GB2491401A

GB2491401A - Control channels are mapped onto two frequency blocks and transmitted utilising pair-wise frequency hopping on a shared spectrum

Info

Publication number: GB2491401A
Application number: GB1109310.1A
Authority: GB
Inventors: Sami-Jukka Hakola; Timo Koskela; Samuli Turtinen
Original assignee: Renesas Mobile Corp
Current assignee: Renesas Electronics Corp
Priority date: 2011-06-03
Filing date: 2011-06-03
Publication date: 2012-12-05
Anticipated expiration: 2031-06-03
Also published as: GB2491401B; GB201109310D0

Abstract

Controlling 202 a transmitter to map comÂmon and dedicated control channels, e.g. for cellular (LTE-based) transmissions, on two frequency blocks and controlling 204 the transmitter to transmit the frequency blocks utilising pair-wise frequency hopping on a shared specÂtrum, e.g. license-exempt or unlicensed frequency bands. The transmitter may be further controlled to transmit on shared data channels using Listen-Before-Talk or channel contention between the devices communicating on the shared spectrum. Synchronisation signals may be mapped to the two frequency blocks. The transmitter may be further controlled to utilize frequency bands located between identified Wireless Local Area Network (WLAN) channels in the transmission of the two frequency blocks.

Description

Apparatus and method for communication

Field of the Invention

The invention relates generally to wireless communications networks.

More particular, but not exclusively, some embodiments of the invention relate to the control of a transmitter in a communications network while other embodiments of the invention relate to the control of a receiver in a communications network.

Background of the Invention

With the ever increasing demand for increasing data rates and higher quali-ty services in the world of mobile communications comes ever increasing demand for better performance of cellular network infrastructures. The increased spectrum re-quirements due the increased data traffic drives operators to seek offloading solutions for their traffic, via local nodes providing local access to the Intemet, to prevent con-gesting their own core network. A wide variety of diverse sizes of cells and connected devices are proposed in addition to traditional macro and microcells. However, the available frequency resources are limited and the need for efficient use of the resources is essential.

Traditional solutions to improve spectrum efficiency may not support the predicted data traffic in the future. Thus, operators, network and device manufacturers and other players in the field are considering the utilization of license-exempt (LE) or unlicensed frequency bands along with costly licensed spectrum. The LE spectrum can also be called shared spectrum'. Shared spectrum is only lightly regulated; users do not need licenses to exploit it. From the cellular traffic point of view, an interesting shared spectrum band opportunity is Industrial, Scientific and Medical (ISM) bands.

The ISM bands are widely used for WLAN and Bluetooth® communications. The ISM bands allow both standardized systems and proprietary solutions to be deployed onto spectrum as far as regulations are followed. The regulations define maximum trans-mission powers and certain rules for the hopping based systems for the operation on the band.

Currently it is challenging for many cellular systems, such as the third and fourth generation systems long term evolution (LTE, known also as E-UTRA) and long term evolution advanced (LTE-A), to utilise ISM bands, for example, due to re-quired continuous and synchronous resource allocation for control channels both in downlink and upliftk transmission directions.

Summary of the Invention

According to an aspect of the present invention, there is provided an appa- ratus for controlling a transmitter in a communication system, the apparatus compris-ing processing means arranged to: control a transmitter to map common and dedicated control channels on two frequency blocks; and control the transmitter to transmit the frequency blocks utilising pair-wise frequency hopping on a shared spectrum.

According to another aspect of the present invention, there is provided a method in a communication system, comprising: controlling a transmitter to map common and dedicated control channels on two frequency blocks; and controlling the transmitter to transmit the frequency blocks utilising pair-wise frequency hopping on a shared spectrum.

According to an aspect of the present invention, there is provided an appa- ratus for controlling a receiver in a communication system, the apparatus compri-singproccssing means arranged to: control a receiver to receive common and dedicated control channels mapped to two frequency blocks utilising pair-wise frequency hop-ping on a shared spectrum.

