WO2013097144A1

WO2013097144A1 - An apparatus and a method for frequency band switching in a mobile communication system

Info

Publication number: WO2013097144A1
Application number: PCT/CN2011/084916
Authority: WO
Inventors: Wei Bai; Haiming Wang; Chunyan Gao; Tao Peng
Original assignee: Renesas Mobile Corporation
Priority date: 2011-12-29
Filing date: 2011-12-29
Publication date: 2013-07-04

Abstract

The invention concerns a method and an apparatus for device-to-device communication route establishment within a mobile communication system. In the method a mobile node receives an indication of a first radio resource on a first frequency band from a base station. The mobile node determines that a second radio resource on a second frequency band is available for transmitting data to a remote node. The mobile node transmits data to the remote node using the second radio resource. The mobile node determines that an allocation time for the second radio resource has elapsed. Thereupon, in response to a failure to obtain a radio resource on the second frequency band, the mobile node transmits data to the remote node using the first radio resource.

Description

AN APPARATUS AND A METHOD FOR FREQUENCY BAND SWITCHING IN A MOBILE COMMUNICATION SYSTEM

BACKGROUND OF THE INVENTION

Field of the invention:

The invention relates to mobile communica^¬ tions networks, device-to-device communication between end-user devices, and an apparatus and a method for frequency band switching in a mobile communication system .

Description of the Related Art:

The field of data communications has been in turmoil during the recent years. New technologies are being introduced while old technologies are being dis^¬ mantled. Particularly, the data rates in wireless mo^¬ bile communication systems have been increasing in the recent years rapidly. Long-Term Evolution (LTE) standardized by the 3G Partnership Project (3GPP) repre^¬ sents a significant leap forward in wireless mobile communication systems. One of the main objectives of the LTE is the providing of downlink data rates of at least 100 Mbps and uplink date rates of at least 50 Mbps . In order to be able to increase the data rates it should be possible to deploy new frequency bands into usage. One option of increasing the data rates is via the unloading of traffic from licensed frequency bands agreed for LTE. A significant amount of traffic may be unloaded from the licensed frequency bands if the traffic actually destined to a device that may be accessed with direct Device-to-Device (D2D) communica^¬ tions is implemented in the form of unlicensed band device-to-device traffic. Device-to-device communica^¬ tions also enable the introduction of proximity based services and applications. The services and applica^¬ tions are based on the awareness of two devices are close to each other. The awareness of proximity may generate a demand to exchange data between the devices Certain amount of traffic currently served by licensed bands is further inherently replaceable with unli^¬ censed frequency band device-to-device traffic based on the proximity of devices within a single company or a single flat.

The possibility for device-to-device communi^¬ cation between end-user terminals has been discussed in LTE standardization. The use of device-to-device communication provides certain advantages. Firstly, it allows the saving of uplink and downlink radio re^¬ sources, for example, Orthogonal Frequency Multiple Access (OFDMA) or Single-Carrier Frequency Domain Multiple Access (SC-FDMA) resource blocks to be freed and thereby increases the overall capacity available for users that cannot harness device-to-device communica^¬ tion for their own purposes, for example, if they are downloading files from a distant server. Secondly, de^¬ vice-to-device communication may take place within frequency bands having a transmission power upper limit such as TV channels adjacent to an operational TV channel in TV White Spaces (TVWS) . Thirdly, device- to-device communication may be used to increase the coverage area of a base station cell to areas where it would otherwise not reach, for example, to tunnels, caves and buildings not equipped with base stations. This is achieved by the use of chains of end-user de^¬ vices that end to a device which is actually within the coverage area of a base station cell. Fourthly, the use of the use of device-to-device communication requires less transmission power compared to normal uplink transmission and that in turn reduces battery drainage. Fifthly, in some cases device-to-device com^¬ munication may provide better radio channel quality, which in turn leads to improved Quality of Service (QoS) for users. When deploying device-to-device communication on an unlicensed band, one of the most critical chal^¬ lenges is the unlicensed band' s inherent share prop^¬ erty, which means that multiple systems may use the same band without knowledge on each other. For example on the Industrial, Scientific and Medical (ISM) bands, there may be WiFi™ systems (IEEE 802.1 la/b/g/n/ac) , as well as Bluetooth™, ZigBee™, wireless USB, cordless phone and Microwave. As for white spaces such as TV White Spaces, there may be some other systems also trying to use those spectrums concurrently.

If the unlicensed band is very busy, for ex^¬ ample, occupied by traffic from some other systems, it will be hard to ensure sufficient QoS for the traffic on the unlicensed band, which is served by D2D direct communication, because of the interference which may not be expected beforehand. Any LTE D2D communications using the unlicensed band will also break the fairness

It would be beneficial to be able to coordi^¬ nate the use of the unlicensed band in order to enable a contiguous transmission between D2D devices and pro^¬ vide a good user experience without breaking the fair^¬ ness. It would be beneficial if the D2D devices could be able to use unlicensed band as part of their commu^¬ nications normally deploying the licensed band, for example, so that a separate communication session such as, for example, a TCP/IP connection or a Session Initiation Protocol (SIP) session does not have to be es^¬ tablished each time unlicensed band is going to be used .

SUMMARY OF THE INVENTION :

According to an aspect of the invention, the invention is a method, comprising: receiving, in a mobile node, an indication of a first radio resource on a first frequency band; determining, in the mobile node, that a second radio resource on a second fre^¬ quency band is available for transmitting data to a remote node; transmitting, by the mobile node, data to the remote node using the second radio resource; de^¬ termining, by the mobile node, that an allocation time for the second radio resource has elapsed; determining, in the mobile node, a failure to find an available ra^¬ dio resource on the second frequency band; and trans^¬ mitting, by the mobile node, data to the remote node using the first radio resource, in response to the de^¬ termining of the failure to find the available radio resource on the second frequency band.

According to a further aspect of the invention, the invention is a method, comprising: allocating a first radio resource on a first frequency band to a first mobile node; transmitting, from a base sta^¬ tion, an indication of the first radio resource; de^¬ termining, in the base station, that a second radio resource on a second frequency band is reserved for a first mobile node; allocating the first radio resource, by the base station, to a second mobile node temporar^¬ ily; determining, in the base station, that no radio resource on the second frequency band is reserved for the first mobile node; and maintaining the first radio resource exclusively allocated to the first mobile node in response to the determining that no radio re^¬ source on the second frequency band is reserved for the first mobile node.

According to a further aspect of the invention, the invention is an apparatus comprising: at least one processor configured to receive an indica^¬ tion of a first radio resource on a first frequency band, to determine that a second radio resource on a second frequency band is available for transmitting data to a remote node, to transmit data to the remote node using the second radio resource, to determine that an allocation time for the second radio resource has elapsed, to determine a failure to find an avail^¬ able radio resource on the second frequency band, and to transmit data to the remote node using the first radio resource, in response to the determining of the failure to find the available radio resource on the second frequency band.

According to a further aspect of the invention, the invention is a mobile node comprising the apparatus .

According to a further aspect of the invention, the invention is an apparatus comprising: at least one processor configured to allocate a first ra^¬ dio resource on a first frequency band to a first mo^¬ bile node, to transmit an indication of the first ra^¬ dio resource to the first mobile node, to determine that a second radio resource on a second frequency band is reserved for a first mobile node, to allocate the first radio resource to a second mobile node tem^¬ porarily, to determine that no radio resource on the second frequency band is reserved for the first mobile node, and to maintain the first radio resource exclu^¬ sively allocated to the first mobile node in response to the determining that no radio resource on the sec^¬ ond frequency band is reserved for the first mobile node .

According to a further aspect of the invention, the invention is a base station comprising the apparatus .

According to a further aspect of the invention, the invention is a system comprising the mobile node and the base station.

