WO2013030732A1

WO2013030732A1 - Apparatus and method for communication

Info

Publication number: WO2013030732A1
Application number: PCT/IB2012/054289
Authority: WO
Inventors: Sami-Jukka Hakola; Timo Koskela; Samuli Turtinen
Original assignee: Renesas Mobile Corporation
Priority date: 2011-08-26
Filing date: 2012-08-24
Publication date: 2013-03-07

Abstract

An apparatus for and a method of communication are provided, involving controlling the communication of a transceiver on shared data channels using a data channel slot comprising a sensing period and a data period and controlling a transceiver to communicate on common and dedicated control channels on a shared spectrum using control channel slots. Each control channel slot comprises a downlink part and an uplink part. The uplink part occurs at the same time as the sensing period of a data channel slot.

Description

Apparatus and method for communication

Technical Field

The invention finds application generally in wireless communication networks. Embodiments of the invention relate especially, though not exclusively, to an apparatus and a method operable in communication networks.

Background

With the ever increasing demand for increasing data rates and higher quality services in the world of mobile communications comes ever increasing demand for better performance of cellular network infrastructures. The increased spectrum requirements due the increased data traffic drives operators to seek offloading solutions for their traffic via local nodes providing local access to the Internet to prevent congesting 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 need for efficient use of the resources is essential.

Traditional solutions to improve spectrum efficiency may not be able to 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 them. 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® communication, for example. 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 transmission powers and certain rules for systems for the operation on the band.

Currently it is challenging to 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 required continuous and synchronous resource allocation for control channels both in downlink and uplink transmission directions. Summary

According to an aspect of the present invention, there is provided an apparatus operable in a communication system to: control the communication of a transceiver on shared data channels using a data channel slot comprising a sensing period and a data period; and control a transceiver to communicate on common and dedicated control channels on a shared spectrum using control channel slots, each comprising a downlink part and an uplink part, wherein the uplink part occurs at the same time as the sensing period of a data channel slot.

According to another aspect of the present invention, there is provided a method in a communication system, comprising: controlling the communication of a transceiver on shared data channels using a data channel slot comprising a sensing period and a data period; and controlling a transceiver to communicate on common and dedicated control channels on a shared spectrum using control channel slots, each control channel slot comprising a downlink part and an uplink part, wherein the uplink part occurs at the same time as the sensing period of a data channel slot.

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

According to yet another aspect of the present invention there is provided a transceiver arrangement comprising an apparatus for controlling a transceiver as described above.

Brief Description of the Drawings

Embodiments of the present invention are described below, by way of example only, with reference to the accompanying drawings, in which

Figure 1 is a schematic diagram illustrating an example of a communication environment;

Figure 2A and 2B are flowcharts illustrating embodiments of the invention;

Figure 3 is a flowchart illustrating an example of an operation in a communication environment;

Figures 4 A and 4B are timing diagrams illustrating examples of the shared spectrum; Figures 5A, 5B and 5C are block diagrams illustrating examples of different control channel slot configurations;

Figures 6A, 6B and 7 are flowcharts illustrating embodiments; and Figure 8 illustrates an example of an apparatus.

Detailed Description

Embodiments are applicable to any base station, user equipment (UE), server, corresponding component, and/or to any communication system or any combination of different communication systems that support required functionality.

The protocols used, the specifications of communication systems, servers and user terminals, especially in wireless communication, develop rapidly. Such development may require extra changes 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 telecommunications 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 lstardard, worldwide interoperability for microwave access (WiMAX), Bluetooth®, personal communications services (PCS) and systems using ultra-wideband (UWB) technology. IEEE refers to the Institute of Electrical and Electronics Engineers. Embodiments may relate to any one or more of these protocols.

Figure 1 illustrates a simplified view of a communication environment only showing some 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 is apparent to a person skilled in the art that the systems also comprise other functions and structures. It should be appreciated that the functions, structures, elements and the protocols used in or for communication are incidental to the actual invention. Therefore, they need not to be discussed in more detail here.

In the example of Figure 1, a radio system based on LTE/SAE (Long Term Evolution/System Architecture Evolution) network elements is shown. However, 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 Gateway 100 and a Mobility Management Entity (MME) 102. The SAE Gateway 100 provides a connection to Internet 104. Figure 1 shows an eNodeB 106 serving a macro cell 108. In addition, a local area base station or Home NodeB (HNB) 110 with a corresponding coverage area 112 is shown. In this example, the HNB 110 and the eNodeB 106 are connected to the SAE Gateway 100 and the MME 102.