According to another aspect of the present invention, there is provided a method in a communication system, comprising: controlling a receiver to receive common and dedicated control channels mapped to two frequency blocks utilising pair-wise frequency hopping on a shared spectrum.

According to another aspect of the present invention, there is provided a computer program comprising program code means adapted to perform the steps of either of the preceding methods when the program is run on a computer.

According to yet another aspect of the present invention there is provided a transmitter arrangement comprising an apparatus for controlling a transmitter as de-scribed above.

According to another aspect of the present invention there is provided a re-ceiver arrangement comprising an apparatus for controlling a receiver as described above.

Brief Description of the Drawings

Embodiments of the present invention are described below, by way of ex-ample only, with reference to the accompanying drawings, in which Figure 1 is a block diagram that illustrates an example of a communication environment; Figure 2A and 2B are flowcharts illustrating processes according to embo-diments of the invention; Figure 3 is a flow diagram that illustrates another process according to an embodiment of the invention; Figure 4A is a diagram that illustrates an example of the shared spectrum; Figure 4B is a diagram that illustrates an example of the use of pair-wise frequency hopping; and Figures 5A and SB are high level block diagrams that illustrate examples of apparatuses applying embodiments of the invention.

Detailed Description of the Invention

Embodiments of the invention are applicable to any base station, user equipment (UE), server, corresponding component, and/or to any communications system or any combination of different communications systems that support required functionality, as will be described hereinafter.

The protocols used, the specifications of communication systems, servers and user terminals, especially in wireless communications, develop rapidly. Such de-velopment may require alterations or enhancements to an embodiment. Therefore, all words and expressions should be interpreted broadly and they are intended to illustrate, not to restrict, embodiments.

Many different radio protocols for use in communications systems exist.

Some examples of different communication systems are the universal mobile tele-communications system (UMTS) radio access network (UTRAN or E-UTRAN), long term evolution (LTE, known also as E-UTRA), long term evolution advanced (LTE-A), Wireless Local Area Network (WLAN) based on IEEE 802.1 istardard, worldwide interoperability for microwave access (WiMAX), Bluetooth®, personal communica- tions services (PCS) and systems using ultra-wideband (UWB) technology. IEEE re- fers to the Institute of Electrical and Electronics Engineers. At least some embodi-ments of the present invention are relevant to one or more of these protocols.

Figure 1 illustrates a simplified view of a communications environment showing some of the main elements and functional entities (all being logical units whose implementation may differ from what is shown). The connections shown in Figure 1 are logical connections; the actual physical connections may be different. It will be apparent to a person skilled in the art that the systems also comprise other func-tions and structures. It will also be appreciated that the particular functions, structures, elements and the protocols used in or for communications are incidental to the actual invention. Therefore, they need not to be discussed in more detail herein.

is In the example of Figure 1, a radio system based on LTE/SAE (Long Term EvolutionlSystem Architecture Evolution) network elements is shown. However, as already alluded to the embodiments described in these examples are not limited to the LTE/SAE radio systems but can also be implemented in other radio systems.

The simplified example of a network of Figure 1 comprises a SAE Gate-way (SAE GW) 100 and a Mobility Management Entity (MME) 102. The SAE GW provides a connection to Internet 104. Figure 1 shows an Enhanced node B (eNodeB) 106 serving a macro cell 108. In addition, a local area base stations or Home NodeB (FINB) 110 with a corresponding coverage area 112 is shown. In this example, the HINB 110 and the eNodeB 106 are connected to the SAE GW 100 and to the MME 102.

In the example of Figure 1, a first item of user equipment (UE) 114 is camped on the HNB 110. A second item of UE 116 is camped on the eNodeB 106.

Furthermore, a wireless local area network (WLAN) base station 118 is transmitting with a coverage area 120.

