Terminal and a method for establishing a cellular network connection between a terminal and a base station

A terminal may include a generator configured to generate a request for radio network resources from a cellular network; a transmitter configured to transmit the request for radio network resources to a relay device, wherein the request for radio network resources may be configured to be forwarded by the relay device to a base station of the cellular network; and a controller configured to establish a cellular network connection between the terminal and the base station of the cellular network using radio network resources assigned to the terminal by the cellular network.

TECHNICAL FIELD

Various aspects relate to a terminal and a method for establishing a cellular network connection between a terminal and a base station.

BACKGROUND

Mobile radio communication terminal devices may perform a random access procedure in order to establish a cellular network connection with a base station. A mobile radio communication terminal device may randomly select a mobile radio resource for transmission from a predefined set of mobile radio resources. A mobile radio resource may be, for example, a certain time slot at a certain radio frequency with a certain access code. This access scheme may be subject to collisions as a requesting mobile radio communication terminal device may request the same mobile radio resources already selected by another mobile radio communication terminal device. Collisions may waste mobile radio resources and may increase transmission delays.

SUMMARY

A terminal may include a generator configured to generate a request for radio network resources from a cellular network; a transmitter configured to transmit the request for radio network resources to a relay device, wherein the request for radio network resources may be configured to be forwarded by the relay device to a base station of the cellular network; and a controller configured to establish a cellular network connection between the terminal and the base station of the cellular network using radio network resources assigned to the terminal by the cellular network.

A method for establishing a cellular network connection between a terminal and a base station may include generating a request for radio network resources from a cellular network; transmitting the request for radio network resources to a relay device, wherein the request for radio network resources may be configured to be forwarded by the relay device to the base station of the cellular network; and establishing a cellular network connection between the terminal and the base station of the cellular network using radio network resources assigned to the terminal by the cellular network.

DESCRIPTION

The following detailed description refers to the accompanying drawings that show, by way of illustration, specific details and aspects in which the invention may be practised. These aspects are described in sufficient detail to enable those skilled in the art to practice the invention. Other aspects may be utilized and structural, logical, and electrical changes may be made without departing from the scope of the invention. The various aspects are not necessarily mutually exclusive, as some aspects can be combined with one or more other aspects to form new aspects. Various aspects are described for structures or devices, and various aspects are described for methods. It may be understood that one or more (e.g. all) aspects described in connection with structures or devices may be equally applicable to the methods, and vice versa.

The term “cellular network” is used herein to refer to a radio communications system configured in accordance with the network architecture of any one of, or any combination of, LTE (Long Term Evolution) cellular communications technology, UMTS (Universal Mobile Telecommunications System) cellular communications technology which may include the system enhancement HSPA (High Speed Packet Access), GSM (Global System for Mobile Communications) cellular communications technology which may include system enhancements General Packet Radio System (GPRS) and Enhanced Data rates for GSM Evolution (EDGE) and CDMA2000 (Code Division Multiple Access) cellular communications technology, although other cellular communications technology may be possible as well.

The terms “network”, “cellular network”, “cellular network communications system”, “cellular radio communications technology” and “cellular communications system” may refer to the same logical entity and may be used interchangeably throughout the entire description.

The communications system100may be configured in accordance with the network architecture of any one of, or any combination of, LTE (Long Term Evolution) cellular communications technology, UMTS (Universal Mobile Telecommunications System) cellular communications technology, GSM (Global System for Mobile Communications) cellular communications technology, and CDMA2000 (Code Division Multiple Access) cellular communications technology, although other cellular communications technology may be possible as well.

A terminal102, such as, for example, a UE (user equipment) equipped with a SIM (Subscriber Identity Module) running on a UICC (Universal Integrated Circuit Card), may be within the area of coverage of a cellular network104, such as, for example, a PLMN (Public Land Mobile Network). The area of coverage of the cellular network104may be the aggregate result of the coverage of at least one base station belonging to the cellular network104, such as, for example, one, two, three, four, five, six, seven, eight, nine, ten or even more base stations belonging to the cellular network104, such as tens or hundreds of base stations belonging to the cellular network104. By way of an example, the area of coverage of the cellular network104inFIG. 1may at least be the aggregate result of the coverage of base stations106a,106b, and106cand others belonging to the cellular network104(other base stations not shown inFIG. 1).

InFIG. 1, each base station106a,106b, and106cmay be configured to transmit a downlink (DL) signal at a particular power to cover a particular geographical area. By way of an example, base station106amay be configured to transmit DL signal108a; base station106bmay be configured to transmit DL signal108b; and base station106cmay be configured to transmit DL signal108c. The geographical area covered by a particular base station106a,106b, or106cmay be substantially (namely, approximately) represented by a cell. By way of an example, the area of coverage of base station106amay be substantially represented by cell105a; the area of coverage of base station106bmay be substantially represented by cell105b; and the area of coverage of base station106cmay be substantially represented by cell105c. Accordingly, the area of coverage of the cellular network104may be the result of at least one cell, or the result of a tessellation of a plurality of cells, wherein each cell is an approximation of the area of coverage of a particular base station. By way of an example, area of coverage of the cellular network104may be the result of the tessellation of cells105a,105b, and105c, wherein each cell is an approximation of the area of coverage of base stations106a,106b, and106c, respectively.

Each cell105a,105b, and105cmay be an approximation of the area of coverage of a particular base station106a,106b,106c. Nonetheless, there may be geographical regions that may be served by more than one base station. By way of an example, the geographical region on either side of the boundary formed between points1A and1B ofFIG. 1may be served by at least one of base stations106aand106b; the geographical region on either side of the boundary formed between points1B and1C of may be served by at least one of base stations106aand106c; and the geographical region on either side of the boundary formed between points1B and1D of may be served by at least one of base stations106band106c.

A random access procedure may be used in the cellular communication system100when the terminal102with no cellular connection wants to establish a connection with the cellular network104(e.g. with any one of base station106a,106b,106cof the cellular network104). For example, a random access procedure may be used when a UE in an idle mode (e.g. in radio resource control (RRC) state RRC_IDLE in an LTE cellular network) wants to switch to a connected mode (e.g. to a “RRC_CONNECTED” state in an LTE cellular network). In an LTE cellular network, the following events may require a random access procedure:

1. An idle terminal102(e.g. UE) accesses the cellular network104(e.g. initial access from RRC_IDLE state);

2. A connected terminal102loses the connection and re-connects (e.g. connection re-establishment, for example after a radio link failure);

3. The cellular network104instructs a terminal102to handover to another mobile radio cell (e.g. from cell105bto cell105a);

4. Data for a connected terminal102arrives at a mobile radio core network, but the connected terminal's downlink is not synchronized (e.g. downlink (DL) data arrival during the RRC_CONNECTED state requiring radio access (RA) procedure);

5. A connected terminal102is instructed to transmit data, but the connected terminal's uplink is not synchronized (e.g., uplink (UL) data arrival during the RRC_CONNECTED state requiring radio access (RA) procedure); and

6. Positioning a terminal102when the terminal102is in a connected mode (e.g. RRC_CONNECTED state).

The aforementioned list of events is not exhaustive, and other events in an LTE cellular network may require a random access procedure.

In general, two types of random access procedures may be available. The first is contention based random access, and the second is non-contention based random access.