According to a further aspect of the invention, the invention is an apparatus comprising: means for receiving an indication of a first radio resource on a first frequency band; means for determining that a second radio resource on a second frequency band is available for transmitting data to a remote node; means for transmitting data to the remote node using the second radio resource; means for determining that an allocation time for the second radio resource has elapsed; means for determining a failure to find an available radio resource on the second frequency band; and means for transmitting, by the mobile node, data to the remote node using the first radio resource, in response to the determining of the failure to find the available radio resource on the second frequency band.

According to a further aspect of the invention, the invention is an apparatus comprising: means for allocating a first radio resource on a first fre^¬ quency band to a first mobile node; means for trans^¬ mitting an indication of the first radio resource; means for determining that a second radio resource on a second frequency band is reserved for a first mobile node; means for allocating the first radio resource to a second mobile node temporarily; means for determining, in the base station, that no radio resource on the second frequency band is reserved for the first mobile node; and means for maintaining the first radio resource exclusively allocated to the first mobile node in response to the determining that no radio re^¬ source on the second frequency band is reserved for the first mobile node.

According to a further aspect of the invention, the invention is a computer program comprising code adapted to cause the following when executed on a data-processing system: receiving, in a mobile node, an indication of a first radio resource on a first frequency band; determining, in the mobile node, that a second radio resource on a second frequency band is available for transmitting data to a remote node; transmitting, by the mobile node, data to the remote node using the second radio resource; determining, by the mobile node, that an allocation time for the sec^¬ ond radio resource has elapsed; determining, in the mobile node, a failure to find an available radio re^¬ source on the second frequency band; and transmitting, by the mobile node, data to the remote node using the first radio resource, in response to the determining of the failure to find the available radio resource on the second frequency band.

According to a further aspect of the invention, the invention is a computer program product comprising the computer program.

According to a further aspect of the invention, the invention is a computer program comprising code adapted to cause the following when executed on a data-processing system: allocating a first radio resource on a first frequency band to a first mobile node; transmitting, from a base station, an indication of the first radio resource; determining, in the base station, that a second radio resource on a second fre^¬ quency band is reserved for a first mobile node; allo^¬ cating the first radio resource, by the base station, to a second mobile node temporarily; determining, in the base station, that no radio resource on the second frequency band is reserved for the first mobile node; and maintaining the first radio resource exclusively allocated to the first mobile node in response to the determining that no radio resource on the second fre^¬ quency band is reserved for the first mobile node.

In one embodiment of the invention, the radio resource comprises at least one single carrier fre^¬ quency division multiple access resource element which may be on adjacent subcarriers or on adjacent symbols. The resource elements may be seen as elements in a re^¬ source grid.

In one embodiment of the invention, the radio resource comprises at least one orthogonal frequency division multiple access resource element which may be on adjacent subcarriers or on adjacent symbols. The resource elements may be seen as elements in a re^¬ source grid.

In one embodiment of the invention, the radio resource comprises at least one orthogonal frequency division multiplexing resource element which may be on adjacent subcarriers or on adjacent symbols.

In one embodiment of the invention, the radio resource comprises at least one frequency range.

In one embodiment of the invention, a fre^¬ quency band is a frequency range.

In one embodiment of the invention, the radio resource comprises at least one time interval within at least one frequency range.

In one embodiment of the invention, the radio resource may comprise at least one of a channel, a frequency band, a frequency range, a subcarrier, a carrier, a timeslot and a slot.

In one embodiment of the invention, by an available radio resource is meant a radio resource which has a measured noise level below a predefined threshold value. The noise level may be on a level that permits the use of the radio resource for device- to-device communication with sufficient radio communication quality. The noise may comprise at least one of background noise, noise from transmissions from other radio systems, Gaussian noise, noise from transmis^¬ sions from individual devices not comprised in the set comprising the mobile node, the remote node or the base station.

In one embodiment of the invention, by an available radio resource is meant a radio resource which has a measured signal-to-noise ratio above a predefined threshold value. The signal-to-noise ratio may be measured, in the mobile node or in the base station, with respect to at least one reference signal transmitted by the base station or the mobile node during radio resource or spectrum scanning. The scanning may be performed according to a known schedule of transmitting the at least one reference signal by the base station or the mobile node depending on the performer of the spectrum or radio resource scanning.

In one embodiment of the invention, the indi^¬ cation of the first radio resource on the first fre^¬ quency band may be received from a base station.

In one embodiment of the invention, in re^¬ sponse to a failure to obtain a radio resource on the second frequency band, the mobile node performs the step of transmitting the data to the remote node using the first radio resource. The failure may be due to spectrum sensing in the base station or the mobile node. In case the spectrum sensing is performed by the base station, the failure may be reported to the mo^¬ bile node from the base station.

In one embodiment of the invention, the base station determines that no radio resource on the sec^¬ ond frequency band is reserved for the first mobile node based on a report from the mobile node indicating a failure to find an available radio resource on the second frequency band. In response, the base station maintains the first radio resource exclusively allo^¬ cated to the first mobile node.

In one embodiment of the invention, the de^¬ termining, by the mobile node, that the allocation time for the second radio resource has elapsed is based on a request from the base station to perform spectrum sensing by the mobile node of at least one of the second radio resource and the second frequency band to obtain a radio resource on the second fre- quency band. The mobile node may send a response to the request to the base station indicating whether the obtaining of a radio resource was successful. If the obtaining was not indicated to be successful the base station may determine that no radio resource on the second frequency band is reserved for the first mobile node .

In one embodiment of the invention, the de^¬ termining, by the mobile node, that the allocation time for the second radio resource has elapsed is based on a timer or a clock within the mobile node. The mobile node also comprises a clock in this embodi^¬ ment .

In one embodiment of the invention, the mo^¬ bile node may receive a request from the base station to perform spectrum sensing. The spectrum sensing is performed for at least one of the second radio re^¬ source and the second frequency band to obtain a radio resource on the second frequency band. The mobile node may send a response to the request to the base station indicating whether the obtaining of a radio resource was successful. If the obtaining was not indicated to be successful the base station may determine that no radio resource on the second frequency band is re^¬ served for the first mobile node.

In one embodiment of the invention, the base station determines that no radio resource on the sec^¬ ond frequency band is reserved for the first mobile node based on a failure to find an available radio re^¬ source on the second frequency band by the base sta^¬ tion when the base station has performed spectrum sensing of at least one of the second radio resource and the second frequency band.

In one embodiment of the invention, the mo^¬ bile node, at the time determining that the allocation time for the second radio resource has elapsed, deter^¬ mines that it is time to perform spectrum sensing in the second frequency band to find an available radio resource that may be used by the mobile node instead of the first radio resource on the first frequency band. If mobile node finds the available radio re^¬ source in the second frequency band, it indicates the finding of the available radio resource to the base station. The mobile node may also indicate the failure of finding an available radio resource, for example, the second radio resource or any other radio resource, in the second frequency band to the base station or the omission of an indication, within a timer interval, of finding an available radio resource in the second frequency band may be interpreted by the base station as such an indication of failure in finding an available radio resource in the second frequency band. In response to the report of the finding, the base sta^¬ tion may allocate the first radio resource on the first frequency band for other uses, such as, for other mobile nodes. In response to indication of fail^¬ ure to find an available radio resource on the second frequency band by the mobile node, the base station maintains the first radio resource allocated for the mobile node exclusive. Only after a report of later success in finding an available radio resource on the second frequency band from the mobile node, the base station may allocate the first radio resource for other mobile nodes temporarily or for other use.

In one embodiment of the invention, by equivalent radio resources are meant radio resources with at least one respective quality of service pa^¬ rameter that differs only within a predefined limit between the radio resources. In this case a quality of service parameter may be a radio quality parameter. The parameter that differs between two radio resources within a predefined limit may be, for example, throughput or bit error rate. In one embodiment of the invention, the step of determining the failure to find the available radio resource on the second frequency band comprises re^¬ ceiving a message indicating the failure to find the available radio resource on the second frequency band from a base station. The radio resource that the base station fails to find may be the second radio resource or any other radio resource on the second frequency band. The radio resource to be found may be a radio resource equivalent to the first radio resource.