The eNodeB of a communication system may host the functions for Radio Resource Management: Radio Bearer Control, Radio Admission Control, Connection Mobility Control, Dynamic Resource Allocation (scheduling). The MME 102 is re-sponsible for overall UE control in mobility, sessionlcall and state management with assistance of the eNodeBs through which the UEs connect to the network. The SAE GW 100 is an entity configured to act as a gateway between the network and other parts of communications network such as the Internet for example. The SAE GW 100 may be a combination of two gateways, a serving gateway (S-GW) and a packet data network gateway (P-GW).

As used herein, user equipment, or UE, refers to a portable computing de- vice. Such computing devices include wireless mobile communication devices operat-ing with or without a subscriber identification module (SIM), including, but not limited to, the following types of devices: mobile phone, smartphone, personal digital assistant (PDA), handset, laptop computer, and the like.

In an embodiment, at least some of the above connections between NodeB's and UEs utilisc LE spectrum, which may, for example, be the same as the spectrum used by the WLAN base station 118.

is The regulations applying to the use of LE spectrum require different sys- tems to use the available resources in a fair manner without causing excessive interfe-rence to other systems using the same resources.

In an embodiment, Listen-Before-Talk (LBT), or channel contention be- tween the devices communicating on the shared spectrum, is used to reduce interfe- rence. LBT or channel contention may require a device to listen, monitor and/or meas-ure the usage of a channel for a given time before making a decision on whether to transmit on the channel or not. In an embodiment, the device monitors energy level on a channel and, if the level is above a given threshold, it may determine that the channel is in use by another device. If the channel or spectrum is used by another device, the transmitter is configured to abstain from transmitting or select a different channel.

As most cellular systems require that control channel transmissions are continuous and synchronous, the restricted use of resources on shared spectrum presents a challenge as the resource allocation for control channels both in downlinlc and uplink transmission directions is problematic as it cannot be guaranteed in ad-vance. Likewise, if LBT type of channel access is utilized, the resource allocation for synchronization signals, critical control channel signalling like HARQ (Hybrid auto-matic repeat request) feedback is challenging as there is no certainty that resources for the required HARQ feedback for the earlier data transmission can be obtained.

In LTE based systems, dedicated and common control channels include Physical Broadcast Channel (PBCH), Physical Control Format Indicator Channel (PCFICH), Physical Downlink Control Channel (PDCCH), Physical HARQ Indicator Channel (PHICH), Physical Uplink Shared Channel (PUSCH) and synchronization signals.

As already explained, embodiments of the invention are not limited to LTE based systems. The above channels and numerical values below are provided by way of a non-limiting example only.

In an embodiment, it is proposed to transmit dedicated and common con-trol channels using frequency hopping. In LTE based systems, synchronization signals are currently transmitted among the symbols of Physical Downlink Shared Channel (PDSCH). In the embodiment, the synchronization signals are transmitted in the con-is trol channel region utilizing frequency hopping. The regulations on ISM bands require that the maximum continuous frequency bandwidth for the hopping system is less than 1 MHz and that the hopping system should hop pseudo-randomly between at least 15 non-overlapping frequency channels. As synchronization signals and PBCH on downlink require a 1.08 MHz bandwidth (6 Physical Resource Blocks (PRB)), the pre-sent LTE method of mapping control channels onto radio resources cannot be applied.

Figure 2A is a flowchart illustrating an embodiment of the invention. The embodiment starts at step 200.

In step 202, a transmitter is controlled to map common and dedicated con-trol channels on two frequency blocks.

In step 204, the transmitter is controlled to transmit the frequency blocks utilising pair-wise frequency hopping on a shared spectrum.

The process ends in step 206.

In the embodiment, it is proposed that control channel transmission on downlink and uplink utilize a pair-wise hopping of frequency pieces. When applying the embodiment to LTE based system, the bandwidth of the frequency blocks the con-trol channels are mapped to could be three PRBs each. Three PRBs equal to 504 KHz and thus combining two pieces a virtual 6 PRB frequency chunk is obtained from which a rcccivcr can construct a signal having a 1.08 MHz bandwidth. Thus it is possi-ble to reuse LTE common channels in their current format mapped in a discontinuous way onto subcarriers in the frequency domain.

