WO2019034524A1

WO2019034524A1 - Methods for frequency hopping, electronic transceiver device, network node and computer programs

Info

Publication number: WO2019034524A1
Application number: PCT/EP2018/071625
Authority: WO
Inventors: Oskar Drugge; Yusheng Liu; David Sugirtharaj; Emma Wittenmark
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2017-08-14
Filing date: 2018-08-09
Publication date: 2019-02-21

Abstract

A method is performed by an electronic transceiver device. The electronic transceiver device is arranged to operate in a cellular communication system which enables operation in unlicensed bands and has a frame structure, for communication between the electronic transceiver device and a network node of the cellular communication system, where a first part of a frame is reserved for downlink communication and a second part of the frame is available both for downlink and uplink communication. The method comprises performing frequency hopping reception or transmission according to an initial hopping sequence which the electronic transceiver device uses until semi-static signalling assigns a specific primary hopping sequence, and, after receiving indication of the primary hopping sequence, performing frequency hopping reception or transmission according to a second pattern for the second part of the frame, wherein the second pattern is a frequency hopping sequence. A corresponding method for a network node is also disclosed, as well as computer programs, wireless transceiver device and network node.

Description

METHODS FOR FREQUENCY HOPPING, ELECTRONIC TRANSCEIVER DEVICE, NETWORK NODE AND COMPUTER PROGRAMS

Technical field

The present disclosure generally relates to an electronic transceiver device and a network node arranged to operate in a cellular communication system enabling operation in unlicensed bands and having a frame structure for communication between the electronic transceiver device and the network node where a first part of a frame is reserved for downlink communication and a second part of the frame is available both for downlink and uplink communication. In particular, the present disclosure relates to methods and computer programs for the electronic transceiver device and the network node for providing proper frequency hopping.

Background

The 3GPP work on "Licensed-Assisted Access" (LAA) intends to allow LTE equipment to also operate in the unlicensed radio spectrum. Candidate bands for LTE operation in the unlicensed spectrum include 5 GHz, 3.5 GHz, etc. The unlicensed spectrum is used as a complement to the licensed spectrum or allows completely standalone operation.

For the case of unlicensed spectrum used as a complement to the licensed spectrum, devices connect in the licensed spectrum (primary cell or PCell) and use carrier aggregation to benefit from additional transmission capacity in the unlicensed spectrum (secondary cell or SCell). The carrier aggregation (CA) framework allows to aggregate two or more carriers with the condition that at least one carrier (or frequency channel) is in the licensed spectrum and at least one carrier is in the unlicensed spectrum. In the standalone (or completely unlicensed spectrum) mode of operation, one or more carriers are selected solely in the unlicensed spectrum.

Regulatory requirements, however, may not permit transmissions in the unlicensed spectrum without prior channel sensing, transmission power limitations or imposed maximum channel occupancy time. Since the unlicensed spectrum must be shared with other radios of similar or dissimilar wireless technologies, a so-called listen- before-talk (LBT) method needs to be applied. LBT involves sensing the medium for a pre-defined minimum amount of time and backing off if the channel is busy.

Today, the unlicensed 5 GHz spectrum is mainly used by equipment implementing the IEEE 802.11 Wireless Local Area Network (WLAN) standard. This standard is known under its marketing brand "Wi-Fi" and allows completely standalone operation in the unlicensed spectrum. Unlike the case in LTE, Wi-Fi terminals can asynchronously access the medium and thus show better UL performance characteristics especially in congested network conditions.

Internet of Things, IoT, can be considered a fast evolving market within the telecommunications realm. Current 3 GPP based standards offer three different variants supporting IoT services, eMTC, NB-IoT and EC-GSM. eMTC and NB-IoT have been designed using LTE as a baseline, with the main difference between the two being the minimum occupied bandwidth. eMTC and NB-IoT use 1.4 MHz and 180 kHz minimum bandwidth respectively.

Both NB-IoT as well as eMTC have been designed with an operator deployment of macro cells in mind. Certain use cases where outdoor macro eNodeBs would communicate with IoT devices deep inside buildings are targeted, which require standardized coverage enhancement mechanisms.

