WO2018029493A1

WO2018029493A1 - Lte+nr dual connectivity with single/common uplink

Info

Publication number: WO2018029493A1
Application number: PCT/GB2017/052391
Authority: WO
Inventors: Tim Frost; Yannick Le Pezennec; Alexej Kulakov
Original assignee: Vodafone IP Licensing Ltd
Current assignee: Vodafone IP Licensing Ltd
Priority date: 2016-08-12
Filing date: 2017-08-14
Publication date: 2018-02-15
Anticipated expiration: 2019-02-12
Also published as: GB201613897D0

Abstract

The present invention provides a method of communicating data between a base station and a subscriber device in a telecommunications network. The telecommunications network comprises a first radio access technology, RAT, operating in a first frequency channel. The first frequency channel comprises a first application data channel part and a signalling communication channel part. The first frequency channel occupies a first range of frequencies. The telecommunications network comprises a second RAT operating in a second frequency channel. The second frequency channel comprises a second application data channel part. The second RAT is different from the first RAT. The second frequency channel occupies a second range of frequencies. The method comprises communicating a first portion of downlink application data from the base station to the subscriber device using the first application data channel part. The method further comprises communicating a second portion of the downlink application data from the base station to the subscriber device using the second application data channel part. The method further comprises communicating signalling information from the subscriber device to the base station using the signalling communication channel part. The signalling information comprises signalling information for the first application data channel part and signalling information for the second application data channel part.

Description

LTE+NR DUAL CONNECTIVITY WITH SINGLE/COMMON UPLINK

Background Within LTE there are essentially two planes of operation defined within the LTE radio interface protocol stack: 1 ) the control plane which transports Radio Resource Control signalling, and 2) the user plane that transports application data across the interface.

Within the current LTE Dual Connectivity architecture, the User Plane data, when being transferred in downlink direction, is able to be split by the Master eNode B at a Packet Data Convergence Layer between each Base Station and delivered to the User Equipment (UE) by both the Master eNode B via frequency channel 1 , and the Secondary eNode B via frequency channel 2. The transfer of Control Plane information is performed by the Master eNode B purely via frequency channel 1 directly from the Master eNode B.

In general within LTE, efficient transfer of information over the radio interface to a mobile terminal (UE) makes use of dynamic control information provided from the UE to the eNode B. This control information typically is used to support the following functions:

• HARQ (Hybrid Adaptive Repeat Request) To support this, the UE monitors whether it has successfully received one or more blocks of data from an eNode B, and provides feedback to the eNode B via control information sent on the radio interface as to whether each block has been received or not.

• Dynamic configuration of radio interfaces resources to support downlink data

transfer: To support this, the UE measures the radio channel received from the eNode B, and describes what it sees, or what it would be able to receive in terms of data formats or physical channel configurations, via control information signalled to the eNode B.

• Dynamic configuration of radio resource to support uplink data transfer: To support this function, the UE indicates to the eNode B via control information that it has data to send.

Operation of 2 uplink frequency channels by the mobile terminal and drawbacks

Within the LTE Dual Connectivity architecture, this dynamic control information is required to be transferred directly from the UE to each eNode B involved in the connection (each operating on a different frequency channel). This leads to a requirement for the UE to support simultaneous transmission of 2 uplink frequency channels. Such an approach improves system performance when the UE is connected to two different eNode Bs, but if the UE is operating both the Master and Secondary functions in the same eNode B then this it causes the following issues:

1 . The UE is limited in its transmission power, and this power needs to be shared between f1 and f2. Splitting data across two different frequencies may lead to some link inefficiencies compared to combining on a single frequency. These

inefficiencies in the uplink coverage on each carrier from this UE may in turn impact the downlink coverage (due to the uplink being used to feedback information to help decide how to serve the UE on downlink).

2. Especially when f 1 and f2 are mapped to different frequency bands, this can lead to significant complexity in the UE, as well as battery life degradation.

3. When the NR carrier is TDD, there could be issues in sending control feedback quickly due to limited uplink subframes, which would limit data rate and ability to enable low latency services in the NR cell. Being able to transmit uplink control feedback on the LTE FDD carrier would resolve this issue. For LTE Dual Connectivity, locating Master and Secondary eNode B functions being located in the same physical eNode B would never occur, as there are other mechanisms such as Carrier Aggregation which would be used here.

For LTE Dual Connectivity, locating Master and Secondary eNode B functions being located in the same physical eNode B would never occur, as there are other mechanisms such as Carrier Aggregation which would be used here.