In contention based random access, a RACH (Random Access Channel) resource (e.g. time-slot and/or frequency band) may be selected randomly by each UE from the same set of resources. If two or more UEs transmit during overlapping time-slots and/or frequency bands, contention (e.g. collision) may be likely. In non-contention based random access, a unique RACH resource (e.g. a RACH preamble) may be assigned (namely, dedicated) to a UE, and the UE may be required to send an UL transmission including the unique RACH resource (e.g. the RACH preamble) within a certain time period, for example within a multiple of a TTI (Transmission time Interval) of the cellular network. Since the RACH resource is dedicated to the UE, contention may not occur.

FIG. 2AandFIG. 2Bshow message flows for performing contention and non-contention based random access procedure between a user equipment and a base station

As shown inFIG. 2A, the UE202may randomly choose a preamble at206when performing a contention-based random access procedure. The UE202may transmit the preamble to base station204in the next available RACH occasion at208. For example, the RACH occasion may be a position in frequency and/or time at which the UE202may send an UL transmission to the base station204. The position in frequency and/or time of these RACH occasions may be configured by the mobile radio network and broadcasted by the base station204to the UE202within the system information. If a collision occurs at208, the UE202may restart the contention based random access procedure.

The UE202may listen for a response210from the base station204and may obtain information about the mobile radio resources to use for a scheduled transmission. Random Access Response210may contain, among other things, the received random access preamble ID (RAPID) of UE202; information about a mobile radio resource, for example time slot (e.g. timing alignment information) and/or frequency band, assigned to the UE202; and a cell radio network temporary ID (C-RNTI) assigned to the UE202. After reception of the response210, UE202may transmit the scheduled transmission212using the assigned mobile radio resource, and may listen for a subsequent response from base station204(e.g. contention resolution response214). The response214may indicate whether the message212is received without contention. If a collision occurs during the scheduled transmission212, the UE202may restart the contention based random access procedure. For subsequent random access procedures, the same procedure may be repeated (indicated by arrow216). In other words, the UE202may randomly select another preamble each time UE202transmits a message and/or experiences a collision.

As shown inFIG. 2B, UE202may be scheduled for non-contention based transmission and may obtain a dedicated preamble at218from base station204prior to the start of the transmission of UE202. The transmission is non-contention based because base station204selects an unused preamble for UE202. At220, UE202may decide to transmit the assigned preamble in the next available RACH occasion and listens to the response from base station204. The UE202may be required to transmit the assigned preamble within a certain time period. If the certain time period expires, the assigned preamble may be released by the base station204, and the UE202may be required to obtain another dedicated preamble from the base station204. Base station204sends a random access response222to the UE202. The random access response202may contain, among other things, the received random access preamble ID (RAPID) of UE202; information about a mobile radio resource, for example time slot (e.g. timing alignment information) and/or frequency band, assigned to the UE202; and a cell radio network temporary ID (C-RNTI) assigned to the UE202. After reception of the response222, UE202may transmit a scheduled transmission, such as, for example scheduled transmission212inFIG. 2A, using the assigned mobile radio resource.

Non-contention based random access procedure may be faster and more reliable than the contention-based procedure, since less contentions (e.g. collisions) occur and less time may be spent restarting the random access procedure due to the contentions. However, a non-contention based random access procedure may require a connection setup prior to the execution, which may not always be possible. Further, the number of dedicated preambles may be limited.

Contention based random access procedure may be used in the first five events described above (i.e. not for positioning purposes), while non-contention based random access procedure may be used for the following events: handover, DL data arrival, and positioning.

Table 1 gives an overview of the messages exchanged between a UE and a radio access network (RAN) during initial access of the UE to the cellular network. Table 1 may be directed to “RRC connection establishment” procedure in an LTE cellular network, but the principles may be application to a cellular network configured in any other network architecture (e.g. GSM, CDMA2000, UMTS).

The connection establishment procedure may include a first part including a random access procedure executed on a RACH (random access channel) and/or a DL-SCH (Downlink shared channel), and a second part executed on CCCH (Common Control Channel) and/or DCCH (Dedicated Control Channel).

The resources on the RACH may be limited and may be affected by the risk of contention. As described above, a RACH resource may be defined by a certain time instance (e.g. timing alignment, timing advance, time slot), a certain frequency sub-band, and a certain access code (e.g. a preamble). Each time a contention on the RACH occurs, i.e. two or more mobile devices (e.g. UEs) have randomly selected the same resource for transmission, the random access may fail. When the random access fails, the access attempt may be repeated and the used resources may be wasted, as described in relation toFIG. 1A. To avoid such contention, the RACH resources may be configured in each cell to be sufficient in most cases. For example, the number of RACH resources may be substantially matched to the number of mobile devices in the cell. However, RACH resources may be reserved permanently, and this may limit the resources that are available for other uses, e.g. user data. Therefore, there may exist a trade off between sufficient resources for RACH, and not reducing too many resources for other kinds of communication (e.g. user data exchange).

Whilst contention (e.g. collisions) on a RACH may be possible, some situations may increase the likelihood of such contention. For example, the following situations as identified at 3GPP (3rd Generation Partnership Project) may increase the chances of collisions on a RACH.

Firstly, a large number of MTC (Machine-type Communication) devices may be deployed in a cell. The number of MTC devices may be a multiple of devices used by human users. Typically, the amount of data to be transmitted by MTC devices is low, but each new transmission may require a random access (i.e. a switch from “idle mode” to “connected mode” of operation). In some situations (e.g. when devices are supplied with power after a power disruption and/or when a triggering event occurs), many MTC devices may attempt to perform a random access simultaneously. This may lead to many RACH contentions, which may affect MTC devices and devices used by human users alike.

Secondly, the number of devices used by human users may be large (e.g. in big cities, such as, for example Tokyo, New York, etc.), and may be moving together (e.g. in a subway during rush hour). Each time the large number of devices used by human users passes certain areas (e.g. routing area), all UEs in “idle mode” may have to perform a random access to inform the network about their new location. Therefore, many such devices may try to perform the random access procedure simultaneously, which may lead to a RACH contention.

3GPP may offer some measures to reduce the chances of RACH contention in the above-mentioned situations. For example, devices (e.g. UEs and/or MTC devices) may indicate to the network (e.g. a base station of the network) during random access that they are delay tolerant. In other words, devices that may perform a random access procedure at a later time may indicate this to the network. For example, some MTC devices may allow some delay when accessing the cellular network. The network may use this information to assign an “extended wait timer” to the relevant devices as part of a message that rejects the connection request (RRC Connection Reject message in case of LTE). Therefore, contention may be avoided by rejecting a request from such delay tolerant devices, and directing these devices to re-start the random access procedure at a later time. The disadvantages of this method may be that an unsuccessful random access is a pre-assumption for this method. In other words, resources are wasted before the method is usable. Further, additional delay is added to the random access procedure for delay tolerant devices. In addition, the number of random accesses is not reduced.