3 GPP LTE Rel-12 defined a UE power saving mode allowing long battery lifetime and a new UE category allowing reduced modem complexity. 3GPP Rel-13, further introduced the eMTC feature, with a new category, Cat-Mi that further reduces UE cost while supporting coverage enhancement. The key element to enable cost reduction for Cat-Mi UE is to introduce a reduced UE bandwidth of 1.4 MHz in downlink and uplink within any system bandwidth, e.g. as demonstrated in 3GPP TR 36.888.

In LTE, the system bandwidth can be up to 20 MHz and this total bandwidth is divided into physical resource blocks (PRBs) a 180 kHz. Cat-Mi UEs with reduced UE bandwidth of 1.4 MHz only receives a part of the total system bandwidth at a time - a part corresponding to up to 6 PRBs. Here we refer to a group of 6 PRBs as a 'PRB group'.

To achieve the coverage targeted in LTE Rel-13 for low-complexity UEs and other UEs operating delay tolerant MTC applications [TR 36.888], time repetition techniques are used to allow energy accumulation of the received signals at the UE side. For physical data channels (PDSCH, PUSCH), subframe bundling (a.k.a. TTI bundling) can be used. When subframe bundling is applied, each HARQ (re)transmission consists of a bundle of multiple subframes instead of just a single subframe. Repetition over multiple subframes are also applied to physical control channels.

Energy accumulation of the received signals involve several aspects. One of the main aspects involves accumulating energy for reference signals, e.g. by applying time-filters, to increase the quality of channel estimates used in the demodulation process. A second main aspect involves accumulation of demodulated soft-bits across repeated transmissions.

Unlicensed bands offer the possibility for deployment of radio networks by non-traditional operators that do not have access to licensed spectrum, such as e.g. building owners, industrial sites and municipalities who want to offer a service within the operation they control. Recently, the LTE standard has been evolved to operate in unlicensed bands for the sake of providing mobile broadband using unlicensed spectrum. The 3GPP based feature of License Assisted Access (LAA) was introduced in Rel. 13, supporting carrier aggregation between a primary carrier in licensed bands, and one or several secondary carriers in unlicensed bands. Further evolution of the LAA feature, which only supports DL traffic, was specified within the Rel. 14 feature of enhanced License Assisted Access (eLAA), which added the possibility to also schedule uplink traffic on the secondary carriers. In parallel to the work within 3GPP Rel. 14, work within the MulteFire Alliance (MFA) aimed to standardize a system that would allow the use of standalone primary carriers within unlicensed spectrum. The resulting MulteFire 1.0 standard supports both UL and DL traffic.

Discussions are currently ongoing both within 3 GPP as well as within MFA, regarding the potential to evolve existing unlicensed standards to also support IoT use- cases within unlicensed bands. Among discussions within the MFA, it is explicitly mentioned the opportunity for developing new standards that would have either of NB- IoT or eMTC as baseline. One issue to consider for such a design are the regulatory requirements, which differ depending on frequency band and region.

It is therefore a desire to alleviate at least some issues for some frequency bands and regions.

Summary

According to a first aspect, there is provided a method performed by an electronic transceiver device. The electronic transceiver device is arranged to operate in a cellular communication system which enables operation in unlicensed bands and has a frame structure, for communication between the electronic transceiver device and a network node of the cellular communication system, where a first part of a frame is reserved for downlink communication and a second part of the frame is available both for downlink and uplink communication. The method comprises performing frequency hopping reception or transmission according to an initial hopping sequence which the electronic transceiver device uses until semi-static signalling assigns a specific primary hopping sequence, and, after receiving indication of the primary hopping sequence, performing frequency hopping reception or transmission according to a second pattern for the second part of the frame, wherein the second pattern is a frequency hopping sequence.

The initial hopping sequence may be pre-configured. The pre-configured initial hopping sequence may be determined from a mapping from any of synchronisation signals, cell identity, system information, and subscriber identity, or any combination thereof.

The method may comprise performing frequency hopping reception according to a first pattern for the first part of the frame wherein scheduling information is received, wherein the second pattern is derived from the scheduling information and the first pattern is a frequency hopping sequence. The first pattern may be pre-configured. The pre-configured first pattern may be determined from a mapping from any of synchronisation signals, cell identity, system information, and subscriber identity, Radio Resource Control signalling, Msg2 or Msg4 signalling, or any combination thereof. The pre-configured first pattern may be a default initial frequency hopping sequence.