Summary The present invention provides a method of communicating data between a base station and a subscriber device in a telecommunications network. The telecommunications network comprises a first radio access technology, RAT, operating in a first frequency channel. The first frequency channel comprises a first application data channel part and a signalling communication channel part. The first frequency channel occupies a first range of frequencies. The telecommunications network comprises a second RAT operating in a second frequency channel. The second frequency channel comprises a second application data channel part. The second RAT is different from the first RAT. The second frequency channel occupies a second range of frequencies. The method comprises communicating a first portion of downlink application data from the base station to the subscriber device using the first application data channel part. The method further comprises communicating a second portion of the downlink application data from the base station to the subscriber device using the second application data channel part. The method further comprises communicating signalling information from the subscriber device to the base station using the signalling communication channel part. The signalling information comprises signalling information for the first application data channel part and signalling information for the second application data channel part.

Advantageously, by including the signalling data for both frequency channels in only one of the channels, the subscriber device is able to dynamically make use of the additional capacity provided by combining the spectrum resources from the first and second RATs to boost the offered throughput to the subscriber device in the downlink direction. Moreover, the subscriber device is able to send fast feedback to the base station so that the base station parameters may be adjusted to improve the service quality of each of the RATs. In addition, combining the signalling into a single signalling channel part may reduce the transmit power requirements and processing requirements for the subscriber device. This is because maintaining simultaneous transmission of two uplink frequency channel parts may be costly in terms of system resources. The signalling information for the first and second application data channel parts may be jointly encoded to a first physical transmission format. The encoded signalling information may be modulated onto a first carrier waveform transmitted over the first frequency channel. The signalling information for the first and second application data channel parts may be encoded using first and second physical transmission formats respectively. The encoded signalling information for the first and second application data channel parts may each be modulated onto a first carrier waveform transmitted over the first frequency channel. The first and second physical transmission formats may be different physical transmission formats. The encoded signalling information for the first and second application data channel parts may be jointly modulated onto a single first carrier waveform transmitted over the first frequency channel or may each be modulated onto separate first carrier waveforms that are multiplexed before transmission on the first frequency channel. Signalling information for the first and second application data channel parts may be encoded using first and second physical transmission formats respectively. The encoded signalling information for the first and second application data channel parts may be modulated onto first and second carrier waveforms. Each of the first and second carrier waveforms may be transmitted over the first frequency channel. The first and second carrier waveforms may be different waveforms.

Signalling information for the first application data channel part may be transmitted on the signalling channel part during a first plurality of timeslots. Signalling information for the second data channel part may be transmitted on the signalling channel part during a second plurality of timeslots, interspersed between the first plurality of timeslots.

The signalling communication channel part may occupy a frequency range and may comprise a plurality of carrier frequencies each having a carrier frequency within the frequency range. Each of the carrier frequencies may be orthogonal to all the other carrier frequencies of the signalling communication channel part. Signalling information for the first application data channel part may be transmitted on a first carrier at a first carrier frequency of the signalling communication channel part. Signalling information for the second application data channel part may be transmitted on a second carrier at a second carrier frequency of the signalling communication channel part, different from and orthogonal to the first carrier frequency.

The signalling information for the first and/or second application data channel parts may comprise feedback information relating to whether application data packets transmitted by the base station have been successfully received by the subscriber device using the respective application data connection.

The signalling information for the first and/or second application data channel parts may comprise feedback information relating to an observed signal quality of the respective frequency channel, based on the respective portion of the downlink application data received at the subscriber device The signalling information for the first and/or second application data channel parts may comprise an indication that the subscriber device has uplink application data to transmit to the base station using the respective frequency channel.

The signalling information for the first application data channel part may comprise an indication that the subscriber device has uplink application data to transmit to the base station using the first frequency channel. The method may further comprise

communicating uplink application data from the subscriber device to the base station using the first frequency channel.

The second frequency channel may only be used for communicating downlink application data from the base station to the subscriber device. In other words, the second frequency channel is a downlink only channel used for extending capacity of the data connection between the subscriber device and the base station in the downlink direction only.

The first RAT may be 4G Long-Term Evolution, LTE. The second RAT may be 5G New Radio, NR. Alternatively, the second RAT may be 4G LTE and the first RAT may be 5G NR.

The first waveform may be an LTE Orthogonal Frequency Division Multiplexed, LTE- OFDM, waveform and the second waveform may be a New Radio, NR waveform.

Alternatively, the second waveform may be an LTE Orthogonal Frequency Division Multiplexed, LTE-OFDM, waveform and the first waveform may be a New Radio, NR waveform.

Either or both of the first and second waveforms may be a single-carrier frequency division multiple access, SC-FDMA waveform. Encoded signalling information may be modulated onto the first and/or second carrier waveform according to binary phase shift keying, BPSK, or quadrature phase shift keying, QPSK.