In one embodiment of the invention, the step of determining, in the mobile node, a failure to find an available radio resource on the second frequency band is referred to as a step of determining a failure to find an available radio resource on the second fre^¬ quency band.

In one embodiment of the invention, the step of determining a failure to find an available radio resource on the second frequency band comprises a failure to find the second radio resource as available.

In one embodiment of the invention, the step of determining the failure to find the available radio resource on the second frequency band comprises: per^¬ forming spectrum sensing by the mobile node of at least one of the second radio resource and the second frequency band; and determining, in response to the sensing, the failure to find the available radio re^¬ source. The available radio resource that the mobile node fails to find with spectrum sensing or radio re^¬ source sensing may be the second radio resource or any other radio resource on the second frequency band.

In one embodiment of the invention, the method further comprises receiving, in the mobile node, an indication of an index corresponding to the second radio resource on a second frequency band. The indica^¬ tion may be received from a base station. In one embodiment of the invention, the step of determining that the second radio resource is available for transmitting data to a remote node com^¬ prises: receiving an assignment indicating the avail^¬ ability of the second radio resource. The assignment may be received from a base station.

In one embodiment of the invention, the method further comprises transmitting, from the mobile node, to a base station a report indicating successful determination of the second radio resource.

In one embodiment of the invention, the step of determining that a second radio resource is avail^¬ able for transmitting data to a remote node comprises: performing spectrum sensing by the mobile node of at least one of the second radio resource and the second frequency band; and determining, in response to the sensing, the availability of the second radio resource.

In one embodiment of the invention, the spec^¬ trum sensing comprises finding a radio resource in the spectrum due to the fact that it has a noise level that is below a predefined threshold level for an al^¬ lowed noise level. The noise may comprise both trans^¬ missions from other systems and background noise such as Gaussian noise.

In one embodiment of the invention, the method further comprises transmitting, by the mobile node, a report to a base station indicating release of the second radio resource.

In one embodiment of the invention, the first radio resource is comprised in a licensed frequency band and the second radio resource is comprised in an unlicensed frequency band.

In one embodiment of the invention, the method further comprises: determining a noise level on the second frequency band; determining whether noise level exceeds a predefined threshold; and entering an unlicensed radio band mode in the mobile node in re- sponse to the noise level exceeding the predefined threshold .

In one embodiment of the invention, the method further comprises switching off, in the unlicensed radio band mode, at least one wireless local area network circuit.

In one embodiment of the invention, the method further comprises determining a noise level on the second frequency band; determining whether the noise level exceeds a predefined threshold; and enter^¬ ing a licensed radio band mode in the mobile node in response to the noise level being below the predefined threshold .

In one embodiment of the invention, the step of determining that the second radio resource is available for transmitting data to a remote node fur^¬ ther comprises transmitting a wireless local area net^¬ work radio frame to the remote node.

In one embodiment of the invention, the method further comprises transmitting, from the base station, an indication of an index corresponding to the second radio resource on the second frequency band

In one embodiment of the invention, the step of determining that the second radio resource is re^¬ served for a first mobile node further comprises re^¬ ceiving an indication of the reservation from the first mobile node.

In one embodiment of the invention, the step of determining that the second radio resource is re^¬ served for a first mobile node further comprises allo^¬ cating the second radio resource for the first mobile node .

In one embodiment of the invention, the method further comprises: performing spectrum sensing of the second radio resource by the base station; and determining, in response to the sensing, the avail^¬ ability of the second radio resource. In one embodiment of the invention, the mo^¬ bile node comprises at least one of a handset, a chip^¬ set, a mobile device, a mobile phone, a wireless modem, and a mobile terminal.

In one embodiment of the invention, the appa^¬ ratus comprises at least one of a handset, a chipset, a mobile device, a mobile phone, a wireless modem, and a mobile terminal.

In one embodiment of the invention, the appa^¬ ratus or the mobile phone is configured to perform the method disclosed hereinbefore.

In one embodiment of the invention, the mo^¬ bile node comprises a Long-Term Evolution (LTE) User Equipment .

In one embodiment of the invention, the re^¬ mote node is a remote mobile node, for example an LTE User Equipment (UE) . The remote node may also be a desktop, a desk computer or a server.

In one embodiment of the invention, the re^¬ mote node is a mobile node, which may be referred to as a second mobile node.

In one embodiment of the invention, the sym^¬ bols are OFD A or Single Carrier Frequency Division Multiple Access (SC-FDMA) symbols.

In one embodiment of the invention, the at least one processor of the apparatus, for example, of the mobile node may be configured to perform the method steps disclosed hereinabove.

In one embodiment of the invention, the at least one processor of the apparatus, for example, of the base station may be configured to perform the method steps disclosed hereinabove.

In one embodiment of the invention, the base station is an apparatus comprising a number of base station receivers and/or transmitters and a base sta^¬ tion node. The base station node may be a base station server or a central unit.

In one embodiment of the invention, the base station comprises an Evolved UMTS Radio Access Network (E-UTRAN) node such as, for example, an Evolved NodeB. At least one processor in the base station node may be configured to perform the method steps disclosed here^¬ inabove. The transmission and reception may be performed by the at least one radio frequency circuit.

In one embodiment of the invention, the de^¬ vice-to-device communication may be a connection, for example, a transport layer connection, such as, for example, a TCP connection or a Stream Control Trans^¬ mission Protocol (SCTP) connection. The communication may also be a flow of individual packets, for example, a flow of UDP packets. The flow of UDP packets may represent, for example, a media component associated with a multimedia session. In one embodiment of the invention, the communication may be set-up or established on any protocol layer, for example, it may be established, for example, also on Point-To-Point Pro^¬ tocol (PPP) layer or on a logical link layer.

In one embodiment of the invention, the base station comprises an OFDMA radio network node or an SC-FDMA radio network node.

In one embodiment of the invention, the at least one Radio Frequency (RF) circuit in the mobile node may also be referred to as at least one circuit.

In one embodiment of the invention, the at least one Radio Frequency (RF) circuit in the base station node may also be referred to as at least one circuit .

In one embodiment of the invention, the mo^¬ bile node such as a User Equipment (UE) comprises a mobile station or generally a mobile terminal. In one embodiment of the invention a user of a mobile termi- nal is identified using a subscriber module, for exam^¬ ple, User Services Identity Module (USIM) or a Sub^¬ scriber Identity Module (SIM) . The combination of Mobile Equipment (ME) and a subscriber module may be re^¬ ferred to as a mobile subscriber. A mobile subscriber may be identified using an IMS I. An IP address may be allocated or associated with a mobile subscriber.

In one embodiment of the invention, the appa^¬ ratus is a mobile terminal, for example a, mobile handset .

In one embodiment of the invention, the method steps mentioned hereinbefore are performed by the apparatus or the mobile node.

In one embodiment of the invention, the appa^¬ ratus is a semiconductor circuit, a chip or a chipset.

In one embodiment of the invention, the base station node is configured to be used in a 4G system such as, for example, LTE Evolved Packet System (EPS) .

In one embodiment of the invention, a radio resource, for example, for the transmission or for the device-to-device transmission may be a particular channel, a given number of symbols on a given number of subcarriers, a given number of subcarriers within a symbol time, a number of resource elements, or a num^¬ ber of resource blocks. The radio resource location in terms of frequency and time may be indicated by the base station.

In one embodiment of the invention, a radio resource may comprise at least one of: at least one resource block, at least one resource element, at least one SC-FDMA resource block, at least one SC-FDMA resource element, at least one OFDMA or OFDM resource block, at least one OFDMA or OFDM resource element, at least one Long-Term Evolution resource block, at least one Long-Term Evolution resource element.