Another possible measure to reduce the chances of RACH contention in the above-mentioned situations may be to define different routing area boundaries (e.g. tracking area boundaries in an LTE cellular network), which may be assigned randomly to different devices. With this only a subset of the devices may need to perform a routing area update at the same location. The disadvantage of this method may be that a large number of devices may still perform a random access. In typical cases, the number of devices performing simultaneous random access may be reduced by a factor of 2 to 4, but assuming about 1000 devices involved in this scenario, the reduced number of 250 to 500 may be very large and will may lead to a RACH overload, and thus, contention. Further, the number of total random accesses is not reduced.

Whilst the number of devices needing to perform a random access procedure may be increasing, many devices (e.g. mobile terminals, for example UEs) may be equipped with several radio access technologies (RATs). For example, a UE may use a cellular technology to connect to a cellular network, e.g. GSM, UMTS, LTE, by using the licensed bands. In addition, the UE may use a license-free band of frequencies, e.g. short-range communications technology to get sporadic access to nearby devices and content, e.g. Bluetooth and Wi-Fi (e.g. IEEE 802.11). Some devices (e.g. a terminal) may allow relaying of data and/or messages, received from another device (e.g. another terminal) via a short-range communications technology (e.g. Wi-Fi), to the cellular network by using a cellular technology. Such devices may be called a “relay device”, and such networks of sporadically connected terminals and relay devices may be called “Opportunistic Networks”. In addition to the concept of opportunistic networks, methods may be developed (e.g. in studies at 3GPP) to enable a direct communication between a terminal and a relay device. Such direct communication methods between a terminal and a relay device may also be encompassed in the terms “license-free band of frequencies” and “short-range communications technology”.

In various examples presented in the following description, a terminal may use a short-range radio connection (on a license-free band of frequencies and/or a short-range communications technology) with a relay device to request for radio network resources from a cellular network. The terminal may proceed to establish a cellular network connection with the cellular network using the radio network resources assigned to it by the cellular network. The information about radio network resources assigned to the terminal by the cellular network may be received by the terminal directly from a base station of the cellular network and/or from the relay device.

An effect of the above may be at least one of:

1) Avoidance of a contention based random access procedure.

2) Avoidance of usage of a cellular air interface by the terminal for a connection setup between the terminal and a base station of a cellular network.

4) Reduction in the number of RACH contentions.

FIG. 3shows a terminal300including a generator302, a transmitter304, and a controller306. The terminal300may also include a receiver308.

The terminal300may include, or may be, a mobile terminal, such as, for example, a UE. The UE may be equipped with a SIM (Subscriber Identity Module), and the SIM may run on a UICC (Universal Integrated Circuit Card). For example, the terminal300may correspond to the terminal102shown inFIG. 1.

Each of the generator302, the transmitter304, the controller306and the receiver308may be implemented by means of a circuit. The word “circuit” is used herein to mean any kind of a logic implementing entity, which may be special purpose circuitry or processor executing software stored in a memory, firmware, or any combination thereof. Thus, in one or more examples, a “circuit” may be a hard-wired logic circuit or a programmable logic circuit such as a programmable processor, e.g. a microprocessor (e.g. a Complex Instruction Set Computer (CISC) processor or a Reduced Instruction Set Computer (RISC) processor). A “circuit” may also be a processor executing software, e.g. any kind of computer program, e.g. a computer program using a virtual machine code such as e.g. Java. Different circuits can thus also be implemented by the same component, e.g. by a processor executing two different programs.

The terminal300may be configured to support a plurality of RATs. In other words, the terminal300may be configured to operate in a plurality of radio networks, wherein each radio network is configured in accordance with the network architecture of a different RAT. Stated in yet another way, the terminal300may be configured to communicate, for example with other devices, using a plurality of RATs. The other devices may include other UEs, and/or one or more base stations (e.g. a base station configured according to the base stations106a,106b,106cshown inFIG. 1), and/or other devices configured to establish a communicative link with the terminal300.

The terminal300may be configured to communicate using a plurality of RATs by means of at least one of the transmitter304and the receiver308. The plurality of RATs may include at least one cellular network technology and at least one non-cellular radio technology. For example, the terminal300may be configured to operate in a cellular network and a non-cellular network.

Illustratively, the terminal300may be configured to communicate with other cellular network devices (e.g. other terminals and/or one or more base stations) within a cellular network. Therefore, the plurality of RATs may include at least one cellular network technology, such as, for example, at least one of LTE (Long Term Evolution) cellular network communications technology, UMTS (Universal Mobile Telecommunications System) cellular network communications technology, GSM (Global System for Mobile Communications) cellular network communications technology, CDMA2000 (Code Division Multiple Access) cellular network communications technology, or any other cellular network communications technology which may be known as such in the art.

Cellular network technologies may operate in a licensed band of frequencies. In other words, cellular network operators may require a license to provide cellular network services to subscribers and/or users. Accordingly, the at least one cellular network technology of the plurality of RATs may refer to radio communications technology that uses a licensed band of frequencies (e.g. using a GSM and/or a UMTS and/or a LTE band of frequencies).

As described above, the terminal300may be configured to additionally operate in a non-cellular network, namely, the terminal300may be configured to communicate with other devices (e.g. other terminals) using radio access technology other than cellular network technology. For example, the terminal300(e.g. a UE) may communicate (e.g. exchange data and/or content) with another UE using at least one of Wi-Fi radio technology, Bluetooth radio technology, Ultra-Wideband radio technology, Zigbee radio technology, or any other non-cellular radio technology which may be known as such in the art.

Non-cellular radio technologies may operate in a license-free band of frequencies. In other words, operators may not require a license to provide non-cellular radio services to subscribers and/or users. Accordingly, the at least one non-cellular radio technology of the plurality of RATs may refer to radio communications technology that uses a licensed-free band of frequencies (e.g. using a Wi-Fi and/or a Bluetooth and/or a Ultra-Wideband and/or a Zigbee band of frequencies).

Alternatively, or in addition to the above, non-cellular radio technologies may operate in a licensed frequency band. For example, non-cellular technology may be currently developed at 3GPP within the study item named “Feasibility Study for Proximity Services (ProSe)”. The outcome may be a new radio technology that may enable a direct communication between two devices by using licensed spectrum without using elements from a core network of the cellular radio network that uses the same frequency band, e.g. a eNB may not be required for this kind of communication. This potential new technology may be referred to as “LTE direct” and may be regarded as a non-cellular radio technology.

Non-cellular radio technologies may include, or may be, short-range communications technology. In other words, a node of a non-cellular radio network may provide a non-cellular radio connection to devices within a short distance from the node, for example within a distance of less than or equal to about 3 km from the node, for example less than or equal to about 2 km from the node, for example less than or equal to about 1 km from the node, for example, less than or equal to about 500 m from the node, for example less than or equal to about 300 m from the node, for example less than or equal to about 250 m from the node, for example less than or equal to about 200 m from the node, for example less than or equal to about 180 m from the node, for example less than or equal to about 150 m from the node, for example less than or equal to about 100 m from the node, for example less than or equal to about 80 m from the node, for example less than or equal to about 50 m from the node, for example less than or equal to about 30 m from the node, for example less than or equal to about 15 m from the node, for example less than or equal to about 10 m from the node, for example less than or equal to about 5 m from the node, for example less than or equal to about 1 m from the node, for example less than or equal to about 80 cm from the node, for example less than or equal to about 50 cm from the node, for example less than or equal to about 20 cm from the node, although other distances may be possible as well.