The method may further comprise communicating configuration information between the subscriber device and the base station. The configuration information may comprise an indication that the subscriber device is capable of transmitting signalling information for the first and second application data channel parts using the signalling communication channel part of the first RAT. The configuration information may further comprise a frequency range over which the subscriber device is capable of transmitting the signalling information using the first signalling communication channel part.

The configuration information may further comprise an indication of the first range of frequencies that the first frequency channel may occupy and/or an indication of the second range of frequencies that the second frequency channel may occupy. In other words, the frequency range over which data will be transmitted using the first/second RAT.

The configuration information may further comprise an indication identifying a portion of the first frequency channel to be occupied by the signalling communication channel part. The portion of the first frequency channel may be a time domain resource such as particular subframes, slots, or modulation symbols and/or a frequency domain resource such as resource blocks or OFDM subcarriers. The telecommunications network may further comprise a secondary base station. The second frequency channel may be a channel between the secondary base station and the subscriber device. Communicating a second portion of the downlink application data from the base station to the subscriber device using the second application data channel part may be achieved by communicating the second portion of the downlink application data from the base station to the secondary base station and communicating the second portion of the downlink application data from the secondary base station to the subscriber device using the second application data channel part.

Alternatively, a network entity in communication with the base station and the secondary base station may send the first portion of the downlink application data to the base station and the second portion of the downlink application data to the secondary base station. This network entity may receive and may be responsible

The first frequency channel may be a channel between the base station and the subscriber device. The secondary base station may be remotely located from the first base station.

The first and second frequency channels may be channels through different points in space.

Signalling information for the second application data channel part may be communicated from the base station to the secondary base station. Alternatively, a network entity in communication with the base station and the secondary base station may receive signalling information for the second application data channel part from the base station and communicate signalling information for the second application data channel part to the secondary base station. The second range of frequencies may be different from the first range of frequencies.

The present invention also provides an system or apparatus configured to perform a method as mentioned above. The system or apparatus may be a network entity. The system or apparatus may be a subscriber device (or terminal). The system or apparatus may be one or more base stations.

The present invention also provides a method of transmitting and receiving data at one or more base stations to and from a subscriber device in a telecommunications network. The telecommunications network comprises a first radio access technology, RAT, operating in a first frequency channel. The first frequency channel comprises a first application data channel part and a signalling communication channel part. The first frequency channel occupies a first range of frequencies. The telecommunications network comprises a second RAT operating in a second frequency channel. The second frequency channel comprises a second application data channel part. The second RAT is different from the first RAT. The second frequency channel occupies a second range of frequencies. The method comprises transmitting a first portion of downlink application data from the one or more base stations to the subscriber device using the first application data channel part. The method further comprises transmitting a second portion of the downlink application data from the one or more base stations to the subscriber device using the second application data channel part. The method further comprises receiving signalling information at the one or more base stations transmitted from the subscriber device using the signalling communication channel part. The signalling information comprises signalling information for the first application data channel part and signalling information for the second application data channel part.

The present invention further provides a system comprising one or more base stations configured to transmit and receive data from a subscriber device in a telecommunications network. The telecommunications network comprises a first radio access technology, RAT, operating in a first frequency channel. The first frequency channel comprises a first application data channel part and a signalling communication channel part. The first frequency channel occupies a first range of frequencies. The telecommunications network comprises a second RAT operating in a second frequency channel. The second frequency channel comprises a second application data channel part. The second RAT is different from the first RAT. The second frequency channel occupies a second range of

frequencies. The system is further configured to transmit a first portion of downlink application data to the subscriber device using the first application data channel part. The system is further configured to transmit a second portion of the downlink application data to the subscriber device using the second application data channel part. The system is further configured to receive signalling information transmitted from the subscriber device using the signalling communication channel part. The signalling information comprises signalling information for the first application data channel part and signalling information for the second application data channel part.

The present invention also provides a method of transmitting and receiving data at a subscriber device to and from one or more base stations in a telecommunications network. The telecommunications network comprises a first radio access technology, RAT, operating in a first frequency channel. The first frequency channel comprises a first application data channel part and a signalling communication channel part. The first frequency channel occupies a first range of frequencies. The telecommunications network comprises a second RAT operating in a second frequency channel. The second frequency channel comprises a second application data channel part. The second RAT is different from the first RAT. The second frequency channel occupies a second range of

frequencies. The method comprises receiving a first portion of downlink application data at the subscriber device transmitted from the one or more base stations to the subscriber device using the first application data channel part. The method further comprises receiving a second portion of the downlink application data at the subscriber device transmitted from the one or more base stations to the subscriber device using the second application data channel part. The method further comprises transmitting signalling information from the subscriber device to the one or more base stations using the signalling communication channel part. The signalling information comprises signalling information for the first application data channel part and signalling information for the second application data channel part.