In one embodiment of the invention, the com^¬ puter program is stored on a computer readable medium. The computer readable medium may be, but is not lim^¬ ited to, a removable memory card, a removable memory module, a magnetic disk, an optical disk, a holo^¬ graphic memory or a magnetic tape. A removable memory module may be, for example, a USB memory stick, a PCMCIA card or a smart memory card.

In one embodiment of the invention, the com^¬ puter program product is stored on a computer readable medium. The computer readable medium may be, but is not limited to, a removable memory card, a removable memory module, a magnetic disk, an optical disk, a holographic memory or a magnetic tape. A removable memory module may be, for example, a USB memory stick, a PCMCIA card or a smart memory card.

The embodiments of the invention described hereinbefore may be used in any combination with each other. Several of the embodiments may be combined to^¬ gether to form a further embodiment of the invention. A method, a base station, an apparatus, a computer program or a computer program product to which the invention is related may comprise at least one of the embodiments of the invention described hereinbefore.

It is to be understood that any of the above embodiments or modifications can be applied singly or in combination to the respective aspects to which they refer, unless they are explicitly stated as excluding alternatives .

The benefits of the invention are related to enhanced data transmission capacity in a mobile commu^¬ nication system by the virtue of increased use of de^¬ vice-to-device communication in place of uplink and downlink communication with a base station. The device-to-device communication may employ an unlicensed band instead of a licensed band. BRIEF DESCRIPTION OF THE DRAWINGS:

The accompanying drawings, which are included to provide a further understanding of the invention and constitute a part of this specification, illus^¬ trate embodiments of the invention and together with the description help to explain the principles of the invention. In the drawings:

Fig. 1A illustrates an alternate use of two frequency bands by two mobile nodes in their mutual device-to-device communication in one embodiment of the invention;

Fig. IB illustrates an alternate use of two frequency bands by two mobile nodes in their mutual device-to-device communication in one embodiment of the invention where the mobile node may perform spec^¬ trum scanning to obtain a radio resource in a second frequency band;

Fig. 2A is a first part of a flow chart il^¬ lustrating a method for frequency band switching in a base station in one embodiment of the invention;

Fig. 2B is a second part of a flow chart il^¬ lustrating a method for frequency band switching in a base station in one embodiment of the invention;

Fig. 3A is a first part of a flow chart il^¬ lustrating a method for frequency band switching in a mobile node in one embodiment of the invention;

Fig. 3B is a second part of a flow chart il^¬ lustrating a method for frequency band switching in a mobile node in one embodiment of the invention;

Fig. 4 is a flow chart illustrating a method for radio system selection in a mobile node in one embodiment of the invention;

Fig. 5 illustrates an apparatus in one em^¬ bodiment of the invention; and

Fig. 6 illustrates an apparatus in one em^¬ bodiment of the invention. DETAILED DESCRIPTION OF THE EMBODIMENTS :

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

Figure 1 illustrates an alternate use of two frequency bands by two mobile nodes in their mutual device-to-device communication in one embodiment of the invention.

In Figure 1 there is illustrated time and frequency domains used by a base station 114 and a first mobile node 110 and second mobile node 112. In the frequency domain there are two frequency bands, namely, a licensed frequency band and an unlicensed frequency band. The unlicensed frequency band com^¬ prises a number of radio resources which have a corre^¬ sponding index (II, 12, 13 and IN) assigned to them. The radio resources may comprise, for example, at least one of a number of Long-Term Evolution (LTE) subcarriers and a number of symbols, which may be, for example, SC-FDMA or OFDMA symbols. The radio resources may comprise LTE resource blocks or LTE resource ele^¬ ments. The indexed radio resources may comprise not only sub-carriers or frequencies, but also separate time periods. The time periods may be defined in a ra^¬ dio frame and/or radio subframe structure. The start^¬ ing point in Figure 1 is that mobile node 110 has de^¬ termined a need to perform communication with mobile node 112. The need may be determined locally at mobile node 110 or at base station 114, for example, based on routing information provided from mobile node 110, as part of a communication establishment request. Mobile node 110 may also send a request for a radio resource. The request may specify that the radio resource is for device-to-device communication. At time Tl base station 114 allocates a li^¬ censed band radio resource for mobile node 110. The licensed band radio resource will be used for device- to-device communication between mobile node 110 and mobile node 112. The licensed band radio resource may be indicated by base station 114 to mobile node 110 using, for example, radio resource control signaling. The allocation may be semi-permanent. The allocation may concern radio resources repeating in the time do^¬ main. Together with the allocation may be indicated an index for an indexed radio resource on the unlicensed band by base station 114. After time Tl, the licensed band radio resource comprises a radio resource illus^¬ trated in Figure 1 with block 101. Block 101 may com^¬ prise any number of frequency domain or time domain related radio resources. At time T2, mobile node 110 or base station 114 determines that an unlicensed band radio resource may be used instead of the licensed band radio resource. The time T2 may be indicated by base station 114 to mobile node 110 or it may be de^¬ termined by mobile node 110 based on a timer or a clock. At time T2, base station 114 may indicate to mobile node 110 that it has found unlicensed band ra^¬ dio resource indicated with index 12 to be available. At time T2, mobile node 110 starts to use the unli^¬ censed band radio resource illustrated with block 102. During this time base station 114 may allocate the li^¬ censed band radio resource temporarily for other mo^¬ bile nodes. At time T3, mobile node 110 determines that predefined time duration for the use of the unli^¬ censed band radio resource has expired. In one embodi^¬ ment of the invention, the time duration may be, for example, 40 ms in a non Listen Before Talk (LBT) mode and 13 ms in LBT mode. Base station 114 may assume that mobile node 110 indeed releases the unlicensed band radio resource and stops transmitting data on the unlicensed band radio resource after time T3. At time T3, mobile node starts to use again the licensed band radio resource as illustrated with block 103. During this time the licensed band radio resource may not be used by base station 114 for allocation to other mobile nodes. At time T4, mobile node 110 or base sta^¬ tion 114 determines that an unlicensed band radio re^¬ source may be used instead of the licensed band radio resource. At time T4, mobile node 110 starts to use the unlicensed band radio resource illustrated with block 104. During this time base station 114 may allocate the licensed band radio resource temporarily for other mobile nodes. At time T5, mobile node 110 deter^¬ mines that predefined time duration for the use of the unlicensed band radio resource has expired. Mobile node 110 starts to use the licensed band radio re^¬ source again as illustrated with block 105. At some point in time the device-to-device communication be^¬ tween mobile node 110 and mobile node 112 may stop.

In one embodiment of the invention, the radio resource may be a particular channel, a given number of symbols on a given number of subcarriers, a given number of subcarriers within a symbol time, a number of resource elements, or a number of resource blocks. The radio resource location in terms of frequency and time may be indicated by base station 114 to mobile node 110 regarding the licensed band radio resource. In one embodiment of the invention, the radio resource indexed with the index provided from base station 114 to mobile node 110 is determined by the mobile node 110 by performing a computation of a radio resource block location in time and frequency domains from the index. The radio resource block location may be deter^¬ mined in terms of a subcarrier and a slot.

It should be noted that the number of network elements, mobile node, radio resources and indexes in Figure 1 is just for illustrative purposes. There may be any number of network elements illustrated in Fig^¬ ure 1.

In one embodiment of the invention, base sta^¬ tion 114 may indicate to mobile node 110, at times T2 and T4 that mobile node 110 may perform spectrum sens^¬ ing in the unlicensed band to find an unlicensed band radio resource that is used instead of licensed band radio resource during time intervals T2-T3 and T4-T5. If base station 114 indicates the index of the unli^¬ censed band radio resource, the sensing may be re^¬ stricted to the indexed radio resource in the unli^¬ censed band.