As shown inFIG. 3, the terminal300may include a generator302. The generator302may be configured to generate a request for radio network resources from a cellular network (e.g. the cellular network104shown inFIG. 1).

By way of an example, the request for radio network resources from the cellular network may include, or may be, a request for initial access to the cellular network, e.g. when the terminal300switches from the RRC_IDLE state to the RRC_CONNECTED state in an LTE cellular network. In another example, the request for radio network resources from the cellular network may include, or may be, a request for a time slot (e.g. a timing alignment value, a timing advance value) at which the terminal300may exchange data with a base station of the cellular network (e.g. a time slot at which terminal300may exchange user and/or control data with an eNB of an LTE cellular network). In yet another example, the request for radio network resources from the cellular network may include, or may be, a request for a frequency sub-band over which the terminal300may exchange data with a base station of the cellular network (e.g. a frequency sub-band with which terminal300may exchange user and/or control data with an eNB of an LTE cellular network). In some cases, the request for radio network resources from the cellular network may include, or may be, a request for an access code with which the terminal300may access a channel of the cellular network (e.g. a request for a dedicated RACH preamble, for example in non-contention based random access shown inFIG. 2B).

As shown inFIG. 3, the terminal300may include the transmitter304. The transmitter304may be configured to transmit the request for radio network resources, generated by the generator302, to at least one relay device. As described above, the terminal300may be configured to communicate with other devices using a plurality of RATs, and the plurality of RATs may include at least one non-cellular radio technology. The transmitter304may be configured to transmit the request for radio network resources to the at least one relay device using a non-cellular radio technology, for example using Wi-Fi and/or Bluetooth and/or Ultra-wideband and/or Zigbee and/or LTE-direct. The at least one relay device may be in close proximity to the terminal300(e.g. less than or equal to about 300 m), and is not shown inFIG. 3.

As shown inFIG. 3, the terminal300may include the receiver308. The receiver308may be configured to receive information about radio network resources assigned to the terminal300by the cellular network, which may be received from another device (e.g. another UE, and/or one or more base stations).

As shown inFIG. 3, the terminal300may include the controller306. The controller306may be configured to establish a cellular network connection between the terminal300and a base station (e.g. a NB and/or an eNB) of the cellular network (e.g. a GSM and/or UMTS and/or LTE communications system) using radio network resources (e.g. a time slot and/or a frequency sub-band and/or an access code) assigned to the terminal300by the cellular network.

FIG. 4shows a message flow400among a relay device402, a terminal404, and a base station406.

The message flow400illustrates that the terminal404may establish a cellular network connection420with the base station406of a cellular network using the relay device402, without having to perform a random access procedure with the base station406.

The relay device402may include, or may be, a mobile terminal, such as, for example, a UE (user equipment). The relay device402may be equipped with a SIM (Subscriber Identity Module), and the SIM may run on a UICC (Universal Integrated Circuit Card). Only one relay device402is shown as an example, however the number of relay devices may be greater than one, and may, for example, be two, three, four, five, six, seven, eight, nine, or on the order of tens, hundreds of, or even more relay devices.

The relay device402may be configured to support a plurality of RATs. In other words, the relay device402may be configured to communicate with other devices (e.g. UEs and/or one or more base stations) using a plurality of RATs.

The relay device402may be configured to communicate (e.g. exchange data and/or messages) with other devices (e.g. UEs and/or one or more base stations) using at least one cellular network technology (e.g. LTE and/or UMTS and/or GSM and/or CDMA2000). Accordingly, the plurality of RATs supported by the relay device402may include at least one cellular network technology (e.g. LTE and/or UMTS and/or GSM and/or CDMA2000).

The relay device402may also be configured to communicate (e.g. exchange data and/or messages) with other devices (e.g. UEs) using at least one non-cellular radio technology (e.g. a short-range communications technology and/or a radio technology that uses a license-free band of frequencies, for example Wi-Fi and/or Bluetooth). Accordingly, the plurality of RATs supported by the relay device402may further include at least one non-cellular radio technology (e.g. a short-range communications technology, for example Wi-Fi and/or Bluetooth).

The terminal404may be configured in a similar manner to the terminal300shown inFIG. 3. For example, the terminal404may include a generator (similar to generator302shown inFIG. 3), a transmitter (similar to transmitter304shown inFIG. 3), and a controller (similar to controller306shown inFIG. 3).

The terminal404may be configured to support a plurality of RATs. In other words, the terminal404may be configured to communicate with other devices (e.g. UEs and/or one or more base stations) using a plurality of RATs. Similarly to the relay device402, the plurality of RATs supported by the terminal404may include at least one cellular network technology (e.g. LTE and/or UMTS and/or GSM and/or CDMA2000) and at least one non-cellular radio technology (e.g. a short-range communications technology, for example Wi-Fi and/or Bluetooth).

The base station406may be a node of a cellular network. For example, the base station406may correspond to at least one of the base stations106a,106b,106cof the cellular network104shown inFIG. 1. For example, the base station406may be a node (e.g. a NodeB) of an UMTS cellular network. In another example, the base station406may be a node (e.g. an eNodeB) of an LTE cellular network. In yet another example, the base station406may be a node of a GSM cellular network. In some cases, the base station406may be a node of a plurality of cellular networks. For example, the base station406may be shared among a plurality of cellular network operators, e.g. shared among two or more PLMNs (Public Land Mobile Networks). Accordingly, devices (e.g. UEs) within a coverage area (e.g. a cell) of the base station406may be able to access two or more PLMNs using the base station406. Therefore, the base station406may be a base station of at least one cellular network (e.g. the base station406may be a NodeB of a GSM cellular network, and a eNodeB of an LTE cellular network).

The relay device402and the terminal404may be located within a cell served by the base station406(e.g. within the cell105bserved by the base station106bshown inFIG. 1). The relay device402may be connected to the base station406via a cellular network connection. In other words, the relay device402may have a cellular network connection established with the base station406. For example, the relay device402may be in an RRC_Connected state with respect to the base station406(e.g. an eNodeB) of an LTE cellular communications network. Therefore, the relay device402may not need to perform a random access procedure before data and/or messages are exchanged between the relay device402and the base station406.

Alternatively, the relay device402may be a device that may have a high priority of access with respect to the base station406. For example, the relay device402may be included in a list of priority-users of the base station406. Therefore, the relay device402may easily establish a cellular network connection with the base station406. For example, the relay device402may easily switch from a RRC_IDLE mode to a RRC_CONNECTED mode in an LTE cellular communications network.

The terminal404, in addition to being within the cell served by the base station406, may be in close proximity to the relay device402. For example, the terminal404may be within a coverage area of a non-cellular radio technology supported by the relay device402(e.g. a short-range communications technology, for example Wi-Fi and/or Bluetooth and/or Ultra-Wideband and/or Zigbee and/or LTE-direct). By way of another example, the terminal404and the relay device402may be separated from each other by a distance of less than or equal to about 300 m. Accordingly, the relay device402and the terminal404may be close enough to each other to establish a non-cellular radio connection (e.g. a Wi-Fi, Bluetooth, Zigbee or LTE direct connection).

The messages of the message flow400are described in the following.