The present invention further provides an apparatus (such as a subscriber device or terminal) configured to transmit and receive data from one or more base stations in a telecommunications network. The telecommunications network comprises a first radio access technology, RAT, operating in a first frequency channel. The first frequency channel comprises a first application data channel part and a signalling communication channel part. The first frequency channel occupies a first range of frequencies. The telecommunications network comprises a second RAT operating in a second frequency channel. The second frequency channel comprises a second application data channel part. The second RAT is different from the first RAT. The second frequency channel occupies a second range of frequencies. The apparatus is further configured to receive a first portion of downlink application data transmitted from the one or more base stations using the first application data channel part. The apparatus is further configured to receive a second portion of the downlink application data transmitted from the one or more base stations using the second application data channel part. The apparatus is further configured to transmit signalling information to the one or more base stations using the signalling communication channel part. The signalling information comprises signalling information for the first application data channel part and signalling information for the second application data channel part.

The present invention also provides a computer-readable storage medium containing instructions that, when executed on a processor, cause the processor to perform a method as mentioned above.

Brief Description of the Drawings

Figure 1 shows LTE+NR Dual Connectivity example architecture with LTE master. Figure 2 shows single uplink operation with dynamic control information being sent on a single frequency channel.

Figure 3 shows an example of insertion of NR information or LTE+NR information into the LTE resource grid.

Detailed Description of Preferred Embodiments

LTE+NR joint operation, and why 2 uplink frequency channels are unnecessary

Figure 1 shows how a "Dual Connectivity"-like architecture would likely apply for an LTE+NR scenario. It shows the case where the LTE protocols are used to perform the Master eNode B functions and the NR protocols are used to perform the Secondary eNode B functions. However, it is also feasible for the Master eNode B functions to be performed by NR protocols and for the Secondary eNode B functions to be performed by the LTE protocols.

Differently to LTE Dual Connectivity, for LTE+NR operation, there will be scenarios where LTE and NR radio interface transmission and reception are collocated in the same Base Station, and LTE and NR will both operate on different frequency channels (let's say f1 and f2 respectively). Simultaneous transmission by the mobile terminal on two uplink frequency channels would result in the problems highlighted above, but with no actual alternative benefits to user experience or to operation. Observation: When the UE operating LTE+NR on independent frequency channels does not require high data rates in the uplink direction, then requiring UE transmission on f1 and f2 is unnecessary.

Existing solutions to the above observation

The only alternative solution that has been proposed so far for NR operation is to have a standalone operation (where only frequency channel for NR in this case would be active and only the NR radio is active). The problem with this is that it does not allow the UE to take advantage dynamically of the additional capacity enabled by combining the NR and LTE spectrum resources to boost offered throughput to the mobile terminal in downlink direction, and it does not resolve the inability to send fast feedback if the NR cell is operating TDD (Time Division Duplex).

3GPP is developing specifications for a new radio access technology, called NR. LTE and NR radio coverage would both need to coexist in the same geographical area in a network, and in one scenario will be operated simultaneously at the same Base Station site. A required mode of operation for the NR radio is where it is deployed using a frequency channel centred on f2, and LTE operated a frequency channel centred on f1 , and whereby the frequency channel (f1 ) used by LTE is used by the mobile terminal to establish a signalling connection from IDLE, and where both the LTE channel/f1 and the NR channel/f2 are both used to transport application data from the mobile network to the UE

simultaneously (and possibly vice versa in uplink direction. This will enable the user throughputs to be maximised by aggregating the LTE and NR radio resources on f1 and f2. The starting assumption for such a deployment scenario is that the radio access network architecture used will be similar to the "Dual Connectivity" architecture that is currently specified for LTE. See 3GPP TS 36.300 (from Release12 onwards) for more details.

Solution of the present invention

In order to avoid the mobile terminal from having to transmit LTE and NR dynamic control information on 2 frequency channels simultaneously, we propose to define that the dynamic control information sent by the mobile terminal to the Base Station for LTE and NR can both be signalled on the same frequency channel. This is shown in figure 2, where the left diagram shows dynamic control information for NR is being sent with the normal LTE radio over the frequency channel f1 , and the right diagram shows dynamic control information for LTE being sent with the normal NR radio on the frequency channel f2. In both cases it is also possible to use dynamic information for both NR and LTE in a combined format.