The embodiments of the invention described hereinbefore in association with Figure 1A may be used in any combination with each other. Several of the embodiments may be combined together to form a further embodiment of the invention.

Figure IB illustrates an alternate use of two frequency bands by two mobile nodes in their mutual device-to-device communication in one embodiment of the invention where the mobile node may perform spec^¬ trum scanning to obtain a radio resource in a second frequency band.

At time Tl, base station 114 allocates a li^¬ censed band radio resource for mobile node 110. The licensed band radio resource is illustrated with block 151. After the allocation base station 114 indicates the licensed band radio resource to mobile node 110. Base station 110 also issues an instruction to mobile node 110 to perform spectrum sensing in the unlicensed band to find a radio resource that may be used by mo^¬ bile node 110 in place of the licensed band radio re^¬ source 151. The unlicensed band radio resource may have equal or equivalent communication performance. By communication performance may be meant the throughput or a number of other Quality of Service (QoS) parame^¬ ters. By equivalent communication performance may be meant a communication performance wherein at least one respective QoS parameter of the licensed band radio resource and the unlicensed band radio resource are within a predefined limit. The QoS parameters may com^¬ prise a number of resource blocks, modulation and cod^¬ ing rate. In Figure IB it is assumed that mobile node 110 does not at time Tl find an unlicensed band radio resource. The licensed band radio resource is used for device-to-device communication between mobile node 110 and mobile node 112. At time T2 base station 114 is^¬ sues a new instruction to mobile node 110 to perform spectrum sensing in the unlicensed band to find an available radio resource that may be used by mobile node 110 in place of the licensed band radio resource 151. At time T2, mobile node 110 finds an unlicensed band radio resource illustrated with a box 152 with spectrum sensing. The spectrum sensing may find radio resource 152 due to the fact that it has a noise level that is below a predefined threshold level for an al^¬ lowed noise level. The noise may comprise both trans^¬ missions from other systems and background noise such as Gaussian noise. Mobile node 110 reports at time T2 the finding of radio resource 152 to base station 114. In response, base station 114 may allocate the li^¬ censed band radio resource temporarily for other mo^¬ bile nodes. After the elapsing of a predefined time, at time T3, base station 114 assumes that mobile node 110 automatically releases the unlicensed band radio resource indicated with box 152. Base station 114 is^¬ sues a new instruction to mobile node 110 to perform spectrum sensing in the unlicensed band to find an available unlicensed band radio resource that may be used by mobile node 110 in place of the licensed band radio resource. In Figure IB it is assumed that, at time T3, mobile node 110 does not find an unlicensed band radio resource to be used in place of the li^¬ censed band radio resource such as radio resource il- lustrated with a box 153. Therefore, mobile node 110 uses radio resource 153 until time T4. At time T4, base station 114 issues a new instruction to mobile node 110 to perform spectrum sensing in the unlicensed band to find a radio resource that may be used by mo^¬ bile node 110 in place of the licensed band radio re^¬ source. Mobile node 110 finds unlicensed band radio resource illustrated with a box 154. At time T4, mo^¬ bile node 110 also reports the finding to base station 114, which may allocate the licensed band radio re^¬ source for other use temporarily until time T5. At time T5, base station 114 issues a new instruction to mobile node 110 to perform spectrum sensing in the unlicensed band to find a radio resource that may be used by mobile node 110 in place of the licensed band radio resource. At time T5, mobile node 110 does not find an unlicensed band radio resource. Due to the re^¬ porting of a failure to find an available unlicensed band radio resource to be used in place of the li^¬ censed band radio resource after time T5 or due to lack of such a report at time T5 base station 114 does not use the licensed band radio resource for alloca^¬ tion to other mobile nodes. Mobile node 110 uses after time T5 the licensed band radio resource for device- to-device communication as illustrated with a box 155.

The licensed band radio resource may be indi^¬ cated by base station 114 to mobile node 110 using, for example, radio resource control signaling. The al^¬ location may be semi-permanent. The allocation may concern radio resources repeating in the time domain. Together with the allocation may also be indicated an index for an indexed radio resource on the unlicensed band by base station 114. The index may be a preferred unlicensed band radio resource, but also other unli^¬ censed band radio resource may be found by mobile node 110 in place of the licensed band radio resource in this embodiment. In one embodiment of the invention, mobile node 110 does not receive at times Tl, T2, T3, T4 and T5 instructions from base station 114 to perform spec^¬ trum sensing in the unlicensed band to find a radio resource that may be used by mobile node 110 in place of the licensed band radio resource. Instead, mobile node 110 determines at these intervals that it must perform spectrum sensing in the unlicensed band to find a radio resource that may be used by mobile node 110 in place of the licensed band radio resource. If mobile node 110 finds a radio resource that may be used in place of the licensed band radio resource, mo^¬ bile node 110 reports the finding to the base station. In response to the report of the finding, the base station may allocate the licensed band radio resource for other uses, such as, for other mobile nodes.

In one embodiment of the invention, mobile node 110, at the time determining that the allocation time for the second radio resource has elapsed, deter^¬ mines that it is time to perform spectrum sensing in the unlicensed band to find an available radio re^¬ source that may be used by mobile node 110 in place of the licensed band radio resource. If mobile node 110 finds the available radio resource in the unlicensed band, it indicates the finding of the available radio resource to base station 114. Mobile node 110 may also indicate the failure of finding an available radio re^¬ source in the unlicensed band to base station or the omission of an indication of finding an available radio resource in the unlicensed band may be interpreted by base station 114 as such an indication of failure in finding an available radio resource in the unli^¬ censed band. In response to the report of the finding, base station 114 may allocate the licensed band radio resource for other uses, such as, for other mobile nodes. In response to indication of failure to find an available radio resource on the unlicensed band by mo- bile node 110, base station 114 maintains the first radio resource allocated for mobile node 110 exclusive Only after a report of success in finding an available radio resource on the unlicensed band from mobile node 110, may base station 114 allocate the first radio re^¬ source for other mobile nodes temporarily or for other use .

The embodiments of the invention described hereinbefore in association with Figures 1A and IB may be used in any combination with each other. Several of the embodiments may be combined together to form a further embodiment of the invention.

Figure 2A is a first part of a flow chart il^¬ lustrating a method for frequency band switching in a base station in one embodiment of the invention.

At step 200 a base station indicates a radio resource comprised on a licensed band to a mobile node The radio resource may be indicated generally for any traffic originating from the mobile node, the traffic comprising both uplink transmissions and device-to- device transmission. The radio resource may be indi^¬ cated separately for device-to-device transmission. The resource may be allocated for the mobile node un^¬ til the allocation is released at the request of ei^¬ ther the mobile node or the base station. The radio resource may be a periodically occurring radio re^¬ source. The radio resource may be allocated by the base station using a physical layer scheduling grant or it may be configured using Radio Resource Control (RRC) signaling.

At the step 202 the base station indicates an index referring to a radio resource comprised on an unlicensed band to the mobile node. The index may be used by the mobile node to determine at least one of a sub-carrier and a number of symbols within the unlicensed band. The index may be associated with the ra^¬ dio resource comprised on the licensed band, for exam- pie, based on a derivation of a identifier of the radio resource comprised on the licensed band, for exam^¬ ple, the identifier comprising at least one of an identifier for a sub-carrier and an identifier for at least one symbol.

At step 204 the base station determines whether it is to perform radio resource sensing for the indexed radio resource. The radio resource sensing may be used to determine whether the indexed radio re^¬ source within the unlicensed band is available.

At step 206 is checked the result of step 204. If the base station is to perform the radio resource sensing, the method branches to step 208, otherwise the method branches to step 216.