As shown inFIG. 4, the message flow400may include a broadcast message408. The broadcast message408may be transmitted by the base station406to all devices (e.g. all UEs) located within a cell served by the base station406. For example, the broadcast message408may be a downlink (DL) transmission sent on a PBCH (Physical Broadcast Channel) to all devices (e.g. all UEs) located within the cell sewed by the base station406.

The area of coverage of the base station406may extend to an edge of at least one neighboring cell. Accordingly, the broadcast message408may be received by devices (e.g. UEs) located within at least one neighboring cell, which may be located near to an edge of the at least one neighboring cell.

The terminal404may be configured to measure a signal power of the broadcast message408. For example, the terminal404may be configured to measure the signal power of the DL transmission sent on the PBCH (Physical Broadcast Channel) by the base station406. The measured signal power of the broadcast message408may be used to adjust an uplink (UL) transmission from the terminal404to the base station406when the cellular network connection420is established between the terminal404and the base station406(see description below). Alternatively, or in addition to the above, the measured signal power of the broadcast message408may be reported by the terminal404to the base station406. The measured signal power reported to the base station406may be used by the base station406to adjust a subsequent DL transmission from the base station406to the relay device402and/or the terminal404(see description below).

The broadcast message408may include information about at least one potential relaying device within the cell served by the base station406. The relay device402may be selected from the at least one potential relaying device using information contained in the broadcast message408, namely using information about the at least one potential relaying device within the cell served by the base station406.

The broadcast message408may include information about an identity of the at least one potential relay device. For example, the identity of the at least one potential relay device may include a C-RNTI (Cell-Radio Network Temporary Identifier) and/or an IMSI (International Mobile Subscriber Identity) of each potential relaying device of the at least one potential relaying device.

The broadcast message408may include information about a position of the at least one potential relaying device. The terminal404may select the relay device402from the at least one potential relaying device based on the position. For example, the terminal404may select the potential relaying device closest to it as the relay device402.

The at least one potential relaying device may be registered with at least one cellular network (e.g. at least one PLMN) using and/or sharing the base station406. For example, a first potential relaying device within the cell served by the base station406may be registered with a first PLMN (e.g. a PLMN according to UMTS network technology), whilst a second potential relaying device within the cell served by the base station406may be registered with a second PLMN (e.g. a PLMN according to LTE network technology, or another PLMN according to UMTS network technology).

The broadcast message408may include information about at least one cellular network supported by the at least one potential relaying device. Information about the at least one cellular network may include information about the network configuration (e.g. GSM or UMTS or LTE or CDMA2000) of the at least one cellular network. The terminal404may select the relay device402from the at least one potential relaying device based on the network configuration of the cellular network that is supported by the at least one potential relaying device. For example, the terminal404may want to establish an LTE network connection with the base station406, and may choose a potential relaying device that supports such an LTE network connection as the relay device402.

The broadcast message408may include information about an identity of the at least one cellular network supported by the at least one potential relaying device. The identity of the at least one cellular network may include at least one of an MCC (Mobile Country Code), MNC (Mobile Network Code), and LAC (Location Area Code) of the at least one cellular network.

The at least one potential relaying device within the cell may be configured to communicate with other devices (e.g. other UEs) using at least one non-cellular radio technology (e.g. a short-range communications technology, for example Wi-Fi, Bluetooth, Ultra-Wideband, Zigbee or LTE-direct). For example, a first potential relaying device within the cell may be configured to support a Wi-Fi connection, whilst a second potential relaying device within the cell may be configured to support Wi-Fi and Bluetooth connections.

The broadcast message408may include information about the at least one non-cellular radio technology (e.g. a short-range communications technology, for example Wi-Fi, Bluetooth, Ultra-Wideband, Zigbee or LTE-direct) supported by each potential relaying device of the at least one potential relaying device. Information about the at least one non-cellular radio technology may include information about the configuration (e.g Wi-Fi and/or Bluetooth and/or Ultra-Wideband and/or Zigbee and/or LTE-direct) of the at least one non-cellular radio technology. The terminal404may select the relay device402from the at least one potential relaying device based on the configuration of the non-cellular radio technology supported by the at least one relaying device. For example, the terminal404may want to establish a Wi-Fi connection with the relay device402, and may choose a potential relaying device that supports such a Wi-Fi connection as the relay device402.

The broadcast message408may include information about an identity of the at least one non-cellular radio technology supported by each potential relaying device of the at least one potential relaying device. The identity of the at least one non-cellular radio technology may include an SSID (Service Set Identification) of the at least one non-cellular radio technology.

As described above, a cellular network connection may be established in at least the following events: initial access to a cellular network; connection re-establishment (e.g. after radio link failure); handover to another base station, downlink (DL) and/or uplink (UL) data synchronization; and positioning of a terminal. The at least one potential relaying device within the cell served by the base station406may be configured to be used as the relay device402for a particular event (e.g. initial access to a cellular network, connection re-establishment, handover, etc.). For example, a first potential relaying device may be configured to be used as the relay device402when initial access to the cellular network is desired by the terminal404, whilst another potential relaying device may be configured to be used as the relay device402when positioning is desired by the terminal404.

The broadcast message408may include information indicating which of the at least one potential relaying device may be used for a particular event (e.g. initial access to a cellular network, connection re-establishment, handover, etc.). In other words, each potential relaying device may be assigned for use in a particular event. The broadvase message408may include information indicating such an assignment. The terminal404may select the relay device402from the at least one potential relaying device based on the events supported by (e.g. assigned to) the at least one potential relaying device. For example, the terminal404may want to establish a cellular network connection for positioning purposes, and the terminal404may select a potential relaying device that supports positioning (e.g. assigned for use during positioning) as the relay device402.

In summary, the terminal404may receive the broadcast message408(e.g. a DL transmission) from the base station406, and may select the relay device402from at least one potential relaying device using the information contained in the broadcast message408.

As shown inFIG. 4, the terminal404may establish a non-cellular radio connection410(e.g. a Wi-Fi connection) with the relay device402(e.g. a potential relaying device selected as the relay device402). For example, the broadcast message408may include an SSID of the non-cellular radio connection (as described above), and the terminal404may use the SSID to establish the non-cellular radio connection410(e.g. a Wi-Fi connection) with the relay device402.

The message flow400may include a request for radio network resources from a cellular network (hereinafter referred to as connection request412). For example, the request412may be at least one of a request for initial access to the cellular network (e.g. a RRC Connection request), a request for a time slot to exchange data with the base station406(e.g. a timing alignment value and/or a timing advance value), and a request for a frequency sub-band to exchange data with the base station406.

The connection request412may be made for at least one of the following purposes: initial access to a cellular network, connection re-establishment (e.g. after radio link failure), handover to another base station, downlink (DL) and/or uplink (UL) data synchronization, and positioning. As described above, the terminal404may measure the signal power of the broadcast message408. The connection request412may include the measured signal power of the broadcast message408.

The terminal404may transmit the connection request412(e.g. a RRC Connection request) to the relay device402via the non-cellular radio connection410(e.g. Wi-Fi connection) established between the relay device402and the terminal404. The non-cellular radio connection410between the relay device402and the terminal404may be secured by encrypting data and/or messages exchanged between the relay device402and the terminal404. For example, the connection request412may be encrypted using credentials (e.g. using at least one secret key) stored in the SIM of at least one of the relay device402and the terminal404.