According to a second aspect, there is provided a computer program comprising instructions which, when executed on a processor of an electronic transceiver device, causes the electronic transceiver device to perform the method according to the first aspect.

According to a third aspect, there is provided a method performed by a network node arranged to operate in a cellular communication system enabling operation in unlicensed bands and having a frame structure for communication between an electronic transceiver device and the network node of the cellular communication system where a first part of a frame is reserved for downlink communication and a second part of the frame is available both for downlink and uplink communication. The method comprises performing frequency hopping reception or transmission between the network node and the electronic transceiver device according to an initial hopping sequence until semi- static signalling assigns the electronic transceiver device a specific primary hopping sequence, and, after assigning the primary hopping sequence, performing frequency hopping transmission according to a second pattern for reception or transmission between the network node and the first electronic device during the second part of the frame. A second pattern for frequency hopping for the first electronic transceiver device is used for the second part of the frame. The second pattern is a frequency hopping sequence. The initial hopping sequence may be pre-configured. The pre-configured initial hopping sequence may be determined from a mapping from any of synchronisation signals, cell identity, system information, and subscriber identity, or any combination thereof.

The method may comprise performing frequency hopping transmission according to a first pattern for the first part of the frame wherein scheduling information is transmitted, wherein the second pattern is derivable from the scheduling information and the first pattern is a frequency hopping sequence. The first pattern may be pre- configured. The pre-configured first pattern may be determined from a mapping from any of synchronisation signals, cell identity, system information, and subscriber identity, Radio Resource Control signalling, Msg2 or Msg4 signalling, or any combination thereof. The pre-configured first pattern may be a default initial frequency hopping sequence.

The first pattern may be selected among a set of frequency hopping sequences comprising at least two sequences arranged to not mutually overlap in time and frequency. The set of sequences may be arranged such that probability of occupying a frequency is equal on average in each frequency hopping cycle.

According to a fourth aspect, there is provided a computer program comprising instructions which, when executed on a processor of a network node, causes the network node to perform the method according to the third aspect.

According to a fifth aspect, there is provided an electronic transceiver device arranged to operate in a cellular communication system which enables operation in unlicensed bands and has a frame structure, for communication between the electronic transceiver device and a network node of the cellular communication system, where a first part of a frame is reserved for downlink communication and a second part of the frame is available both for downlink and uplink communication. The electronic transceiver device is arranged to perform the method of the first aspect.

According to a sixth aspect, there is provided a network node arranged to operate in a cellular communication system which enables operation in unlicensed bands and has a frame structure, for communication between an electronic transceiver device and the network node of the cellular communication system, where a first part of a frame is reserved for downlink communication and a second part of the frame is available both for downlink and uplink communication. The network node is arranged to perform the method of the third aspect. Brief description of the drawings

The above, as well as additional objects, features and advantages of the present disclosure, will be better understood through the following illustrative and non-limiting detailed description of preferred embodiments of the present disclosure, with reference to the appended drawings.

Fig. 1 schematically illustrates an example for how eMTC-U make use of asymmetric eNB and UE bandwidth.

Fig. 2 illustrates UE vs. eNB bandwidth and definition of narrow bands.

Fig. 3 illustrates a frame structure.

Fig. 4 illustrates an example of frequency hopping sequences.

Fig. 5 illustrates a flow chart illustrating a method for a UE during initial acquisition according to an embodiment.

Fig. 6 illustrates a flow chart illustrating a method for a UE during random access according to an embodiment.

Fig. 7 illustrates a flow chart illustrating a method for a UE during connected mode according to an embodiment.

Fig. 8 illustrates a flow chart illustrating a method for an eNB during random access according to an embodiment.

Fig. 9 illustrates a flow chart illustrating a method for an eNB during paging according to an embodiment.

Fig. 10 illustrates a flow chart illustrating a method for an eNB during connected mode according to an embodiment.

Fig. 11 illustrates a flow chart illustrating a method for an electronic transceiver device according to an embodiment.

Fig. 12 illustrates a flow chart illustrating a method for a network node according to an embodiment.

Fig. 13 is a block diagram schematically illustrating an electronic transceiver device according to an embodiment.