At step 208 the base station checks the availability of the indexed radio resource on the unlicensed band. The checking may involve a use of ra^¬ dio resource sensing to determine whether the indexed radio resource within the unlicensed band is available. The aim of the spectrum sensing may be to determine, if the radio resource indexed with the index indicated at step 202 to the mobile node has a noise level above a predefined threshold value. Since the base station is not receiving any transmissions directed to it on the radio resource, the base station may assume that any signals on the radio resource are currently noise. The predefined threshold value is a criterion for judging whether the radio resource is being currently used or not. If the noise level is above the prede^¬ fined threshold, the radio resource is judged as used. The checking may involve also an allocation of the ra^¬ dio resource for the mobile node by the base station. In the allocation, the base station may mark in a memory of the base station the radio resource as allo^¬ cated for the mobile node. After the checking of the availability of the radio resource, the base station may instruct the mobile node to use the indexed radio resource on the unlicensed band.

At step 210 is checked the result of step 208 of resource sensing to check the availability of the indexed radio resource on the unlicensed band. If the checking is successful and the indexed radio resource is available, the method continues at step 212. Other^¬ wise the method continues at step 214 and the licensed band radio resource must be used.

At step 212 the base station instructs the mobile node to start to use the indexed radio resource on the unlicensed band. The base station may send a message to the mobile node that issues the instruction to start to use the indexed radio resource indicated previously at step 202 to the mobile node. Thereupon, the method continues at label A in Figure 2B.

At step 214 the base station instructs the mobile node to start to use the licensed band radio resource indicated at step 200, for example, for de^¬ vice-to-device communication from the mobile node. Thereupon, the method continues at label B in Figure 2B.

At step 216 the base station instructs the mobile node to check the availability of the indexed radio resource on the unlicensed band. The checking may involve the sensing of the indexed radio resource. Thereupon, the method continues at label C in Figure 2B.

In one embodiment of the invention, the radio resource sensing comprises finding whether a noise level of the radio resource is below a predefined threshold level for an allowed noise level. The noise may comprise both transmissions from other systems and background noise such as Gaussian noise.

Figure 2B is a second part of a flow chart illustrating a method for frequency band switching in a base station in one embodiment of the invention. At step 218 the base station waits for a re^¬ port from the mobile node. The report concerns whether the mobile node has successfully reserved the unli^¬ censed band radio resource. If there is no report or the report reveals an unsuccessful outcome, the method continues at label E in Figure 2A and the licensed band radio resource must be used. Otherwise, the method continues at step 218.

At step 220 the base station allocates the licensed band radio resource to another mobile node temporarily. The duration of the allocation may be set not to be longer than the time in which the mobile node automatically released the unlicensed band radio resource .

At step 222 the base station assumes the re^¬ lease of the radio resource on the unlicensed band automatically by the mobile node.

At step 224 is checked if the method is at end. If the method is not at end it continues at label D in Figure 2A. Otherwise, the method is finished.

Figure 3A is a flow chart illustrating a first part of a method for frequency band switching in a mobile node in one embodiment of the invention.

At step 300 the mobile node receives an indi^¬ cation of a radio resource comprised in a licensed band. The indication may separately indicate that the radio resource is to be used for device-to-device transmission in particular.

At step 302 the mobile node receives from the base station an index referring to a radio resource comprised on an unlicensed band. The index may be used by the mobile node to determine at least one of a sub- carrier and a number of symbols within the unlicensed band .

At step 304 the mobile node determines if it must perform radio resource sensing for the indexed radio resource on the licensed band. The mobile node determines this based on instructions from the base station. If the mobile node must perform radio re^¬ source sensing, the method continues at step 306, oth^¬ erwise the method continues at step 314.

At step 306 the mobile node receives instruc^¬ tions from the base station to do radio resource sens^¬ ing and to check the availability of the indexed radio resource within the unlicensed band.

At step 308 the mobile node performs radio resource sensing for the indexed radio resource on the unlicensed band. The checking may involve a use of ra^¬ dio resource sensing to determine whether the indexed radio resource within the unlicensed band is available The aim of the radio resource sensing may be to deter^¬ mine, if the radio resource indexed with the index in^¬ dicated at step 302 to the mobile node has a noise level above a predefined threshold value. Since the mobile node is not receiving any transmissions di^¬ rected to it on the indexed radio resource, the base station may assume that any signals on the radio re^¬ source are currently noise. The predefined threshold value is a criterion for judging whether the radio resource is being currently used or not. If the noise level is above the predefined threshold, the radio re^¬ source is judged as used.

At step 310 is checked the outcome of the ra^¬ dio resource sensing and the checking of the avail^¬ ability of the indexed radio resource at step 308. If the outcome is that the radio resource is available, the method continues at step 312.

At step 312 the mobile node reports the availability of the indexed radio resource to the base station. The report is needed by the base station if the base station does not perform the checking of the availability of the indexed radio resource on the unlicensed band. Thereupon, the method continues at label A in Figure 3B. At step 314 the mobile node checks the in^¬ structions from the base station whether the mobile node must use the licensed band radio resource or the unlicensed band radio resource. If the mobile node must use the licensed band radio resource, the method continues at step 316. Otherwise, the method continues at label B in Figure 3B.

At step 316 the mobile node receives instruc^¬ tions to start to use the licensed band radio resource Thereupon, the method continues at label C in Figure 3B.

Figure 3B is a flow chart illustrating a sec^¬ ond part of a method for frequency band switching in a mobile node in one embodiment of the invention.

At step 318 the mobile node performs device- to-device communication on the licensed band with a remote device.

At step 320 the mobile node receives instruc^¬ tions to start to use the indexed radio resource on the unlicensed band directly without spectrum sensing. The radio resource is the radio resource indicated at step 302. The index may be used by the mobile node to determine at least one of an actual sub-carrier and a number of symbols within the unlicensed band.

At step 322 the mobile node performs device- to-device communication with a remote node on the unlicensed band. The device-to-device communication may be performed according to the method illustrated in Figure 4.

At step 318 it is checked if the method is at end. If the method is not at end, the method continues at label D in Figure 3A. Otherwise, the method is fin^¬ ished .

In one embodiment of the invention, the mo^¬ bile node does not receive the index at step 302. In^¬ stead, if the base station indicates that the mobile node must perform sensing at step 306, it may give the mobile node a freedom to perform radio resource or spectrum sensing in the area of the unlicensed band that is not restricted to the indexed radio resource. As a result of the spectrum sensing, the mobile node may obtain an available radio resource on the unli^¬ censed band that provides a throughput comparable or equivalent to the licensed band radio resource. The mobile node may report the finding of the available unlicensed band to the base station at step 312.

Figure 4 is a flow chart illustrating a method for radio system selection in a mobile node in one embodiment of the invention.

At step 400 a noise level is determined on an unlicensed band. The noise level may be determined for the unlicensed band generally or for the indexed radio resource indicated to the mobile node at step 302 of Figure 3A.

At step 402 is determined whether the noise level exceeds a predefined threshold. If the noise level does not exceed a predefined threshold, the unlicensed band is considered to be on for the device- to-device transmission.

At step 404 is checked the outcome of step 402. If the unlicensed band is on, the method contin^¬ ues at step 406.

At step 406 a Long-Term Evolution (LTE) radio mode is selected at the mobile node.

At step 408 at least one Wireless Local Area Network (WLAN) radio circuit is switched off in the mobile node. To the term WiFi may also be used to re^¬ fer to a WLAN radio circuit. Thereupon, the method is finished. The method may be repeated at a later time or periodically to re-check the noise level on the unlicensed band.

At step 410 a WLAN radio mode is selected in the mobile node. At step 412, if there is data to transmit to a remote node, the mobile node signals the acquisition of an unlicensed band radio resource to at least one remote node. The acquisition is signaled by transmit^¬ ting at least one WLAN radio frame.

At step 414 the mobile node finishes the transmitting of any pending data from an upper protocol layer using at least one WLAN radio frame, if part of the pending data has already been sent at step 412 in one of the WLAN radio frames sent at step 412.