The connection request412(e.g. a RRC Connection request) may include an identity of the terminal404(e.g. a C-RNTI of the terminal404), and an identity (e.g. the MCC/II/INC/LAC) of cellular network from which radio network resources are requested. The connection request412may include a forwarding flag. The forwarding flag of the connection request412may be configured to indicate to the relay device402that the connection request412is to be forwarded to the cellular network indicated in the connection request412(e.g. the cellular network may be indicated by its MCC/MNC/LAC).

The relay device402may receive the connection request412(e.g. a RRC Connection request) from the terminal404, for example, by means of a receiver. The relay device402may read the information contained within the connection request412. For example, the relay device402may read the identity of the cellular network (e.g. MCC/MNC/LAC) included in the connection request412. Accordingly, the relay device402may forward (e.g by transmitting) the connection request412to the base station406of the cellular network identified in the connection request412as a forwarded request414, for example, by means of a transmitter. The forwarded request414may include an identity (e.g. C-RNTI) of the relay device402.

The relay device402may be connected to the cellular network identified in the connection request412via a cellular network connection (e.g. LTE network connection). Accordingly, the forwarded request414(e.g. a forwarded RRC Connection request) may be transmitted by the relay device402to the base station406of the cellular network via the cellular network connection (e.g. LTE network connection) established between the relay device402and the base station406.

Alternatively, the relay device402may be a device that may have a high priority of access with respect to the base station406. For example, the relay device402may easily establish a cellular network connection with at least one cellular network using the base station406, for example, the relay device402may easily switch from a RRC_IDLE mode to a RRC_CONNECTED mode in a LTE communications system. Accordingly, the forwarded request414(e.g. a forwarded RRC Connection request) may be transmitted by the relay device402to the base station406after the relay device402has established a cellular network connection between itself and the base station406of the cellular network identified in the request412.

As described above, the base station406may be shared among a plurality of PLMNs. Accordingly, the relay device402may transmit the forwarded request414to multiple PLMNs using the same base station406(e.g. the same eNB). Thereafter, the base station406may send the forwarded request414to the cellular network (or networks) identified in the connection request412and the forwarded request414.

The base station406may allocate radio network resources to the terminal404based on the forwarded request414. In other words, the base station406may select radio network resources for the terminal404. For example, the base station406may allocate a time slot (e.g. a timing alignment value and/or a timing advance value) and/or a frequency sub-band and/or an access code (e.g RACH preamble) to the terminal404. The base station406may provide information about the allocated radio network resources by transmitting a response416(e.g. a RRC Connection Setup message) to the relay device402using the cellular network connection (e.g. LTE network connection) established between the relay device402and the base station406. Accordingly, the relay device402may receive the response416, for example, by means of a receiver. The response416may include a tag, such as, for example, a forwarding flag configured to indicate to the relay device402that the response416is to be forwarded to the terminal404. Accordingly, the response416may include the identity (e.g. C-RNTI) of the terminal404. The response416may be a DL transmission from the base station406to the relay device402. The signal power of the DL transmission to the relay device402may be adjusted by the base station406based on the measured signal power of the broadcast message408included in the connection request412and the forwarded request414.

The relay device402may forward (e.g. by transmitting) the response416(e.g. RRC Connection Setup message) (e.g. by means of a transmitter), as a forwarded response418, to the terminal404using the non-cellular radio connection410(e.g. Wi-Fi and/or Bluetooth) established between the relay device402and the terminal404. Accordingly, the terminal404may be configured to receive (e.g. by means of a receiver) the forwarded response418from the relay device402. The forwarded response418may include a timing advance value used by the relay device402in the cellular network connection established between the relay device402and the base station406. For example, the timing advance value may be used by the relay device402to synchronize UL transmissions from the relay device402to the base station406. In like manner, the terminal404may use the timing advance value included in the forwarded response418to synchronize an UL transmission from itself to the base station406of the cellular network. The timing advance value included in the forwarded response418may be provided by either the base station406or the relay device402, or both. The timing advance value used by the relay device402may be suitable for synchronizing the UL transmission between the terminal404and the base station406since the relay device402and the terminal404may be in close proximity, e.g. since terminal404and relay device402may be connected to each other by a short-range communications technology, e.g. Wi-Fi and/or Bluetooth.

The terminal404may read the information included in the forwarded response418, and may use this information to establish a cellular network connection (e.g. a LTE network connection) with the base station406. For example, the terminal404may read the information about the radio network resources assigned to it by the cellular network, and may use the assigned radio network resources to establish the cellular network connection420with the base station406of the cellular network. By way of another example, the terminal404may use the timing advance value provided to it in the forwarded response418to adjust the timing of the UL transmission from the terminal404to the base station406. By way of yet another example, the terminal404may adjust the signal power of the UL transmission based on the measured signal power of the broadcast message408. The aforementioned examples are not mutually exclusive and may be carried out in combination with each other.

Therefore, the terminal404may establish a cellular network connection420(e.g. a LTE network connection) with the base station406without having to perform a random access procedure. A subsequent adjustment of the timing advance value may be possible after the cellular network connection420has been established between the terminal404and the base station406.

In summary, the following may be observed in message flow400:

1) The terminal404may detect potential relaying devices and select an appropriate one as the relay device402.

2) The terminal404may use the relay device402to request for radio network resources from a cellular network.

3) The relay device402may forward a request for radio network resources between the terminal404and the base station406of the cellular network from which the radio network resources are requested.

4) The base station406may receive a connection request412from the terminal404within a message (e.g. a forwarded request414) received from the relay device402.

5) The base station406may send a response (e.g. a Connection Setup message) to the terminal404within messages sent to the relay device402.

6) The terminal404may receive information about radio network resources allocated to it via the relay device402.

7) The relay device402may supply its currently used timing advance value to the terminal404.

8) The terminal404may use a timing advance value received from the relay device402to initially synchronise a UL transmission to a cellular network.

An effect of the message flow400ofFIG. 4may be at least one of the following:

1) Random access may be avoided for establishing a cellular network connection420between the terminal404and the cellular network (e.g. the base station406of the cellular network).

2) Calculation of a timing advance value may not be required since the timing advance value used by the relay device402may be forwarded to the terminal404in the response416and/or the forwarded response418. Use of the timing advance value used by the relay device402may be effective when a distance between the terminal404and the relay device402is small, for example less than or equal to about 100 m, for example less than or equal to about 80 m, for example less than or equal to about 50 m, for example less than or equal to about 30 m, for example less than or equal to about 15 m, for example less than or equal to about 10 m, for example less than or equal to about 5 m, for example less than or equal to about 1 m, for example less than or equal to about 80 cm, for example less than or equal to about 50 cm, for example less than or equal to about 20 cm, although other distances may be possible as well.

FIG. 5shows a message flow500among a relay device402, a terminal404, and a base station406including a response416sent from the base station406directly to the terminal404.

Reference signs inFIG. 5that are the same as inFIG. 4denote the same or similar elements as inFIG. 4. Thus, those elements will not be described in detail again here; reference is made to the description above. Differences betweenFIG. 5andFIG. 4are described below.

As described above, the relay device402may forward the connection request412to the base station406of the cellular network identified in the connection request412as the forwarded request414.