Fig. 14 is a block diagram schematically illustrating a network node according to an embodiment.

Fig. 15 schematically illustrates a computer-readable medium and a processing device. Detailed description

One specific frequency band that may be eligible for IoT operation would be the band in the vicinity of 2.4 GHz. Requirements for the European region are specified within the ETSI harmonised standard for equipment using wide band modulation, ETSI EN 300 328. Some key requirements from ETSI EN 300 328 are discussed in the next section.

ETSI EN 300 328 provisions several adaptivity requirements for different operation modes. From the top-level equipment can be classified either as frequency hopping or non-frequency hopping, as well as adaptive or non-adaptive. Adaptive equipment is mandated to sense whether the channel is occupied in order to better coexist with other users of the channel. The improved coexistence may come from e.g. LBT, or detect and avoid (DAA) mechanisms. Non-frequency hopping equipment are subject to requirements on maximum power spectral density (PSD) of 10 dBm/MHz, which limits the maximum output power for systems using narrower bandwidths.

ETSI EN 300 328 requirements for non-adaptive frequency hopping include the following key parts:

• A maximum on-time of 5 ms, which is required to be followed by a transmission gap.

• A minimum duration of the transmission gap of 5 ms.

· A maximum accumulated transmit time of 15 ms, which is the maximum total transmission time a node may be allowed to use before moving to the next frequency hop.

ETSI EN 300 328 requirements for adaptive frequency hopping include the following key parts:

· Each transmission is preceded by an LBT.

• The maximum channel occupancy time is 60 ms, after which a new LBT needs to be performed in case the equipment prefers to continue dwelling on the same frequency.

• The maximum dwell time is 400 ms.

ETSI EN 300 328 also state requirements for any type of frequency hopping equipment on Frequency occupation according to:

Option 1 : Each hopping frequency of the hopping sequence shall be occupied at least once within a period not exceeding four times the product of the dwell time and the number of hopping frequencies in use. Option 2: The occupation probability for each frequency shall be between ((1 / U) x 25 %) and 77 % where U is the number of hopping frequencies in use.

Discussions are currently ongoing within the MulteFire Alliance Forum, to create an IoT standard, aimed for the unlicensed 2.4 GHz band, which builds on the eMTC standard as defined for use in licensed spectrum. The working name for the new standard is eMTC-U.

The latest discussions in the MulteFire Alliance Forum have among other things, converged on the following agreements for eMTC-U, mf2017.163.05:

· eNB equipment qualifies as using adaptive frequency hopping based on

LBT according to ETSI regulations, baseline assumption for bandwidth is 1.4 MHz, although wider bandwidths are for further study.

User equipment qualifies as using non-adaptive frequency hopping according to ETSI regulations, using a maximum bandwidth of 1.4 MHz

· Support a "fixed dwell time" of 80 ms with flexible DL/UL switching point.

As can be seen, one point for further study is whether the bandwidth for the eNB can be different than the bandwidth for the UE. Such an asymmetry between the UE and eNB bandwidths is for example how 5 MHz DL bandwidth can be used to fit four channels, each 6 PRB wide.

Fig. 1 illustrates an example where the eNB uses 5 MHz bandwidth and can thus receive uplink transmissions from four UEs within the bandwidth. Due to the choice to qualify UE as non-adaptive frequency hopping equipment, the UE can only transmit an accumulated time of 15 ms on each frequency before it needs to perform the next hop. Considering the example shown in Fig. 1, several open issues arise:

1) It is understood that there is a dynamic scheduling of the uplink transmissions. The scheduling of uplink transmission is presumably received during the downlink portion of the dwell, i.e. in the beginning of each eNB dwell with 5 MHz bandwidth. However, for such a concept to work, each UE needs be aware of which 1.4 MHz part of the 5 MHz DL signal it should monitor at the beginning of the eNB frame.

2) According to ETSI EN 200 328, dwell time is defined as time between frequency changes for Frequency Hopping equipment, with a note that the dwell time might comprise transmit, receive and idle phases of the equipment. In the proposal outlined, the dwell time on the frequency that is used for the initial DL transmission of a frame is much longer than the dwell times on the subsequent UL transmission. Compliance with the frequency occupation requirement may thus not be guaranteed without further consideration of the concept for UE frequency hopping.