Figure 2B is a flowchart illustrating an embodiment of the invention ap-plied in a receiver. The embodiment starts at step 210.

In step 212, a receiver is controlled to receive common and dedicated con-trol channels mapped to two frequency blocks utilising pair-wise frequency hopping on a shared spectrum.

The process ends in step 214.

Figure 3 is a flowchart illustrating an embodiment of the invention. The embodiment starts at step 300.

In step 302, a transceiver is controlled to detect and identify WLAN chan-nels on given shared spectrum. The shared spectrum may be the ISM band on 2.4 or 5 GHz, for example. In the embodiment, downlinlc and uplink control channels are is transmitted using frequency hopping (continuously in time domain) between the iden-tified WLAN channels. Shared data channels for both downlink and uplink may be transmitted using LBT on identified WLAN channels. In LTE based systems, the shared data channels are PDSCH and PUSCH.

In step 304, a transceiver is controlled to map common and dedicated con-trol channels on two frequency blocks on a shared spectrum utilizing the frequency bands between the identified WLAN channels.

In step 306, the transceiver is controlled to transmit the frequency blocks utilising pair-wise frequency hopping utilizing the frequency bands between the identi-fied WLAN channels. Thus, the frequencies used in the transmission frequency blocks hop using the same hopping pattern. The hopping pattern may be a predefined pattern or one of a set of predefined hopping patterns. In general, the hopping patterns are de-fined by a base station or eNodeB, or by another network element of a communication system. When a UE is switched on it searches for control channel transmissions of an eNodeB. For example, when the UE finds a control channel transmitted by an eNodeB it may obtain information of the hopping pattern from the eNodeB.

For example in the 2.4 GHz ISM band, there are three non-overlapping WLAN channels each using a bandwidth of 20/22 MHz. Taking into account a normal effective bandwidth of 83.5 MHz in 2.4 GHz ISM (in some countries, the 2.4 GHz ISM can utilize 100 MHz, and thus there are also 14 WLAN channels), it is possible to support 15 non-overlapping frequency resources for the hopping control channel de- sign. In addition, using the pair-wise hopping for the control channels and having hop-ping frequency of 1 ms (1 sub frame with two slots) allows a slot based hopping for PUCCH similar to current LTE based systems.

As mentioned above, in contrast to current LTE synchronization, signals are not transmitted among the symbols of PDSCH, but in the control channel region utilizing the pair-wise hopping. In the embodiment, the hopping pattern and deploy- ment of synchronization signals is designed so that the receiver (such as a UE) requir-ing the synchronization signals would not need to use the whole bandwidth of the ISM band to detect the synchronization signals in an initial search phase of the LTE eNB on a ISM band. One option is to maintain synchronization signals in one region of the ISM band. The region may be the largest frequency region not used by the WLAN of is the ISM band. For example, if the synchronization signals are transmitted every 5 ms, the hopping patterns may be so that control channel transmission takes place at least every S ms on certain resource region (the largest frequency region not used by the WLAN). For example, when channels 1, 6 and 11 are used by a WLAN system, the largest frequency region would be from 2470 to 2480 MHz.

In step 308, the transceiver is controlled to transmit shared data channels using LBT on identified WLAN channels. As described above, in LBT a transceiver listens or measures the usage of a channel before making the decision whether to transmit on the channel or not. If the channel or spectrnm is used by another device, the transmitter is configured to abstain from transmitting or select a different channel.

In this way, the transmission does not interfere with WLAN transmissions on the same channel.

The process ends in 310.