The base station406may select and/or allocate radio network resources to the terminal404based on the forwarded request414. For example, the base station406may allocate a time slot (e.g. a timing alignment value and/or a timing advance value) and/or a frequency sub-band and/or an access code (e.g RACH preamble) to the terminal404. The allocation of radio network resources to the terminal404by the base station406may be performed by means of an allocation circuit.

The base station406may provide information about the allocated radio network resources by transmitting a response506(e.g. a RRC Connection Setup message) to the terminal404, without using the relay device402as an intermediary device to forward the response506. For example, the response506may be sent to the terminal404as a downlink (DL) transmission to the terminal404. For example, the DL transmission may be sent on a PDSCH (Physical Downlink Shared Channel). Alternatively, the DL transmission may be sent on another DL resource, which may be indicated to the terminal404(see description below). Accordingly, the terminal404may be configured to receive (e.g. by means of a receiver) the response506from the base station406.

The signal power of the response506(e.g. DL transmission) to the terminal404may be adjusted by the base station406based on the measured signal power of the broadcast message408included in the request412and the forwarded request414. The response506may include an identity (e.g. C-RNTI) of the terminal404, which may indicate to the devices within the cell served by the base station406that the response506may be intended for the terminal404.

The response506may include a timing advance value used by the relay device402in the cellular network connection established between the relay device402and the base station406. As described above in relation to the response416and forwarded response418, the terminal404may use the timing advance value included in the response506to synchronize an UL transmission with the base station406of the cellular network.

As described above, the terminal404may read the information included in the response506, and may use this information to establish the cellular network connection420(e.g. a LTE network connection) with the base station406.

As described above, the response506may be sent to the terminal404as a DL transmission from the base station406to the terminal404. The DL resources with which the response506is transmitted from the base station406to the terminal404may be indicated as DL channel information502. The DL channel information502may be sent (e.g. transmitted) to the relay device402by a DL transmission from the base station406to the relay device402. Therefore, the relay device402may receive the DL channel information502from the base station406, for example, by means of a receiver. The channel information502may be sent to the relay device402before the response506is transmitted to the terminal404. As described above, the DL channel information502may include information about the DL resources (e.g. DL channel (e.g. frequency sub-band), DL access code, DL time-slot, etc.) which may carry the response506. The DL channel information502may include a forwarding flag configured to indicate to the relay device402that the DL channel information502is to be forwarded to the terminal404. The DL channel information502may include an identity (e.g. C-RNTI) of the terminal404. The relay device402may forward (e.g. by transmitting) the DL channel information502to the terminal404(e.g. by means of a transmitter) as forwarded DL channel information504. The terminal404may read the information contained in the forwarded DL channel information504, and may await transmission of the response506on the DL resource indicated in the forwarded DL channel information504.

Effects and observations related to the message flow400may be equally applicable to the message flow500ofFIG. 5. In addition, the following may be observed from the message flow500:

1) The base station406may send DL resource information to the terminal404via the relay device402. These DL resources may then be used by the base station406to send resource assignments directly to the terminal404.

2) The terminal404may be able to receive information about DL resources on which it may receive resources from the network directly.

FIG. 6shows a message flow600among a relay device402, a terminal404, and a base station406, wherein a non-contention random access preamble may be obtained by the terminal404through the relay device402.

Reference signs inFIG. 6that are the same as inFIG. 4denote the same or similar elements as inFIG. 4. Thus, those elements will not be described in detail again here; reference is made to the description above. Differences betweenFIG. 6andFIG. 4are described below.

As shown inFIG. 6, the message flow600may include the broadcast message408transmitted by the base station406to the terminal404.

Certain events (e.g. initial access to a cellular network, connection re-establishment, handover, etc.) may require a dedicated random access preamble in order for a cellular network connection to be established between the terminal404and the base station406. For example, as described above, handover to another base station, downlink (DL) data synchronization, and positioning may require a dedicated random access preamble. Accordingly, the broadcast message408may include, among other things described above, an instruction to the terminal404to request for a random access preamble when connection to the base station is desired for such events (e.g. handover, positioning).

The message flow600may be used when a random access preamble is required for the terminal404to establish a cellular connection with the base station406(e.g. in events such as handover, DL data synchronization, positioning, etc.).

As shown inFIG. 6, the terminal404may establish the non-cellular radio connection410(e.g. a Wi-Fi connection) with the relay device402using information contained in the broadcast message408.

The message flow600may include a request for RACH resources from a cellular network (hereinafter referred to as RACH resource request602). For example, the RACH resource request602may be a request for a dedicated random access preamble from the cellular network. As described above, the terminal404may measure the signal power of the broadcast message408. The RACH resource request602may include the measured signal power of the broadcast message408.

The terminal404may transmit the RACH resource request602(e.g. request for dedicated random access preamble) to the relay device402via the non-cellular radio connection410(e.g. Wi-Fi connection) established between the relay device402and the terminal404. The RACH resource request602transmitted from the terminal404to the relay device402may be encrypted using credentials (e.g. at least one secret key) stored on the SIM of at least one of the relay device402and the terminal404.

The RACH resource request602(e.g. dedicated preamble request) may include an identity (e.g. C-RNTI) of the terminal404, and an identity (e.g. MCC and/or MNC and/or LAC) of the cellular network from which radio network resources are requested. The RACH resource request602may include a forwarding flag. The forwarding flag of the RACH resource request602may be configured to indicate to the relay device402that the RACH resource request602is to be forwarded to the cellular network indicated in the RACH resource request602(e.g. the cellular network may be indicated by its MCC/MNC/LAC).

The relay device402may receive the RACH resource request602from the terminal404(e.g. by means of a receiver). The relay device402may read the information contained within the RACH resource request602. Accordingly, the relay device402may forward (e.g. by transmitting by means of a transmitter) the RACH resource request602to the base station406of the cellular network identified in the RACH resource request602(also referred to as the cellular network) as a forwarded RACH resource request604(hereinafter forwarded request604). The forwarded request604may include an identity (e.g. C-RNTI) of the relay device402.

As described above, the relay device402may be connected to the cellular network identified in the RACH resource request602via a cellular network connection (e.g. LTE network connection). Alternatively, as described above, the relay device402may be a device that may have a high priority of access with respect to the base station406.

The base station406may select and/or allocate a random access preamble to the terminal404based on the forwarded request604. The base station406may provide the allocated random access preamble to the terminal404by transmitting a RACH resource assignment606to the relay device402using the cellular network connection (e.g. LTE network connection) established between the relay device402and the base station406. The RACH resource assignment606may also include a frequency and a time slot (e.g. timing alignment value and/or timing advance value) for the terminal404to use the allocated random access preamble.

The base station406may start a timer upon transmission of the RACH resource assignment606to the relay device402. The timer may, for example, count down from a pre-determined value (e.g. 10 seconds, although other values are possible). The base station406may expect reception of the allocated random access preamble from the terminal404before expiration of the timer. The base station406may release the allocated random access preamble if the terminal404fails to transmit the preamble within the time allocated, and/or at the time slot indicated in the RACH resource assignment606. The pre-determined value of the timer may be included in the RACH resource assignment606. The predetermined value of the timer may be known by the terminal404(e.g. since it may be included in the RACH resource assignment606). Alternatively, the predetermined value of the timer may be a default value that may be pre-configured in the terminal404.