In the example of Figure 1 , a UE 114 is camped on the HNB 110. Another UE 116 is camped on the eNodeB 106. Furthermore, a wireless local area (WLAN) base station 118 is transmitting with a respective coverage area 120.

The eNodeBs 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 responsible for the overall UE control in mobility, session/call 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 communication network such as the Internet for example. The SAE GW may be a combination of two gateways, a serving gateway (S-GW) and a packet data network gateway (P-GW).

UE refers to a portable computing device. Such computing devices include wireless mobile communication devices operating 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.

In an embodiment, at least some of the above connections between NodeBs and UEs utilise an unlicensed or shared spectrum which may be the same as the spectrum used by the WLAN base station 118 or by some other apparatus utilizing ISM spectrum.

The regulations applying to the usage of shared spectrum require different systems to use the available resources in a fair manner without causing excessive interference to other systems using the same resources.

In an embodiment, Listen-Before-Talk (LBT) or channel contention between the devices communicating on the shared spectrum is used to reduce interference. LBT or channel contention may require a device to listen, monitor or measure the usage of a channel for a given time before making the decision whether to transmit on the channel or not. In an embodiment, the device may monitor 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 is challenging as the resource allocation for control channels both in downlink and uplink transmission directions is problematic. In addition, if LBT type of channel access is utilized, the resource allocation for synchronization signals, critical control channel signalling like Hybrid automatic repeat request (HARQ) 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 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 one skilled in the art will appreciate embodiments of the invention are not limited to LTE based systems. The above channels and any numerical values below are mentioned as a non-limiting example only.

In an embodiment, it is proposed to transmit dedicated and common control channels using frequency hopping. In LTE based systems, synchronization signals are currently transmitted among the symbols of Physical Downlink Shared Channel (PDSCH). In an embodiment, the synchronization signals are transmitted in the control channel region utilizing frequency hopping. The regulations on ISM bands require the maximum continuous frequency bandwidth for the hopping system to be 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 existing LTE method of mapping control channels onto radio resources cannot be applied.

In an embodiment, it's 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 to which the control channels are mapped could be three PRBs each. Three PRBs are equal to 504 KHz and thus combining two pieces a virtual 6 PRB frequency chunk is obtained from which a receiver can construct a signal of 1.08 MHz bandwidth. Thus it could be possible to reuse LTE common channels in their current format mapped in a discontinuous way onto subcarriers in the frequency domain.

Figure 2A is a flowchart illustrating an embodiment of the invention. In an embodiment, the example relates to the operation of UE or a base station or an eNodeB. The embodiment starts at step 200.

In step 202, a transceiver is controlled to communicate on shared data channels using a data channel slot comprising a sensing period and a data period. A transceiver may be configured to listen or measures the usage of a channel during a given sensing period before making the decision whether to transmit on the channel or not during the data period of the data channel slot. If the channel or spectrum is used by another device the transmitter is configured to abstain from transmitting or select a different channel. This way the transmission does not interfere with other transmissions on the same channel. The above procedure may be called a LBT procedure.

In step 204, the transceiver is controlled to communicate on common and dedicated control channels on a shared spectrum using control channel slots, each control channel slot being associated with a downlink data channel slot and comprising a downlink part and an uplink part, wherein the uplink part occurs at the same time as the sensing period. In an embodiment, each control channel slot is associated with a data channel slot. The uplink part of the control channel slot can provide fixed feedback delay for downlink transmission (similar to LTE FDD) even in very downlink oriented downlink/uplink ratio in data transmission opportunities.

The process ends in step 206.

Figure 2B is a flowchart illustrating an embodiment of the invention. In an embodiment, the example relates to the operation of a base station or an eNodeB. The embodiment starts at step 210.

In step 212, a transceiver is controlled to communicate on shared data channels using a downlink data channel slot by sensing traffic of the data channel during a sensing period of the data channel slot and making a decision whether to transmit or not during a data period of the data channel slot on the basis of the sensing.

In step 214, the transceiver is controlled to communicate on common and dedicated control channels on a shared spectrum using control channel slots, each control channel slot being associated with a downlink data channel slot and comprising a downlink part and an uplink part, wherein the uplink part occurs at the same time as the sensing period.

The process ends in step 216. Figure 3 is a flowchart illustrating an example of the operation of a communication environment. The embodiment starts at step 300.