The information that would be included within dynamic control information reported by the mobile terminal in NR includes one or more of the following:

• Layer 2 protocol feedback (similar to HARQ in LTE): Feedback to the Base Station as to whether transmitted block of data have been received or not. Channel Quality Reporting information: Description of radio channel, or what it would be able to receive in terms of data formats or physical channel

configurations, via control information signalled to the Base Station. This could include information on delay spread of the channel.

Indication to the Base Station that the mobile terminal has data to send to allow the Base Station to configure uplink radio resources for the mobile terminal.

The proposed detailed methods to enable this are defined below: Solution 1

LTE dynamic control information and NR dynamic control information are encoded onto different physical waveforms (e.g. LTE-OFDM and NR waveform). The mobile terminal is configured to transmit the waveforms for LTE and NR at different times on the same frequency channel, using Time Division Multiplexing (TDM) of the LTE and NR physical waveforms, AND/OR on adjacent frequency channels using Frequency Division

Multiplexing (FDM). In this solution, the time domain resource could refer to particular subframes, slots, or modulation symbols. In the frequency domain this may refer to a number of Hz of unused spectrum during a particular time interval.

The following signalling support would be needed between the UE and the Base Station (the remaining text in this section is also valid for solution 2):

• The UE would need to provide information to indicate that it supports the following:

o Operation of NR dynamic control transmissions multiplexed on an LTE

frequency channel

o Operation of LTE dynamic control transmissions multiplexed onto an NR frequency channel

o The frequency bands for which such uplink operation is supported by the UE

• The Base Station would also need to configure such operation in the UE. The

following information would likely need to be configured:

o The EARFCN (channel number) indicating the LTE channel where NR uplink operation is required

o The NR frequency channel number indicating the NR channel where LTE uplink operation is required The time and/or frequency resource location(s) in which the dynamic control information is to be transmitted on the required frequency channel. This could be indicated in the time domain on subframe, slot, or symbol (including multiples) level, or using an LTE uplink TTI (transmission time interval) index, or it can be indicated using a periodicity and a reference time instance. This can be indicated on frequency domain by specifying

Resource Blocks, Resource Block Groups, or Subcarriers that are to be used The signalling to configure the UE could be performed either via semi-static signalling, e.g. RRC signalling, or dynamic signalling at physical layer, or a hybrid of the two approaches. The benefit of dynamic signalling would be that it would provide more flexibility for the resource locations to be changed frequently - e.g. depending on the LTE radio load and served traffic types at any given time.

Solution 2

LTE dynamic control information and NR dynamic control information are encoded onto different physical transmission formats (e.g. LTE PUCCH, and NR uplink control channel) of the same waveform. The mobile terminal is configured to transmit the encoded block of dynamic control information for LTE and NR at different times but on the same frequency channel, using Time Division Multiplexing (TDM) of the LTE and NR transmissions, AND/OR using Frequency Division Multiplexing (FDM) within the same frequency channel, if this frequency channel consists of a subcarrier-based waveform such as OFDM. In this solution, the time domain resource could refer to particular subframes, slots, or modulation symbols. In the frequency domain this may refer to one or more resource blocks or OFDM subcarriers.

Solution 3

LTE dynamic control information and NR dynamic control information are transmitted using a common transmission format and a common waveform. In this scenario, the waveform and transmission format is represented as a number of digital bits, and the dynamic control information for LTE and NR are mapped onto these bits jointly. In this scenario the same digital bits may be used to carry dynamic control information for both LTE and NR or different bits may be used but in both cases the information is jointly encoded before being transmitted.

Such a channel would have the following properties:

• Waveform: E.g. SC-FDMA-based or some other waveform, etc.

• Coding: E.g. Turbo coding, or some other waveform, etc.

• Modulation: E.g. BPSK, QPSK etc.

• A pilot information to allow for reliable decoding of the control channel by the Radio Network

• Information coded:

o LTE HARQ ACK/NACK reporting on success of downlink data delivery, o LTE Channel Quality Information,

o LTE Precoding Matrix Information,

o Scheduling Request for resources in either or both LTE and NR radio cells, o NR ACK/NACK of data reception

o NR radio Channel Quality Info report

o NR suggested downlink transmission configuration (including precoding matrix information to allow the Base Station to optimise MIMO operation for the UE)

Not all of the information would necessarily be carried simultaneously, and different formats could be defined depending on which combination of information is to be provided. One such combination could also include "only" sending those elements relating to NR radio. Table 1 below shows an example of formats for such a channel.

Table 1 : Example formats for new uplink control channel

+ LTE Precoding

Matrix Information

+ NR channel

quality report

QPSK

The following information would be signalled between Radio Network and mobile terminal (UE):

• UE capability to support the new uplink control channel would need to be signalled from UE to Radio Network, along with any limitations on which frequency bands this channel is be operated on. This may be required especially if the new channel has a design similar to LTE and dissimilar to NR radio.

