 1 or claim 2, wherein there are one or more combinations of the set of control signalling bits which is represented by transmitting at least one corresponding sequence from the plurality of sequences.

4. The method of claim 3, wherein the at least one combination of the set of control signalling bits is represented by not transmitting anything.

5. The method of any one of claims 1 to 4, wherein the plurality of sequences comprises a predetermined set of sequences, wherein the set of sequences are at least semi-orthogonal to each other.

6. The method of any one of claims 1 to 5, including using the plurality of sequences to support one or more different types of PUCCH signal.

7. The method of claim 6, wherein the PUCCH signal is allocated to a predetermined one or more OFDM symbols.

8. The method of claim 7, wherein when there are a plurality of PUCCH signals the method further comprising allocating each to a predetermined at least one of the predetermined one or more OFDM symbols.

9. The method of claim 7 or claim 8, further comprising splitting the symbol into at least two positions.

10. The method of claim 9, wherein the positions are generated by IFFT with scaled subcarrier spacing.

11. The method of claim 9 or 10, wherein any one or more of the at least two positions or the combinations can be allocated to PUCCH signals from different wireless communication devices.

12. The method of any one of claim 9 to 11, wherein the positions or their combinations can be allocated to a terminal device for PUCCH transmission.

13. A method, of resource allocation in an uplink transmission with a predetermined small payload and which includes a set of pre-allocated resources.

14. The method of claim 13, wherein the set of pre-allocated resources are indicated to the terminal device via high layer signalling.

15. The method of claim 13 or claim 14, wherein the set of resources are discontinuous in frequency domain with gaps in between.

16. The method of claim 13, wherein there are multiple physical resource blocks allocated of which a subset are selected for transmission of the uplink control information with UL channel response considered.

17. The method of claim 16, wherein the UL channel response is obtained from DL receiving in TDD mode.

18. The method of claim 16, wherein the UL channel response is indicated by a base station.

19. The method of claim 13, wherein there are multiple physical resource blocks allocated for transmission of uplink control information of different terminal devices which are overlapping.

20. The method of claim 13, wherein the physical resource blocks are allocated different power depending on channel response.

21. The method of any preceding claim wherein the Radio Access Network is a New Radio/5G network.

22. A base station arranged to transmit configuration information to a wireless communication device configured with uplink control information to use one or more of a plurality of sequences to represent one or more receipt statuses for data carried between two or more wireless communications devices.

23. A wireless communication device configured with uplink control information to use one or more of a plurality of sequences to represent a set of control signalling bits for data carried between two or more wireless communications devices.

24. A non-transitory computer readable medium having computer readable instructions stored thereon for execution by a processor to perform the method according to any of claims 1 -21.

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Application No: GB1704712.7 Examiner: Dr Stephen Bevan