Figure 4A illustrates an example of the shared spectrum. The figure shows WLAN channels on the 2.4GHZ ISM frequency band. Three WLAN channels 400, 402, 404 are illustrated. The channels may be identified as channels 1, 6 and 11. The numbering varies in different regions, however. Between the WLAN channels there are guard bands 406, 408, 410 and 412, which have bandwidths 1MHz, 3 MHz, 3MHz and 10 MHz, respectively.

In an embodiment, the common and dedicated control channels are mapped to two frequency blocks and transmit the frequency blocks utilising pair-wise fre-quency hopping on the frequency bands 406, 408, 410 and 412, which are between the WLAN channels. The frequency bands 406, 408, 410 and 412 form a 17MHZ virtual frequency spectrum 414 which is utilised when transmitting the control channels both in the downlink and the uplink direction. In LTE-based systems, PUCCH is transmit-ted in the uplink direction and PDCCH, PCFICH, PHICH, PBCH and synchronization signals are transmitted in the downlink direction. The transmissions utilize Time Divi-sion Duplex (TDD), where different transmission directions use the same frequency resources but are separated in time.

Figure 4B illustrates an example of the use of the pair-wise frequency hop- ping of the control channels' transmission on the shared spectrum. The control chan-is nels are mapped to two frequency blocks where the bandwidth of each frequency block is three PRBs corresponding to 504 KTHIz. Figure 4B shows a pair 420 of frequency blocks. The blocks are frequency hopping in time to positions 422 and 424 in the vir-tual frequency band 414. Only two first hopping positions are illustrated in Figure 4B.

In an embodiment, the synchronization signals are placed in a frequency block that is located in the largest region 412.

Figure 5A illustrates a simplified example of an apparatus applying em-bodiments of the invention. In some embodiments, the apparatus may be an eNodeB or user equipment of a communications system, for example, as illustrated in Figure 1.

It should be understood that the apparatus is depicted herein as an example according to some embodiments. It will be apparent to a person skilled in the art that the apparatus may also comprise other functions and/or structures and not all described functions and structures are required. Although the apparatus has been depicted as one entity, different modules and memory may be implemented in one or more physical or logical entities.

The apparatus of the example includes a control circuitry 500 configured to control at least part of the operation of the apparatus.

The apparatus comprises a memory 502 for storing data. Furthermore the memory stores software 504 executable by the control circuitry 500. The memory in this instance is integrated in the control circuitry.

The apparatus comprises a transceiver 506. The transceiver is operationally connected to the control circuitry 500, and to an antenna arrangement (not shown) in a known way.

The software 504 comprises a computer program comprising program code means adapted to cause the control circuitry 500 of the apparatus to control the trans-ceiver 506 to map common and dedicated control channels on two frequency blocks and control the transceiver to transmit the frequency blocks utilising pair-wise fre-quency hopping on a shared spectrum.

The apparatus further comprises interface circuitry 508 configured to con-nect the apparatus to other devices and network elements of a communications system, for example to core. This applies especially if the apparatus is an eNodeB or a base station or a respective network element. The interface provides a wired or wireless connection to the communications network. The apparatus may be in connection with core network elements, eNodeBs, HINBs and with other respective apparatuses of the communication systems.

The apparatus further comprises a user interface 510 operationally con-nected to the control circuitry 500. The user interface comprises a display, a keyboard or keypad, a microphone and a speaker, for example. This applies especially if the ap-paratus is UE or a respective network element.

Figure SB illustrates a a simplified example of an apparatus applying em-bodiments of the invention. The apparatus may be an eNodeB or user equipment of a communications system.

The apparatus of the example includes a control circuitry 520 configured to control at least part of the operation of the apparatus.

The apparatus comprises a memory 522 for storing data. Furthermore the memory stores software 524 executable by the control circuitry 520. The memory in this instance is integrated in the control circuitry.

The apparatus comprises a transceiver 526. The transceiver is operationally connected to the control circuitry 520, and to an antenna arrangement (not shown) in a known way.