• Parameters to configure the operation of the new channel in the UE. This would include:

o The spectral frequency on which to transmit the new channel

o The resource locations in time and frequency in which the UE is required to transmit the new channel.

^■ If this is operated on the LTE frequency channel it would likely be at the edge resource blocks of the LTE carrier, and the blue blocks in figure 3 could be used to transmit such a channel. ^■ If operated on the NR frequency channel then more options are

possible, and it depends on the final NR radio physical layer design. Which combination of information is to be sent in each resource location, if all the information is not transmitted in every transmission instance. This could also require a larger set of resources (e.g. more time or frequency resources).

Realisation of these 3 solutions within the LTE and NR dual connectivity scenario The following describes how each solution can be applied to different deployment scenarios:

• Scenario 1 : LTE is operated on frequency channel f 1 , and NR is operated on

frequency channel f2. The physical transmitted signal(s) for dynamic control information transfer for NR and LTE are both carried on frequency channel f 1 , and: a) In option 1 and 3 is interleaved in a TDM manner within the channel bandwidth of the LTE transmission, AND/OR operates in an adjacent frequency to the channel bandwidth of the LTE transmission b) In option 2 and 3 is interleaved within the time and/or frequency resources of the LTE transmission

· Scenario 2: LTE is operated on frequency channel f 1 , and NR is operated on

frequency channel f2. The physical transmitted signal(s) for dynamic control information transfer for NR and LTE are both carried on frequency channel f2, and: c) In option 1 and 3 is interleaved in a TDM manner within the channel bandwidth of the NR transmission, AND/OR operates in an adjacent frequency to the channel bandwidth of the NR transmission

d) In option 2 and 3 is interleaved within the time and/or frequency resources of the NR transmission

Optionally if the LTE and NR base stations are not collocated and if there is a control interface between them, then if the LTE/NR base station receives the combined signal, then it would provide the received information to the NR/LTE base station.

In figure 3, an example embodiment of Scenario 1 b above is depicted. Scenario 2b could have a similar mapping. Benefits and drawbacks of the solutions 1 , 2, 3

The method of the present invention is carried out at a network device. For example, the method may be performed between a subscriber device and a base station. The base station may be an eNodeB. Optionally a secondary eNodeB is also used.

The subscriber device may be a user operated mobile device such as a mobile handset, smart phone personal data assistant, computer tablet and the like. Alternatively, the subscriber device may be a machine to machine, M2M device. The device may be included in the internet of things, IOT.

The present invention refers to time division multiplexing and frequency division multiplexing the signalling information for the first and second application data channels. The skilled person is familiar the terms time and frequency division multiplexing and is familiar with a number of techniques for multiplexing data signals onto carrier signals for transmission across a wireless network. For example, the skilled person would appreciate that code division multiplexing, CDM, may be used as an alternative or additional technique. The skilled person would further realise that these multiplexing techniques may be used alone or in combination with each other in a number of ways to improve the use of the resources available in the frequency channel.

It will be understood that the exemplary embodiments described herein may be

implemented to provide data-only connectivity or may be operated in combination with voice services (circuit switched services or IP voice services).

The embodiments described herein may be implemented on any device operating system. The skilled person may implement the present invention in different ways depending on the specific requirements of the subscriber device or base station. The method may be automated or semi-automated. Certain steps of the method may be performed manually with user inputs being required for some of the configuration steps, for example.

Any reference to 'an' item refers to one or more of those items. The term 'comprising' is used herein to mean including the method blocks or elements identified, but that such blocks or elements do not comprise an exclusive list and a method or apparatus may contain additional blocks or elements.

While terminals are often referred to as "mobile" in the preceding discussion the term "mobile" should not be construed to require that a terminal always be mobile, merely that it has the capability of being in communication with a wireless telecommunications network or IP network, depending on the context, which allows mobility. For instance, a PC terminal or a machine to machine (M2M) client that has never moved from any particular geographic location may in a sense be considered mobile as it could be moved to a different location while still accesses the same network. The term "mobile terminal" is used in the present discussion just to be read as including the possibility of a terminal that is "semi-permanent" or even "fixed" where the context does not contradict such an interpretation. Additionally, the "network" in the preceding discussion should be thought of as having at least a wireless element and, typically, internet protocol (IP) elements.

A step of "communicating" data can be thought of as transmitting the data or receiving the data and the step of "communicating" can be performed by either the transmitting or receiving device.

A "network entity" may be one or more base stations or may be a subscriber device (or terminal).