In step 302, a transceiver is controlled to detect and identify WLAN channels on given shared spectrum. The shared spectrum may be the ISM band on 2.4 or 5 GHz, for example. In an embodiment, downlink and uplink control channels are transmitted using frequency hopping (continuously in time domain) between the identified WLAN channels. Shared data channels for both downlink and uplink could 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 control 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 identified WLAN channels. Thus, the frequencies used in the transmission frequency blocks are hopping 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 defined by a base station or eNodeB or another network element of a communication system. When a UE is switched on it searches for control channel transmissions of an eNodeB. When the UE finds a control channel transmitted by an eNodeB it can obtain information of the hopping pattern from the eNodeB.

For example in 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 find resource at least for 15 non-overlapping frequency resources for the hopping control channel design. In addition, using the pair-wise hopping for the control channels and having hopping frequency of 1 ms (1 sub frame with two slots) allows a slot based hopping for Physical Uplink Control Channel (PUCCH) similar to current LTE based systems.

As mentioned above, in contrast to current LTE systems synchronization signals are not transmitted among the symbols of PDSCH, but in the control channel region utilizing the pair-wise hopping. In an embodiment, the hopping pattern and deployment of synchronization signals is designed so that the receiver (such as a UE) requiring the synchronization signals would not need to use the whole bandwidth of the ISM band to detect the synchronization signals in initial search phase of the LTE eNodeB on a ISM band. One option is to keep synchronization signals always in one region of the ISM band. The region may be the largest frequency region not used by the WLAN of 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 5 ms on certain resource region (the largest frequency region not used by the WLAN). E.g. when channels 1, 6 and 1 1 are used by a WLAN system, such 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 spectrum is used by another device the transmitter is configured to abstain from transmitting or select a different channel. 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. In the figure time runs from top to bottom. The spectrum comprises frequency resources 400 for data channels (i.e. data resources) and frequency resources 402 for control channels (i.e. control resources). The figure is not drawn to scale and is for illustrative purposes only. In an embodiment, common and dedicated control channels are mapped to two frequency blocks and the transmission of the frequency blocks utilizes pair-wise frequency hopping on a shared spectrum. More than one non-overlapping frequency resource may be utilised when transmitting in the two frequency blocks. For simplicity, Figure 4A illustrates the spectrum as one continuous block. Thus, the hopping pattern shown in Figure 4A is for illustrative purposes only.

Figure 4A shows four successive transmission time intervals (TTI) 404, 406, 408, 410. The TTIs may be slots, frames or sub frames, for example. In an embodiment, each TTI comprises a data channel slot and control transmission as control channel slot associated with the respective data channel block. The control channel slot comprises two frequency blocks. In LTE based systems the blocks may be three PRBs wide each.

In this example, the TTIs 404, 406 and 408 comprise downlink data channel slots and TTI 410 an uplink data channel slot. Thus, in the data channel slot of TTIs 404, 406 and 408 a base station or eNodeB may transmit to one or more UEs and in the data channel slot of TTI 410 one or more UEs may transmit to the base station(s). Each data channel slot comprises a sensing period 412A, 414A, 416A, 418A and a data period 412B, 414B, 416B, 418B. During the sensing period a transmitter which intends to transmit on the following data period is configured to sense traffic of the data channel and make a decision whether to transmit or not during a data period of the data channel slot on the basis of the sensing.

In case of the uplink TTI 410, the available frequency resource may be divided between more than one UE. Each UE may sense only the frequency resource given to the UE.

In an embodiment, control channel slots 420 comprise a downlink part 422 and an uplink part 424. Thus, in each given control channel slot 420 the base station or eNodeB may be configured to transmit on the downlink part 422 and UEs in the uplink part 424.

In an embodiment, the uplink part 424 of a control channel slot 420 is in the end of the control channel slot and the transmission of the control channel slot 420 starts at the same time as the data period 412B of the associated downlink data channel slot. Therefore, the uplink part 424 of the control channel slot 420 occurs at the same time as the sensing period 414A of the next data channel slot. Thus the timing of control channel slot is delayed by the length of uplink part compared to the slot timing of the downlink data channel slot.

In an embodiment, the uplink part of a control channel slot is in the beginning of the control channel slot. Figure 4B illustrates this embodiment. Figure 4B shows a TTI 426 comprising a data channel slot with a sensing period 428A and a data period 428B. The control channel slot 430 comprises an uplink part 432 and a downlink part 434 where the uplink part occurs at the time as the sensing period 428A.