A method is introduced wherein the UE frequency hopping sequence is defined such that

1) A primary hopping sequence defines the frequencies for the first part of each frame, defined;

a. based on a function of PCI,

b. based on system information, such as MIB or SIB,

c. based on subscriber identity, such as IMSI or assigned R TI,

d. based on Pv C signalling,

e. based on Msg2 or Msg4 signalling,

f. or any combination of the above,

wherein the primary hopping sequence is designed so that each frequency comprised in the primary hopping sequence is occurring with equal probability

2) The frequencies to dwell on during subsequent dwells within the same frame after the first part of a frame, are scheduled based on downlink control information (DCI), or other signalling mechanisms, received during the first dwell of a frame.

The basic assumption of the system which the approach is applicable for is a system which uses frequency hopping on the eNB side as well as the UE side. It is further assumed that the BW used by the eNB is larger than the BW used by the UE. The eNB frequency hopping is thus performed using a larger and different hop separation than the UE frequency hopping. If the different UEs occupy different non- overlapping parts of the eNB transmission BW, or different narrow bands, the eNB may be able to schedule multiple UEs, allocating each UE their maximum bandwidth as shown in Fig. 2.

Further, the basic assumption is that the UE uses a fixed frame structure according to Fig. 3. A primary hopping sequence determines the frequency a UE is using during an initial guaranteed DL part of a frame and enables allocating different narrow bands to different UEs, by configuring them to use different primary hopping sequences. That is, an identity of the UE makes the association with the assigned primary hopping sequence. Signalling received during guaranteed DL part of the frame provides the UE with scheduling information related to the remainder of the frame, including which frequencies to occupy. For two UEs to consistently be allocated different narrow bands during the guaranteed downlink period and across multiple eNB hops, their respective primary hopping sequences may be designed so they do not overlap in time and frequency. The primary hopping sequence follows the eNB frequency hopping such that each primary hop frequency is contained within the eNB transmitting frequency used for the hop.

An example of a hopping sequence designed to fulfil the criteria discussed in the section above is shown in Fig. 4.

From a regulatory point of view, and since the frequency hopping scheme for the UE is dynamically scheduled, the dynamic scheduling needs to consider the regulatory requirement on frequency occupation. For this reason, it is a further desirable property of the primary hopping sequence to use each narrowband with as close as possible to equal probability on average. In the example of Fig. 4, the primary hopping sequences are devised so that all UEs use different narrow bands for their guaranteed downlink periods of the different frames.

To use the communication channel efficiently, it may be beneficial for the scheduler to have the possibility to influence the primary hopping sequence used by each UE, e.g. through semi-static (Radio Resource Control, RRC) signalling. However, as a new UE attaches to the system, there may be a limited time -period for which such signalling has not yet been received. Therefore, it may be beneficial to define an initial - hopping sequence which the UE can use to perform frequency hopping until the point when semi-static signalling assigns a specific primary hopping sequence.

The initial primary hopping sequence may be semi-statically indicated by the eNB through a mapping function that may depend on any arbitrary combination of, PSS/SSS sequence, PCI, system information, RNTI or IMSI.

UEs in connected mode need to receive e.g. broadcast message which is typically transmitted by eNB in initial hopping sequence. But UE may not be able to monitor both the initial hopping sequence and the UE specific primary hopping sequence. In one example, eNB may send duplicates of what is transmitted in initial hopping sequence to specific UE via primary hopping sequence which creates overhead in resource utilization. In another example eNB may indicate UE to hop to initial hopping sequence via a primary hopping channel or anchor channel when UE is in connected state. Alternatively, connected UE may determine to use initial hopping sequence to receive e.g. system information when needed, with the risk of missing DL message from the UE specific primary hopping channels. The primary hopping sequence may also be defined as a combination of a specific primary hopping sequence and a primary hopping sequence phase. Here the primary hopping sequence phase, serves to shift the timing of any arbitrary primary hopping sequence, relative to a reference timing, for example by one frame duration forwards in time.

Flow charts for examples of the UE behaviour are shown in Fig. 5, Fig. 6 and Fig. 7. Fig. 5 illustrates an example for the UE during initial acquisition. Fig. 6 illustrates an example for the UE during random access. Fig. 7 illustrates an example for the UE during connected mode.