At step 416 the mobile node continues the de^¬ vice-to-device transmission by transmitting at least one Long-Term Evolution symbol on the unlicensed band radio resource. The transmission may be within an LTE radio frame, subframe or slot in accordance with tim^¬ ing shared between the mobile node and the remote node. Thereupon, the method is finished. The method may be performed periodically in association with the method of Figures 3A and 3B.

The embodiments of the invention described hereinbefore in association with Figures 2A, 2B, 3A, 3B and 4 may be used in any combination with each other. Several of the embodiments may be combined to^¬ gether to form a further embodiment of the invention.

Figure 5 is a block diagram illustrating an apparatus in one embodiment of the invention. In Fig^¬ ure 5 there is an apparatus 500, which is, for example, a mobile node, user equipment, a handset, a cellular phone, a mobile terminal, an Application Specific In^¬ tegrated Circuit (ASIC), a chip or a chipset. Appara^¬ tus 500 may correspond to a mobile node illustrated in Figures 1, 2, 3A, 3B and 4. The internal functions of apparatus 500 are illustrated with a box 502. Appara^¬ tus 500 may comprise at least one antenna 510. There may be multiple input and output antennas. In associa^¬ tion with apparatus 500 there is Radio Frequency (RF) circuit 512. RF circuit 512 may be also any circuit or may be referred to as circuit 512. RF circuit 512 is communicatively connected to at least one processor 514. Connected to processor 514 there may be a first memory 520, which is, for example, a Random Access Memory (RAM) . There may also be a second memory 522, which may be a non-volatile memory, for example, an optical or magnetic disk. There may also be a User In^¬ terface (UI) 516 and a display 518. In memory 520 there may be stored software relating to functional entities 532 and 534. An RF entity 532 communicates with RF circuit 512 to perform radio resource alloca^¬ tion, de-allocation, signaling plane and user plane data transmission and reception. RF entity 532 receives an indication of radio resources to be used and request to perform device-to-device transmission from a base station via a protocol stack 534. Protocol stack entity 534 comprises control plane protocol functions related to the interface towards an eNB or any base station. Protocol stack entity 534 also comprises protocol functionalities related to user plane device-to-device transmission. Protocol stack entity 534 may comprise, for example, an internet protocol stack. RF circuit 512 may comprise a transmitter for SC-FDMA and a receiver and a transmitter for OFDMA. RF circuit 512 may also comprise a receiver for SC-FDMA. RF circuit 512 may also comprise a transmitter and a receiver circuit for WLAN transmission or reception.

When the at least one processor 514 executes functional entities associated with the invention, memory 520 comprises entities such as, any of the functional entities 532 and 534. The functional enti^¬ ties within apparatus 500 illustrated in Figure 5 may be implemented in a variety of ways. They may be im^¬ plemented as processes executed under the native oper^¬ ating system of the network node. The entities may be implemented as separate processes or threads or so that a number of different entities are implemented by means of one process or thread. A process or a thread may be the instance of a program block comprising a number of routines, that is, for example, procedures and functions. The functional entities may be imple^¬ mented as separate computer programs or as a single computer program comprising several routines or functions implementing the entities. The program blocks are stored on at least one computer readable medium such as, for example, a memory circuit, memory card, magnetic or optical disk. Some functional entities may be implemented as program modules linked to another functional entity. The functional entities in Figure 4 may also be stored in separate memories and executed by separate processors, which communicate, for example, via a message bus or an internal network within the network node. An example of such a message bus is the Peripheral Component Interconnect (PCI) bus.

Figure 6 is a block diagram illustrating an apparatus in one embodiment of the invention. In Fig^¬ ure 6 there is an apparatus 600, which is, for example, a base station, an Evolved Node B, a base station server, a chip or a chipset. Apparatus 600 may corre^¬ spond to a base station illustrated in Figures 1, 2, 3A, 3B and 4. The internal functions of apparatus 600 are illustrated with a box 602. Apparatus 600 may com^¬ prise at least one antenna 610. There may be multiple input and output antennas. In association with appara^¬ tus 600 there is Radio Frequency (RF) circuit 612. RF circuit 612 may be also any circuit or may be referred to as circuit 612. RF circuit 612 is communicatively connected to at least one processor 614. Connected to processor 614 there may be a first memory 620, which is, for example, a Random Access Memory (RAM) . There may also be a second memory 622, which may be a non^¬ volatile memory, for example, an optical or magnetic disk. There may also be a User Interface (UI) 616 and a display 618. In memory 620 there may be stored soft- ware relating to functional entities 632 and 634. An RF entity 632 communicates with RF circuit 612 to per^¬ form radio resource allocation, de-allocation, signaling plane transmission and reception. RF entity 632 receives requests for radio resources from mobile nodes and gives indications of radio resources to be used for device-to-device transmission to mobile nodes via a protocol stack 634. Protocol stack entity 634 comprises control plane protocol functions related to the interface towards a mobile node. RF circuit 612 may comprise a receiver for SC-FD A and a transmitter for OFDMA.

When the at least one processor 614 executes functional entities associated with the invention, memory 620 comprises entities such as, any of the functional entities 632 and 634. The functional enti^¬ ties within apparatus 600 illustrated in Figure 6 may be implemented in a variety of ways. They may be im^¬ plemented as processes executed under the native oper^¬ ating system of the network node. The entities may be implemented as separate processes or threads or so that a number of different entities are implemented by means of one process or thread. A process or a thread may be the instance of a program block comprising a number of routines, that is, for example, procedures and functions. The functional entities may be imple^¬ mented as separate computer programs or as a single computer program comprising several routines or functions implementing the entities. The program blocks are stored on at least one computer readable medium such as, for example, a memory circuit, memory card, magnetic or optical disk. Some functional entities may be implemented as program modules linked to another functional entity. The functional entities in Figure 4 may also be stored in separate memories and executed by separate processors, which communicate, for example, via a message bus or an internal network within the network node. An example of such a message bus is the Peripheral Component Interconnect (PCI) bus.

The exemplary embodiments of the invention can be included within any suitable device, for exam^¬ ple, including any suitable servers, workstations, PCs, laptop computers, PDAs, Internet appliances, handheld devices, cellular telephones, wireless devices, other devices, and the like, capable of performing the proc^¬ esses of the exemplary embodiments, and which can com^¬ municate via one or more interface mechanisms, includ^¬ ing, for example, Internet access, telecommunications in any suitable form (for instance, voice, modem, and the like) , wireless communications media, one or more wireless communications networks, cellular communica^¬ tions networks, 3G communications networks, 4G commu^¬ nications networks Public Switched Telephone Network (PSTNs) , Packet Data Networks (PDNs) , the Internet, intranets, a combination thereof, and the like.

It is to be understood that the exemplary em^¬ bodiments are for exemplary purposes, as many varia^¬ tions of the specific hardware used to implement the exemplary embodiments are possible, as will be appre^¬ ciated by those skilled in the hardware art(s) . For example, the functionality of one or more of the com^¬ ponents of the exemplary embodiments can be imple^¬ mented via one or more hardware devices, or one or more software entities such as modules.

The exemplary embodiments can store informa^¬ tion relating to various processes described herein. This information can be stored in one or more memories, such as a hard disk, optical disk, magneto-optical disk, RAM, and the like. One or more databases can store the information regarding cyclic prefixes used and the delay spreads measured. The databases can be organized using data structures (e.g., records, tables, arrays, fields, graphs, trees, lists, and the like) included in one or more memories or storage devices listed herein. The processes described with respect to the exemplary embodiments can include appropriate data structures for storing data collected and/or gen^¬ erated by the processes of the devices and subsystems of the exemplary embodiments in one or more databases.

All or a portion of the exemplary embodiments can be implemented by the preparation of one or more application-specific integrated circuits or by inter^¬ connecting an appropriate network of conventional com^¬ ponent circuits, as will be appreciated by those skilled in the electrical art(s).