As Figure 4A illustrates, there may be different control channels configurations, 420, 436, 438. Figures 5A, 5B and 5C illustrate examples of different configurations. In Figure 5A, the configuration comprises in the downlink part PCFICH, PDCCH, PHICH, PBCH, Primary Synchronization Signal (PSS) and Secondary Synchronization Signal (SSS). The uplink part comprises shortened PUCCH and shortened Random Access Channel (RACH). The downlink control channels are used by a base station for downlink scheduling commands, HARQ acknowledgements and uplink data transmission opportunity scheduling commands, for example.

Base station or eNodeB is configured to schedule uplink data transmission opportunities of the UEs regarding the uplink data channel slot of TTI 410 in the control channel slots 420. The UEs assigned the transmission opportunity need to sense the medium in the sensing period 418A and make a decision whether to transmit or not on the data period 418B of the scheduled resources. Furthermore, these UEs need to omit the uplink control channel transmission 450, 452 of the previous TTI 408 due to sensing requirement at the same time. The UEs that needed to omit their feedback transmission linked to certain previous downlink transmission shall then multiplex feedback for two downlink timeslots (depends on previous downlink transmissions to that specific UE into the PUCCH of the timeslot of uplink transmission opportunity or into scheduled PUSCH resources if UE decides to use those resources after sensing operation.

The transmission period of PSS, SSS and PBCH may be much higher than PCFICH, PDCCH and PHICH in practice as illustrated in Figure 4A. The synchronization signals are used by UEs searching for base stations to synchronize with a base station. After synchronization, UEs may obtain information regarding the base station from PBCH which is transmitted in the same downlink sub frame just before PSS and SSS transmissions to allow fast broadcast information detection after initial synchronization. The UEs are configured to buffer the control channel data so the PBCH data may be obtained from the buffer after obtaining synchronization.

The UEs which are already connected to a base station need not listen to PSS or SSS. Thus, a guard period is not needed between downlink and uplink parts.

Figure 5B illustrates an example 436 where downlink part 440 does not comprise synchronization signals and broadcast channel. In this example, a guard period 444 is required between the downlink part 440 and the uplink part 442.

Figure 5C illustrates an example 438 of control transmission occurring at the same time as the uplink data channel slot. The control transmission comprises PUCCH and RACH which may be longer that in the other configurations.

Figures 6 A and 6B are flowcharts illustrating embodiments of the invention especially from the base station or eNodeB point of view. Figure 6A illustrates an example of the operation of a base station eNodeB in case of a TTI comprising a downlink transmission opportunity, i.e. TTIs 404, 406 or 408 of Figure 4A.

The process starts at step 600.

In step 602, the eNodeB performs data sensing during sensing period 412 and at the same time receives control channel transmission from UEs on the uplink part of the control channel slot associated with the previous TTI.

In step 604, the eNodeB decides on scheduling downlink data transmission on the basis of the sensing. If downlink data is to be transmitted, the eNodeB is configured to prepare downlink control channels in step 606 by indicating by given Radio Network Temporary Identifier (RNTI) on PDCCH common field that downlink opportunity is used in this time slot, select users to be scheduled and generate corresponding PDCCH. The process continues in steps 608 and 614.

In step 608, the eNodeB is configured to prepare downlink data channels for the selected users.

In step 610, the downlink data is transmitted in the data period 412B.

If the eNodeB determines in step 604 that downlink data is not to be transmitted, the process continues in step 612 by preparing downlink control channels by indicating in PCFICH that downlink opportunity is not used.

In step 614, the eNodeB determines if there is an uplink transmission slot becoming after a given delay t_uirj_ei_aY. As uplink data transmissions are scheduled by the eNodeB the scheduling command must be transmitted to the UEs a given time before the uplink transmission opportunity. In LYTE based systems the given time is denoted as t_ui_Dei_ay.

If there is an uplink transmission slot required, the eNodeB selects UEs to be scheduled and adds an uplink information part to PDCCH in step 616.

If there is no uplink transmission required the process continues in step 618 to determine if there were uplink transmissions from UEs in a time slot which was a given delay t_ackN_ackrj_ei_ay before the present time slot.

If so, the eNodeB generates HARQ ACKL/NACK on PHICH for these users in step 620.

If not the eNodeB transmits control channels in step 622 on the downlink part of control channel slot.

The process ends in step 624.

Figure 6B illustrates an example of the operation of a base station eNodeB in case of a TTI comprising an uplink transmission opportunity, i.e. TTI 410 of Figure 4A.

The process starts at step 630.