Those skilled in the art will realise that storage devices utilised to store program

instructions can be distributed across a network. For example, a remote computer may store an example of the process described as software. A local or terminal computer may access the remote computer and download a part or all of the software to run the program. Alternatively, the local computer may download pieces of the software as needed, or execute some software instructions at the local terminal and some at the remote computer (or computer network). Those skilled in the art will also realise that by utilising conventional techniques known to those skilled in the art that all, or a portion of the software instructions may be carried out by a dedicated circuit, such as a DSP, programmable logic array, or the like.

The steps of the methods described herein may be carried out in any suitable order, or simultaneously where appropriate. Additionally, individual blocks may be deleted from any of the methods. Aspects of any of the examples or embodiments described above may be combined with aspects of any of the other examples described to form further examples without losing the effect sought. Although the present invention has been described in connection with specific exemplary embodiments, it should be understood that various changes, substitutions, and alterations apparent to those skilled in the art can be made to the disclosed embodiments.

Claims

CLAIMS:

1 . A method of communicating data between a base station and a subscriber device in a telecommunications network, the telecommunications network comprising:

a first radio access technology, RAT, operating in a first frequency channel, comprising a first application data channel part and a signalling communication channel part, wherein the first frequency channel occupies a first range of frequencies; and

a second RAT operating in a second frequency channel comprising a second application data channel part, wherein the second RAT is different from the first RAT, and wherein the second frequency channel occupies a second range of frequencies , the method comprising:

communicating a first portion of downlink application data from the base station to the subscriber device using the first application data channel part;

communicating a second portion of the downlink application data from the base station to the subscriber device using the second application data channel part; and

communicating signalling information from the subscriber device to the base station using the signalling communication channel part of the first RAT, the signalling information comprising:

signalling information for the first application data channel part; and signalling information for the second application data channel part.

2. The method of claim 1 , wherein the signalling information for the first and second application data channel parts is jointly encoded to a first physical transmission format, which is modulated onto a first carrier waveform transmitted over the first frequency channel.

3. The method of claim 1 , wherein the signalling information for the first and second application data channel parts is encoded using first and second physical transmission formats respectively, wherein the encoded signalling information for the first and second application data channel parts are each modulated onto a first carrier waveform transmitted over the first frequency channel, wherein the first and second physical transmission formats are different physical transmission formats.

4. The method of claim 1 , wherein signalling information for the first and second application data channel parts is encoded using first and second physical transmission formats respectively, wherein the encoded signalling information for the first and second application data channel parts is modulated onto first and second carrier waveforms, each being transmitted over the first frequency channel, and wherein the first and second carrier waveforms are different waveforms.

5. The method of claim 3 or claim 4, wherein signalling information for the first application data channel part is transmitted on the signalling channel part during a first plurality of timeslots; and

signalling information for the second data channel part is transmitted on the signalling channel part during a second plurality of timeslots, interspersed between the first plurality of timeslots.

6. The method of any of claims 3 to 5, wherein the signalling communication channel part occupies a frequency range, and comprises a plurality of carrier frequencies each having a carrier frequency within the frequency range, wherein each of the carrier frequencies is orthogonal to all the other carrier frequencies of the signalling

communication channel part, and wherein

signalling information for the first application data channel part is transmitted on a first carrier at a first carrier frequency of the signalling communication channel part; and signalling information for the second application data channel part is transmitted on a second carrier at a second carrier frequency of the signalling communication channel part, different from and orthogonal to the first carrier frequency.

7. The method of any preceding claim, wherein the signalling information for the first and/or second application data channel parts comprises one or more of:

feedback information relating to whether application data packets transmitted by the base station have been successfully received by the subscriber device using the respective application data connection;

feedback information relating to an observed signal quality of the respective frequency channel, based on the respective portion of the downlink application data received at the subscriber device; and

an indication that the subscriber device has uplink application data to transmit to the base station using the respective frequency channel.

8. The method of any preceding claim, wherein the signalling information for the first application data channel part comprises an indication that the subscriber device has uplink application data to transmit to the base station using the first frequency channel, wherein the method further comprises communicating uplink application data from the subscriber device to the base station using the first frequency channel.

9. The method of any preceding claim, wherein the second frequency channel is only used for communicating downlink application data from the base station to the subscriber device.

10. The method of any preceding claim, wherein the first RAT is 4G Long-Term Evolution, LTE, and the second RAT is 5G New Radio, NR; or wherein the second RAT is 4G LTE, and the first RAT is 5G NR.

1 1 . The method of any preceding claim, wherein the first waveform is an LTE

Orthogonal Frequency Division Multiplexed, LTE-OFDM, waveform and the second waveform is a New Radio, NR waveform.