Flow charts for examples of the eNB behaviour are shown in Fig. 8, Fig. 9 and

Fig. 10. Fig. 8 illustrates an example for the eNB during random access. Fig. 9 illustrates an example for the eNB for paging. Fig. 10 illustrates an example for the eNB during connected mode.

Basically, the electronic transceiver device performs a method as illustrated in the flow chart of Fig. 11. That is, the electronic transceiver device performs 1100 frequency hopping according to a first pattern during a first part of a frame, which part is reserved for downlink communication. That enables the electronic transceiver device to receive 1102 scheduling information, from which it derives 1104 a second pattern which to use for a second part of the frame where the electronic transceiver device performs 1106 frequency hopping according to the second pattern. The first and second patterns are different in at least one sense, such as sequence, rate, etc.

From a similar basic view, the network node a method as illustrated in the flow chart of Fig. 12. That is, the network node determines 1200 a first pattern which the network node uses for performing 1202 frequency hopping during the first part of the frame. The network node also selects 1204 a second pattern, which the network node includes information about in scheduling information, which is sent 1206 during the first part of the frame.

Fig. 13 is a block diagram schematically illustrating an electronic transceiver device 1300, such as a UE, according to an embodiment. The electronic transceiver device 1300 comprises an antenna arrangement 1302, a receiver 1304 connected to the antenna arrangement 1302, a transmitter 1306 connected to the antenna arrangement 1302, a processing element 1308 which may comprise one or more circuits, one or more input interfaces 1310 and one or more output interfaces 1312. The interfaces 1310, 1312 can be user interfaces and/or signal interfaces, e.g. electrical or optical. The electronic transceiver device 1300 is arranged to operate in a cellular communication network. In particular, by the processing element 1308 being arranged to perform the embodiments demonstrated with reference to Figs 5 to 7 and 11, the electronic transceiver device 1300 is capable of frequency hopping as demonstrated above. The processing element 1308 can also fulfil a multitude of tasks, ranging from signal processing to enable reception and transmission since it is connected to the receiver 1304 and transmitter 1306, executing applications, controlling the interfaces 1310, 1312, etc.

Fig. 14 is a block diagram schematically illustrating a network node 1400, such as an eNB, according to an embodiment. The network node 1400 comprises an antenna arrangement 1401a, a transceiver 1401 connected to the antenna arrangement 1401a, a processor 1402, a memory 1404 and one or more interfaces 1406. The processor 1402 is arranged to perform the embodiments demonstrated with reference to Figs 8 to 10 and 12, wherein the network node 1400 is capable of managing frequency hopping as demonstrated above. The processing element 1402 can also fulfil a multitude of tasks, ranging from signal processing to enable reception and transmission since it is connected to the receiver transceiver 1401, executing applications, controlling the interfaces 1406, etc.

The methods according to the present disclosure is suitable for implementation with aid of processing means, such as computers and/or processors, especially for the case where any of the processing elements 1308, 1402 demonstrated above comprises a processor handling frequency hopping. Therefore, there is provided computer programs, comprising instructions arranged to cause the processing means, processor, or computer to perform the steps of any of the methods according to any of the embodiments described with reference to Figs 5 to 12. The computer programs preferably comprise program code which is stored on a computer readable medium 1500, as illustrated in Fig. 15, which can be loaded and executed by a processing means, processor, or computer 1502 to cause it to perform the methods, respectively, according to embodiments of the present disclosure, preferably as any of the embodiments described with reference to Figs 1 to 6. The computer 1502 and computer program product 1500 can be arranged to execute the program code sequentially where actions of the any of the methods are performed stepwise. The processing means, processor, or computer 1502 is preferably what normally is referred to as an embedded system. Thus, the depicted computer readable medium 1500 and computer 1502 in Fig. 15 should be construed to be for illustrative purposes only to provide understanding of the principle, and not to be construed as any direct illustration of the elements.

Claims

1. A method performed by an electronic transceiver device arranged to operate in a cellular communication system enabling operation in unlicensed bands and having a frame structure for communication between the electronic transceiver device and a network node of the cellular communication system where a first part of a frame is reserved for downlink communication and a second part of the frame is available both for downlink and uplink communication, the method comprising

performing frequency hopping reception or transmission according to an initial hopping sequence which the electronic transceiver device uses until semi-static signalling assigns a specific primary hopping sequence; and

after receiving indication of the primary hopping sequence, performing frequency hopping reception or transmission according to a second pattern for the second part of the frame,

wherein second pattern is a frequency hopping sequence.