In step 632, the eNodeB is configured to receive transmissions 450, 452 from UEs on uplink part of control channel associated with the previous data slot during the sensing period 418 A. The process continues simultaneously in steps 634 and 636.

In step 634, the eNodeB receives data transmissions from UEs on data part 418B of the TTI 410. In step 636, the eNodeB receives transmissions 438, 454 from UEs on control part of the resources.

The process ends in step 638.

Figure 7 is a flowchart illustrating an embodiment of the invention especially from the UE point of view.

The process starts at step 700.

In step 702, UE determines is the current TTI is an uplink or downlink transmission TTI for example 406 or 410 in Figure 4A. If it is an uplink transmission TTI the process continues in step 714.

If it an uplink transmission TTI the process continues in step 704. In step 704 (i.e TTI 406) , the UE determines whether there is a need to transmit HARQ ACK/NACK of a previous downlink transmission during the uplink part of a control slot of previous TTI during the sensing period of the present TTI.

If so, PUCCH is transmitted on uplink part of control slots 424, 456 in step

706.

If not, the process continues in step 708 by determining if there is a need to transmit PUCCH (e.g. implicit mapping from early downlink transmission) during the uplink part of a control slot of the present TTI.

If so, PUCCH is transmitted on uplink part of control slot 458, 460 in step

710.

If it is a downlink transmission TTI was detected in step 702 the process continues in step 714 by sensing the resources allocated for the UE.

In step 716, the UE determines on the basis of sensing whether to transmit or not. If not, process continues in step 708.

In step 718, the UE prepares uplink transmission of data and control information.

In step 720, the UE transmits data on the data period.

The process ends in step 712.

Figure 8 illustrates a simplified example of an apparatus for applying embodiments of the invention. In some embodiments, the apparatus may be an eNodeB or UE of a communications system. The apparatus may also be interpreted as a circuitry implementing the required functionality within an eNodeB or UE of a communications system.

It should be understood that the apparatus is depicted herein as an example illustrating some embodiments. It is 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 800 configured to control at least part of the operation of the apparatus.

The apparatus comprises a memory 802 for storing data. Furthermore the memory stores software 804 executable by the control circuitry 800. The memory in this example is integrated in the control circuitry.

The apparatus comprises a transceiver 806. The transceiver is operationally connected to the control circuitry 800. It may be connected to an antenna arrangement (not shown).

The software 804 comprises a computer program comprising program code means adapted to cause the control circuitry 800 of the apparatus to control the transceiver 806.

The apparatus may further comprise interface circuitry 808 configured to connect 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 may provide a wired or wireless connection to the communication network. The apparatus may be in connection with core network elements, eNodeB 's, HNBs and with other respective apparatuses of communication systems.

The apparatus may further comprise user interface 810 operationally connected to the control circuitry 800. The user interface may comprise a display, a keyboard or keypad, a microphone and a speaker, for example. This applies especially if the apparatus is user equipment or respective network element.

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 simultaneously or in an order differing from the given one. Other functions can also be executed 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 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 programming language, such as a machine language, or an assembler. The electronic digital 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 following: (a) hardware-only circuit implementations, such as implementations in only analog 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 application. 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 'circuitry' 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 apparatus, 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 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 implementation, 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.

In an embodiment, the apparatus comprises means for controlling the communication of a transceiver on shared data channels using a data channel slot comprising a sensing period and a data period and means for controlling a transceiver to communicate on common and dedicated control channels on a shared spectrum using control channel slots, each control channel slot comprising a downlink part and an uplink part, wherein the uplink part occurs at the same time as the sensing period of a data channel slot.

It will be obvious to a person skilled in the art that, as technology advances, 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 claim.

Claims

1. An apparatus operable in a communication system to:

control the communication of a transceiver on shared data channels using a data channel slot comprising a sensing period and a data period, and

control a transceiver to communicate on common and dedicated control channels on a shared spectrum using control channel slots, each comprising a downlink part and an uplink part,

wherein, the uplink part occurs at the same time as the sensing period of a data channel slot.

2. The apparatus of claim 1, operable to

control the transmission of a transceiver on shared data channels using a downlink data channel slot by sensing traffic of the data channel during a sensing period of the data channel slot and to decide whether to transmit or not during a data period of the data channel slot on the basis of the sensing; and

control a transceiver to communicate on common and dedicated control channels on a shared spectrum using control channel slots, each control channel slot being associated with a downlink data channel slot and comprising a downlink part and an uplink part, wherein the uplink part occurs at the same time as the sensing period.