12. The method of any preceding claim, wherein encoded signalling information is modulated onto the first and/or second carrier waveform according to binary phase shift keying, BPSK, or quadrature phase shift keying, QPSK.

13. The method of any preceding claim, wherein the method further comprises communicating configuration information between the subscriber device and the base station, the configuration information comprising an indication that the subscriber device is capable of transmitting signalling information for the first and second application data channel parts using the signalling communication channel part of the first RAT.

14. The method of claim 13, wherein the configuration information further comprises one or more of:

a frequency range over which the subscriber device is capable of transmitting the signalling information using the first signalling communication channel part;

an indication of the first range of frequencies that the first frequency channel may occupy; an indication of the second range of frequencies that the second frequency channel may occupy;

an indication identifying a portion of the first frequency channel to be occupied by the signalling communication channel part.

15. The method of any preceding claim, wherein the telecommunications network further comprises a secondary base station, the second frequency channel being a channel between the secondary base station and the subscriber device, wherein communicating a second portion of the downlink application data from the base station to the subscriber device using the second application data channel part is achieved by communicating the second portion of the downlink application data from the base station to the secondary base station and communicating the second portion of the downlink application data from the secondary base station to the subscriber device using the second application data channel part.

16. The method of claim 15, wherein the secondary base station is remotely located from the first base station.

17. The method of claim 15 or claim 16, wherein signalling information for the second application data channel part is communicated from the base station to the secondary base station.

18. The method of any preceding claim, wherein the second range of frequencies is different from the first range of frequencies.

19. An apparatus configured to perform the method of any preceding claim.

20. A computer-readable storage medium containing instructions that, when executed on a processor, cause the processor to perform the method of any of claims 1 to 18.

21 . A method of transmitting and receiving data at one or more base stations in a telecommunications network, wherein data is transmitted to and received from a subscriber device in the telecommunications network, the telecommunications network comprising: a first radio access technology, RAT, operating in a first frequency channel comprising a first application data channel part and a signalling communication channel part, wherein the first frequency channel occupies a first range of frequencies; and

a second RAT operating in a second frequency channel, which comprises a second application data channel part, wherein the second RAT is different from the first RAT, wherein the second frequency channel occupies a second range of frequencies,

the method comprising:

transmitting a first portion of downlink application data from the one or more base stations to the subscriber device using the first application data channel part;

transmitting a second portion of the downlink application data from the one or more base stations to the subscriber device using the second application data channel part; and receiving signalling information at the one or more base stations transmitted from the subscriber device using the signalling communication channel part, wherein the signalling information comprises

signalling information for the first application data channel part; and

signalling information for the second application data channel part.

22. A system comprising one or more base stations configured to transmit data to and receive data from a subscriber device in a telecommunications network, the

telecommunications network comprising:

a first radio access technology, RAT, operating in a first frequency channel comprising a first application data channel part and a signalling communication channel part, wherein the first frequency channel occupies a first range of frequencies; and

a second RAT operating in a second frequency channel comprisnig a second application data channel part, wherein the second RAT is different from the first RAT, and wherein the second frequency channel occupies a second range of frequencies,

wherein the system is configured to:

transmit a first portion of downlink application data to the subscriber device using the first application data channel part;

transmit a second portion of the downlink application data to the subscriber device using the second application data channel part; and

receive signalling information transmitted from the subscriber device using the signalling communication channel part, the signalling information comprising:

signalling information for the first application data channel part; and

signalling information for the second application data channel part.

23. A method of transmitting and receiving at a subscriber device, wherein the data is transmitted to and received from one or more base stations in a telecommunications network, the telecommunications network comprising:

a second RAT operating in a second frequency channel comprising a second application data channel part, wherein the second RAT is different from the first RAT, wherein the second frequency channel occupies a second range of frequencies,

the method comprising:

receiving a first portion of downlink application data at the subscriber device transmitted from the one or more base stations to the subscriber device using the first application data channel part;

receiving a second portion of the downlink application data at the subscriber device transmitted from the one or more base stations to the subscriber device using the second application data channel part; and

transmitting signalling information from the subscriber device to the one or more base stations using the signalling communication channel part, the signalling information comprising:

signalling information for the first application data channel part; and

signalling information for the second application data channel part.

24. An apparatus configured to transmit data to and receive data from one or more base stations in a telecommunications network, wherein the telecommunications network comprises:

wherein the apparatus is configured to:

receive a first portion of downlink application data transmitted from the one or more base stations using the first application data channel part; receive a second portion of the downlink application data transmitted from the one or more base stations using the second application data channel part; and

transmit signalling information to the one or more base stations using the signalling communication channel part, wherein the signalling information comprises:

signalling information for the first application data channel part; and

signalling information for the second application data channel part.