The software 524 comprises a computer program comprising program code means adapted to cause the control circuitry 520 of the apparatus to control the trans- ceiver 526 to receive common and dedicated control channels mapped to two fre- quency blocks utilising pair-wise frequency hopping on a shared spectmm. The trans-ceiver is configured to utilise more than one non-overlapping frequency band when receiving the two frequency blocks utilising pair-wise frequency hopping.

is In an LTE based system, the bandwidth of the frequency blocks the control channels are mapped to could be three PRBs each. Three PRBs equal to 504 1KHz. The transceiver 526 is configured to receive frequency blocks and the software 524 con-trols the apparatus to combine the two received frequency blocks and construct a signal having 1.08 MHz bandwidth. Thus it is possible to reuse LTE common channels in their current format mapped in a discontinuous way onto subcarriers in the frequency domain.

The apparatus further comprises interface circuitry 528 configured to con-nect the apparatus to other devices and network elements of communication system, for example to core. This applies especially if the apparatus is an eNodeB or a base station or respective network element. The interface provides either a wired or wireless connection to the communications network. The apparatus may be in connection with core network elements, eNodeBs, FINBs and with other respective apparatuses of communication systems.

The apparatus further comprises a user interface 530 operationally con-nected to the control circuitry 520. The user interface comprises a display, a keyboard or keypad, a microphone and a speaker, for example. This applies especially if the ap-paratus is user equipment or respective network element.

In any event, other embodiments of the invention may be implemented us- ing more, fewer or a different arrangement of components to those described in rela-tion to Figures 5A and 5B.

The steps and related functions described in the above and attached figures are in no absolute chronological order, and some of the steps may be performed simul- taneously or in an order differing from the given one. Other functions can also be exe-cuted between the steps or within the steps. Some of the steps can also be left out or replaced with a corresponding step.

The apparatuses or controllers that are able to perform the above-described steps may be implemented as an electronic digital computer, which may comprise a working memory (RAM), a central processing unit (CPU), and a system clock. The CPU may comprise a set of registers, an arithmetic logic unit, and a controller. The controller is controlled by a sequence of program instructions transferred to the CPU from the RAM. The controller may contain a number of microinstructions for basic operations. The implementation of microinstructions may vary depending on the CPU design. The program instructions may be coded by a programming language, which may be a high-level programming language, such as C, Java, etc., or a low-level pro- gramming language, such as a machine language, or an assembler. The electronic digi-tal computer may also have an operating system, which may provide system services to a computer program written with the program instructions.

As used in this application, the term circuitry' refers to all of the follow- ing: (a) hardware-only circuit implementations, such as implementations in only ana-log and/or digital circuitry, and (b) combinations of circuits and software (and/or firmware), such as (as applicable): (i) a combination of processor(s) or (ii) portions of processor(s)/software including digital signal processor(s), software, and memory(ies) that work together to cause an apparatus to perform various functions, and (c) circuits, such as a microprocessor(s) or a portion of a microprocessor(s), that require software or firmware for operation, even if the software or firmware is not physically present.

This definition of circuitry' applies to all uses of this term in this applica-tion. As a further example, as used in this application, the term circuitry' would also cover an implementation of merely a processor (or multiple processors) or a portion of a processor and its (or their) accompanying software and/or firmware, The term cir-cuitry' would also cover, for example and if applicable to the particular element, a baseband integrated circuit or applications processor integrated circuit for a mobile phone or a similar integrated circuit in a server, a cellular network device, or another network device.

An embodiment provides a computer program embodied on a distribution medium, comprising program instructions which, when loaded into an electronic appa-ratus, are configured to control the apparatus to execute the embodiments described above.

The computer program may be in source code form, object code form, or in some intermediate form, and it may be stored in some sort of carrier, which may be any entity or device capable of carrying the program. Such carriers include a record medium, computer memory, read-only memory, and a software distribution package, for example. Depending on the processing power needed, the computer program may be executed in a single electronic digital computer or it may be distributed amongst a is number of computers.