3. The apparatus of claim 2, operable to control the transceiver to transmit in predetermined control channel slots a broadcast control channel prior synchronization symbols in the end of the downlink part of the control channel slot.

4. The apparatus of claim 3, wherein the control channel slots comprising a downlink part and an uplink part except the predetermined control channel slots comprise a transition period between the downlink part and the uplink.

5. The apparatus of claim 2, wherein the downlink part of the control channel slots comprise downlink scheduling commands and uplink data transmission opportunity scheduling commands.

6. The apparatus of claim 1 , wherein the uplink part of a control channel slot is in the beginning of the control channel slot.

7. The apparatus of claim 1 , wherein the uplink part of a control channel slot is in the end of the control channel slot and the transmission of the control channel slot starts at the same time as the data period of the associated downlink data channel slot and the uplink part of the control channel slot occurs at the same time as the sensing period of the next data channel slot.

8. The apparatus of claim 1 , operable to control the transceiver to map common and dedicated control channels on two frequency blocks wherein the transmission of the frequency blocks utilize pair-wise frequency hopping on a shared spectrum.

9. The apparatus of claim 8, operable to control the transceiver to utilise more than one non-overlapping frequency resource when transmitting the two frequency blocks utilising pair-wise frequency hopping.

10. The apparatus of claim 1, operable to

control a transceiver to receive downlink control channels during the downlink part of the control channel slot and transmit uplink control channels using the uplink part of the control channel slot;

control a transceiver to receive a scheduling command from a base station for uplink transmission opportunity using a given uplink data channel slot; and

control the communication of a transceiver on shared data channels using the given uplink data channel slot by sensing traffic of the data channel during a sensing period of the data channel slot and making a decision whether to transmit or not during a data period of the data channel slot on the basis of the sensing.

11. The apparatus of claim 1 , operable to refrain from transmitting on the uplink part of control channel slots occurring at the same time as uplink data channel slot.

12. The apparatus of claim 10, operable to transmit control channel slots comprising only an uplink part when transmitting an uplink data channel slot.

13. A method in a communication system, comprising:

controlling the communication of a transceiver on shared data channels using a data channel slot comprising a sensing period and a data period; and controlling a transceiver to communicate on common and dedicated control channels on a shared spectrum using control channel slots, each control channel slot comprising a downlink part and an uplink part, wherein the uplink part occurs at the same time as the sensing period of a data channel slot.

14. The method of claim 13, further comprising:

controlling the transmission of a transceiver on shared data channels using a downlink data channel slot by sensing traffic of the data channel during a sensing period of the data channel slot and making a decision whether to transmit or not during a data period of the data channel slot on the basis of the sensing; and

controlling a transceiver to communicate on common and dedicated control channels on a shared spectrum using control channel slots, each control channel slot being associated with a downlink data channel slot and comprising a downlink part and an uplink part, wherein the uplink part occurs at the same time as the sensing period.

15. The method of claim 14, further comprising: controlling the transceiver to transmit in predetermined control channel slots a broadcast control channel prior synchronization symbols in the end of the downlink part of the control channel slot.

16. The method of claim 14, wherein the control channel slots comprising a downlink part and an uplink part except the predetermined control channel slots comprise a transition period between the downlink part and the uplink.

17. The method of claim 14, wherein the uplink part of a control channel slot is in the beginning of the control channel slot.

18. The method of claim 14, wherein the uplink part of a control channel slot is in the end of the control channel slot and the transmission of the control channel slot starts at the same time as the data period of the associated downlink data channel slot and the uplink part of the control channel slot occurs at the same time as the sensing period of the next data channel slot.

19. The method of claim 13, further comprising:

controlling a transceiver to receive downlink control channels during the downlink part of the control channel slot and transmit uplink control channels using the uplink part of the control channel slot; controlling a transceiver to receive a scheduling command from a base station for uplink transmission opportunity using a given uplink data channel slot; and controlling the communication of a transceiver on shared data channels using the given uplink data channel slot by sensing traffic of the data channel during a sensing period of the data channel slot and making a decision whether to transmit or not during a data period of the data channel slot on the basis of the sensing.

20. The method of claim 19, further comprising: refraining from transmitting on the uplink part of control channel slots occurring at the same time as uplink data channel slot.

21. The method of claim 20, further comprising: transmitting control channel slots comprising only an uplink part when transmitting an uplink data channel slot.

22. A computer program comprising program code means adapted to perform the steps of any of claims 13 to 21 when the program is run on a computer.

23. A transceiver arrangement comprising an apparatus according to any one of claims 1 to 12.