As stated above, the components of the exem^¬ plary embodiments can include computer readable medium or memories according to the teachings of the present inventions and for holding data structures, tables, records, and/or other data described herein. Computer readable medium can include any suitable medium that participates in providing instructions to a processor for execution. Such a medium can take many forms, including but not limited to, non-volatile media, vola^¬ tile media, transmission media, and the like. Non^¬ volatile media can include, for example, optical or magnetic disks, magneto-optical disks, and the like. Volatile media can include dynamic memories, and the like. Transmission media can include coaxial cables, copper wire, fiber optics, and the like. Transmission media also can take the form of acoustic, optical, electromagnetic waves, and the like, such as those generated during radio frequency (RF) communications, infrared (IR) data communications, and the like. Com^¬ mon forms of computer-readable media can include, for example, a floppy disk, a flexible disk, hard disk, magnetic tape, any other suitable magnetic medium, a CD-ROM, CDRW, DVD, any other suitable optical medium, punch cards, paper tape, optical mark sheets, any other suitable physical medium with patterns of holes or other optically recognizable indicia, a RAM, a PROM, an EPROM, a FLASH-EPROM, any other suitable memory chip or cartridge, a carrier wave or any other suitable medium from which a computer can read.

While the present inventions have been de^¬ scribed in connection with a number of exemplary embodiments, and implementations, the present inventions are not so limited, but rather cover various modifica^¬ tions, and equivalent arrangements, which fall within the purview of prospective claims.

The embodiments of the invention described hereinbefore in association with the figures presented may be used in any combination with each other. Several of the embodiments may be combined together to form a further embodiment of the invention.

It is obvious to a person skilled in the art that with the advancement of technology, the basic idea of the invention may be implemented in various ways. The invention and its embodiments are thus not limited to the examples described above; instead they may vary within the scope of the claims .

Claims

WHAT IS CLAIMED IS :

1. A method, comprising:

receiving, in a mobile node, an indication of a first radio resource on a first frequency band;

determining, in the mobile node, that a second ra^¬ dio resource on a second frequency band is available for transmitting data to a remote node;

transmitting, by the mobile node, data to the re^¬ mote node using the second radio resource;

determining, by the mobile node, that an alloca^¬ tion time for the second radio resource has elapsed; determining, in the mobile node, a failure to find an available radio resource on the second frequency band; and

transmitting, by the mobile node, data to the re^¬ mote node using the first radio resource, in response to the determining of the failure to find the avail^¬ able radio resource on the second frequency band.

2. The method according to claim 1, wherein the step of determining the failure to find the avail^¬ able radio resource on the second frequency band com^¬ prises :

receiving a message indicating the failure to find the available radio resource from a base station.

3. The method according to claim 1, wherein the step of determining the failure to find the avail^¬ able radio resource on the second frequency band com^¬ prises :

performing spectrum sensing by the mobile node of at least one of the second radio resource and the sec^¬ ond frequency band; and

determining, in response to the sensing, the failure to find the available radio resource.

4. The method according to claim 1, the method further comprising: receiving, in the mobile node, an indication of an index corresponding to the second radio resource on a second frequency band.

5. The method according to claim 1, wherein the step of determining that the second radio resource is available for transmitting data to a remote node comprises :

receiving an assignment indicating the availabil^¬ ity of the second radio resource.

6. The method according to claim 1, the method further comprising:

transmitting, from the mobile node, to a base sta^¬ tion a report indicating successful determination of the availability of the second radio resource.

7. The method according to claim 1, wherein the step of determining that a second radio resource is available for transmitting data to a remote node comprises :

determining, in response to the sensing, the availability of the second radio resource.

8. The method according to claim 1, the method further comprising:

transmitting, by the mobile node, a report to a base station indicating release of the second radio resource .

9. The method according to claim 1, wherein the first radio resource is comprised in a licensed frequency band and the second radio resource is com^¬ prised in an unlicensed frequency band.

10. The method according to claim 9, the method further comprising:

determining a noise level on the second frequency band; determining whether noise level exceeds a prede^¬ fined threshold; and

entering an unlicensed radio band mode in the mo^¬ bile node in response to the noise level exceeding the predefined threshold.

11. The method according to claim 10, wherein in the unlicensed radio band mode at least one wire^¬ less local area network circuit is switched off.

12. The method according to claim 9, the method further comprising:

determining a noise level on the second frequency band;

determining whether the noise level exceeds a pre^¬ defined threshold; and

entering a licensed radio band mode in the mobile node in response to the noise level being below the predefined threshold.

13. The method according to claim 12, wherein the step of determining that the second radio resource is available for transmitting data to a remote node further comprises:

transmitting a wireless local area network radio frame to the remote node.

14. The method according to claim 1, wherein the mobile node comprises at least one of a handset, a chipset, a mobile device and a mobile terminal.

15. A method, comprising:

allocating a first radio resource on a first fre^¬ quency band to a first mobile node;

transmitting, from a base station, an indication of the first radio resource;

determining, in the base station, that a second radio resource on a second frequency band is reserved for a first mobile node;

allocating the first radio resource, by the base station, to a second mobile node temporarily; determining, in the base station, that no radio resource on the second frequency band is reserved for the first mobile node; and

maintaining the first radio resource exclusively allocated to the first mobile node in response to the determining that no radio resource on the second fre^¬ quency band is reserved for the first mobile node.

16. The method according to claim 15, the method further comprising:

transmitting, from the base station, an indication of an index corresponding to the second radio resource on the second frequency band.

17. The method according to claim 15, wherein the step of determining that the second radio resource is reserved for the first mobile node further com^¬ prises :

receiving an indication of the reservation from the first mobile node.

18. The method according to claim 15, wherein the step of determining that the second radio resource is reserved for the first mobile node further com^¬ prises :

allocating the second radio resource for the first mobile node.

19. The method according to claim 15, wherein the method further comprises:

performing spectrum sensing of the second radio resource by the base station; and

determining, in response to the sensing, an availability of the second radio resource.

20. An apparatus, comprising:

at least one processor configured

to receive an indication of a first radio resource on a first frequency band,

to determine that a second radio resource on a second frequency band is available for transmitting data to a remote node, to transmit data to the remote node using the sec^¬ ond radio resource,

to determine that an allocation time for the sec^¬ ond radio resource has elapsed,

to determine, in the mobile node, a failure to find an available radio resource on the second fre^¬ quency band, and

to transmit data to the remote node using the first radio resource, in response to the determining of the failure to find the available radio resource on the second frequency band.

21. An apparatus, comprising:

at least one processor configured

to allocate a first radio resource on a first fre^¬ quency band to a first mobile node,

to transmit an indication of the first radio re^¬ source to the first mobile node,

to determine that a second radio resource on a second frequency band is reserved for a first mobile node,

to allocate the first radio resource to a second mobile node temporarily,

to determine that no radio resource on the second frequency band is reserved for the first mobile node, and

to maintain the first radio resource exclusively allocated to the first mobile node in response to the determining that no radio resource on the second fre^¬ quency band is reserved for the first mobile node.

22. A system according to claim 20 and claim

21.

23. The apparatus according to claim 19, wherein the apparatus comprises a base station.

24. A computer program comprising code adapted to cause the following when executed on a data-processing system: receiving, in a mobile node, an indication of a first radio resource on a first frequency band;

25. The computer program according to claim 24, wherein said computer program is stored on a computer readable medium.

26. A computer program comprising code adapted to cause the following when executed on a data-processing system:

transmitting, from a base station, an indication of the first radio resource to the first mobile node; determining, in the base station, that a second radio resource on a second frequency band is reserved for the first mobile node;

allocating the first radio resource, by the base station, to a second mobile node temporarily;

determining, in the base station, that no radio resource on the second frequency band is reserved for the first mobile node; and

27. The computer program according to claim 26, wherein said computer program is stored on a computer readable medium.