2. The method of claim 1, wherein the initial hopping sequence is pre- configured.

3. The method of claim 2, wherein the pre-configured initial hopping sequence is determined from a mapping from any of

synchronisation signals,

cell identity,

system information, and

subscriber identity, or

any combination thereof.

4. The method of any one of claims 1 to 3, comprising performing frequency hopping reception according to a first pattern for the first part of the frame wherein scheduling information is received, wherein the second pattern is derived from the scheduling information and the first pattern is a frequency hopping sequence.

5. The method of claim 4, wherein the first pattern is pre-configured.

6. The method of claim 5, wherein the pre-configured first pattern is determined from a mapping from any of

synchronisation signals,

cell identity,

system information, and

subscriber identity,

Radio Resource Control signalling,

Msg2 or Msg4 signalling, or

any combination thereof.

7. The method of claim 5, wherein the pre-configured first pattern is a default initial frequency hopping sequence.

8. A computer program comprising instructions which, when executed on a processor of an electronic transceiver device, causes the electronic transceiver device to perform the method according to any of claims 1 to 7.

9. A method performed by a network node arranged to operate in a cellular communication system enabling operation in unlicensed bands and having a frame structure for communication between an electronic transceiver device and the network node of the cellular communication system where a first part of a frame is reserved for downlink communication and a second part of the frame is available both for downlink and uplink communication, the method comprising

performing frequency hopping reception or transmission between the network node and the electronic transceiver device according to an initial hopping sequence until semi-static signalling assigns the electronic transceiver device a specific primary hopping sequence;

after assigning the primary hopping sequence, performing frequency hopping transmission according to a second pattern for reception or transmission between the network node and the first electronic device during the second part of the frame, wherein the second pattern for frequency hopping for the first electronic transceiver device is used for the second part of the frame,

wherein the second pattern is a frequency hopping sequence.

10. The method of claim 9, wherein the initial hopping sequence is pre- configured.

11. The method of claim 10, wherein the pre-configured initial hopping sequence is determined from a mapping from any of

synchronisation signals,

cell identity,

system information, and

subscriber identity, or

any combination thereof.

12. The method of any one of claims 9 to 11, comprising performing frequency hopping transmission according to a first pattern for the first part of the frame wherein scheduling information is transmitted, wherein the second pattern is derivable from the scheduling information and the first pattern is a frequency hopping sequence.

13. The method of any one of claims 9 to 12, wherein the first pattern is pre- configured.

14. The method of claim 13, wherein the pre-configured first pattern is determined from a mapping from any of

synchronisation signals,

cell identity,

system information, and

subscriber identity,

Radio Resource Control signalling,

Msg2 or Msg4 signalling, or

any combination thereof.

15. The method of claim 13, wherein the pre-configured first pattern is a default initial frequency hopping sequence.

16. The method of any one of claims 9 to 15, wherein the first pattern is selected among a set of frequency hopping sequences comprising at least two sequences arranged to not mutually overlap in time and frequency.

17. The method of claim 16, wherein the set of sequences is arranged such that probability of occupying a frequency is equal on average in each frequency hopping cycle.

18. A computer program comprising instructions which, when executed on a processor of a network node, causes the network node to perform the method according to any of claims 9 to 17.

19. An electronic transceiver device arranged to operate in a cellular communication system enabling operation in unlicensed bands and having a frame structure for communication between the electronic transceiver device and a network node of the cellular communication system where a first part of a frame is reserved for downlink communication and a second part of the frame is available both for downlink and uplink communication, wherein the electronic transceiver device is arranged to perform the method of any of one of claims 1 to 7.

20. A network node arranged to operate in a cellular communication system enabling operation in unlicensed bands and having a frame structure for communication between an electronic transceiver device and the network node of the cellular communication system where a first part of a frame is reserved for downlink communication and a second part of the frame is available both for downlink and uplink communication, wherein the network node is arranged to perform the method of any one of claims 9 to 17.