The apparatus may also be implemented as one or more integrated circuits, such as application-specific integrated circuits ASIC. Other hardware embodiments are also feasible, such as a circuit built of separate logic components. A hybrid of these different implementations is also feasible. When selecting the method of implementa-tion, a person skilled in the art will consider the requirements set for the size and power consumption of the apparatus, the necessary processing capacity, production costs, and production volumes, for example.

It will be obvious to a person skilled in the art that, as technology ad-vances, the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.

Claims

Claims 1. An apparatus for controlling a transmitter in a communications system, the apparatus comprising processing means arranged to: control a transmitter to map common and dedicated control channels onto two frequency blocks; and control the transmitter to transmit the frequency blocks utilising pair-wise frequency hopping on a shared spectrum.
2. The apparatus of claim 1, wherein the processing means is arranged to control the transmitter to transmit on shared data channels using Listen-Before-Talk.
3. The apparatus of claim 1 or 2, wherein the processing means is arranged to control the transmitter to utilise more than one non-overlapping frequency resource when transmitting the two frequency blocks utilising pair-wise frequency hopping.
4. The apparatus of any preceding claim, wherein the processing means is arranged to map synchronisation signals to the two frequency blocks.
5. The apparatus of claims 3 and 4, wherein the processing means is ar-ranged to control the transmitter to transmit the synchronisation signals in the largest frequency resource.
6. The apparatus of any preceding claim, wherein the processing means is arranged to identify wireless local area network channels of a given frequency band and control the transmitter to utilise frequency bands located between the identified wireless local area network channels in the transmission of the two frequency blocks.
7. The apparatus of any preceding claim, wherein the processing means is arranged to control the transmitter to transmit shared data channels using Listen-Before-Talk on identified wireless local area network channels.
8. An apparatus for controlling a receiver in a communications system, the apparatus comprising processing means arranged to: control a receiver to receive common and dedicated control channels mapped to two frequency blocks utilising pair-wise frequency hopping on a shared spectrum.
9. The apparatus of claim 8, wherein the processing means is arranged to control the receiver to utilise more than one non-overlapping frequency bands in when receiving the two frequency blocks utilising pair-wise frequency hopping.
10. A method in a communication system, comprising: controlling a transmitter to map common and dedicated control channels on two frequency blocks; and controlling the transmitter to transmit the frequency blocks utilising pair-wise frequency hopping on a shared spectrum.
11. The method of claim 10, further comprising: controlling the transmitter to transmit on shared data channels using Listen-Before-Talk.
12. The method of claim 10 or 11, further comprising: controlling the transmitter to utilise more than one non-overlapping frequency resources in when transmitting the two frequency blocks utilising pair-wise frequency hopping.
13. The method of any of claims 10 to 12, further comprising: mapping synchronisation signals to the two frequency blocks.
14. The method of claims 12 and 13, further comprising: controlling the transmitter to transmit the synchronisation signals in the largest frequency resource.
15. The method of any of claims 10 to 14, further comprising: identifying wireless local area network channels of a given frequency band and controlling the transmitter to utilise frequency bands located between the identified wireless local area network channels in the transmission of the two frequency blocks.
16. The method of any of claims 10 to 15, further comprising: controlling the transmitter to transmit shared data channels using Listen-Before-Talk on identified wireless local area network channels.
17. A method in a communication system, comprising: controlling a receiver to receive common and dedicated control channels mapped to two frequency blocks utilising pair-wise frequency hopping on a shared spectrum.
18. The method of claim 17, further comprising: controlling the receiver to utilise more than one non-overlapping frequency band when receiving the two fre-quency blocks utilising pair-wise frequency hopping.
19. A computer program comprising program code means adapted to per-form the steps of any of claims 10 to 18 when the program is run on a computer.
20. A transmitter arrangement comprising an apparatus according to any one of claims ito 7.
21. A receiver arrangement comprising an apparatus according to either one of claims 8 and 9.