The RACH resource assignment606may include a tag, such as, for example, a forwarding flag configured to indicate to the relay device402that the RACH resource assignment606is to be forwarded to the terminal404. Accordingly, the RACH resource assignment606may include the identity (e.g. the C-RNTI) of the terminal404. The RACH resource assignment606may be a DL transmission from the base station406to the relay device402. The signal power of the DL transmission to the relay device402may be adjusted by the base station406based on the measured signal power of the broadcast message408included in the RACH resource request602and the forwarded request604.

The relay device402may forward the RACH resource assignment606, as a forwarded RACH resource assignment608, to the terminal404using the non-cellular radio connection410(e.g. Wi-Fi and/or Bluetooth) established between the relay device402and the terminal404. Accordingly, the terminal404may be configured to receive (e.g. by means of a receiver) the forwarded RACH resource assignment608from the relay device402.

The terminal404may read the information included in the forwarded RACH resource assignment608, and may use this information to start a non-contention random access procedure610to the base station406(see, for example,FIG. 2). Since the terminal404has received a dedicated random access preamble (included in forwarded RACH resource assignment608), request for such a preamble from the base station406may not be necessary. The non-contention random access procedure610may include transmission of the random access preamble by the terminal404to the base station406(e.g. corresponding to random access preamble208inFIG. 2), and a random access response message transmitted by the base station406to the terminal404(e.g. corresponding to Random Access Response210inFIG. 2). The random access response may include a resource assignment (e.g. time-slot and/or frequency sub-band and/or access code) for a subsequent UL transmission from the terminal404to the base station406.

The terminal404may establish a cellular network connection420with the base station406using information contained in the random access response included in the non-contention random access procedure610. For example, the terminal404may use the assigned time-slot (e.g. timing alignment value and/or timing advance value) and/or frequency sub-band and/or access code to transmit a “Connection Request” message to the base station406. The base station406may reply with a resource assignment for a UL-shared channel and/or DL-shared channel based on terminal's request, and a cellular network connection420may be established between the terminal404and the base station406.

Similar to the message flow inFIG. 5, the RACH resource assignment606may be provided directly to the terminal404by the base station406. Accordingly, DL resources with which the RACH resource assignment606is transmitted from the base station406directly to the terminal404may be indicated as DL channel information (e.g. as in DL channel information502inFIG. 5). The DL channel information may be sent to the relay device402and forwarded by the relay device402to the terminal404, before the RACH resource assignment606is transmitted from the base station406directly to the terminal404.

An effect of the message flow600may be at least one of the following:

1) Avoidance of contention-based random access for establishing a connection to a cellular network.

2) Accurate calculation of UL timing and/or UL transmit power required for establishing the cellular network connection420.

3) More precise timing advance value, since this may be provided by the base station406to the terminal404in the RACH resource assignment606.

FIG. 7shows a message flow700among a potential relaying device701, a terminal404, and a base station406, wherein the base station406instructs the terminal404to use the potential relaying device701to establish a cellular network connection.

Only potential relaying device701is shown as an example, however the number of potential relaying devices may be greater than one, and may, for example, be two, three, four, five, six, seven, eight, nine, or on the order of tens, hundreds of, or even more potential relaying devices.

Reference signs inFIG. 7that are the same as inFIG. 4denote the same or similar elements as inFIG. 4. Thus, those elements will not be described in detail again here; reference is made to the description above. Differences betweenFIG. 7andFIG. 4are described below.

The base station406may detect the need to reduce the usage of contention based random access. For example, the base station406may expect a RACH overload (e.g. the base station406may detect that there may be more terminals than the number of available RACH preambles). By way of another example, the base station406may plan to reduce the RACH resources (e.g. reduce the available time slots and/or frequency bands and/or access codes for RACH access) in order to use them for at least one UL shared channel.

Alternatively, or in addition to the above, the base station406may detect the opportunity to use a potential relaying device701(e.g. by means of a detection circuit). For example, at least one potential relaying device701may be detected in the cell served by the base station406and/or the at least one potential relaying device701may offer to act as an intermediary device (e.g. a beacon) to relay messages to the base station406(see description below in relation toFIG. 8).

Detecting the need to reduce the usage of contention based random access and/or detecting the opportunity to use a relay device (e.g. by means of a detection circuit) may trigger a service redirection requirement702in the base station406. A service may refer to either one of a connection request (e.g. in respect ofFIG. 4andFIG. 5) or a request for a RACH preamble (e.g. in respect ofFIG. 6). In other words, the base station406may detect the need to redirect a connection request and/or request for a RACH preamble in order to avoid contention, collision and/or RACH overload. The base station406may select which service to redirect. For example, the base station406may determine that connection requests may need to be requested through a potential relaying device701in order to avoid contention, collision and/or RACH overload. Alternatively, or in addition to the above, the base station406may determine that RACH preamble requests may need to be requested through a potential relaying device701in order to avoid contention, collision and/or RACH overload.

The base station406may assign at least one service to each potential relaying device. The assignment of a service to a potential relaying device may depend on signal quality of a cellular connection between the base station406and the potential relaying device, remaining battery capacity of the potential relaying device, etc.

The assignment of the at least one service to each potential relaying device701may be included in a service setup instruction704. The service setup instruction704may be generated by the base station406(e.g by means of a generator, which may be implemented as a circuit). The service setup instruction704may be transmitted by the base station406(e.g. by means of a transmitter) to the potential relaying device701. Accordingly, the potential relaying device701may receive the service setup instruction704from the base station406, e.g. by means of a receiver. The service setup instruction704may be used by the potential relaying device701to configuring its forwarding capability. For example, the service setup instruction704may include the type of service to be setup (e.g. connection request and/or random access preamble request). The service setup instruction704may include policies that may restrict the usage of each service type to certain events. In other words, the service setup instruction704may indicate which events may use a particular service. For example, random access preamble request may be used for only position, whilst connection request may be used for initial access to a cellular network, e.g. initial access from RRC_IDLE state.

The service setup instruction704may include information about the connection between the potential relaying device701and the base station406. For example, this may include routing instructions for messages exchanged between the terminal404and the base station406, through the potential relaying device701.

The potential relaying device701may apply the service setup instruction704, and may await a service request from the terminal404(indicated as706inFIG. 7).

The base station406may broadcast system information to the terminal404that may include a redirection instruction708. Accordingly, the redirection instruction708may correspond to the broadcast message408inFIG. 4toFIG. 6. Accordingly, the terminal404may be configured to receive (e.g. by means of a receiver) the redirection instruction708from the base station406.

The redirection instruction708may include an instruction to the terminal404to use the potential relaying device701as an intermediary device for a connection request and/or random access preamble request. The redirection instruction708may include information which services (e.g. a connection request and/or random access preamble request) may be used for the potential relaying device701.

The redirection instruction708may include an indication that the potential relaying device701may be present in the cell served by the base station406(or in a neighboring cell of the base station406). The redirection instruction708may include an identity (e.g. C-RNTI) of the potential relaying device701. The redirection instruction708may include information about a position of the potential relaying device701. The redirection instruction708may include information (e.g. network configuration and/or identity, for example MCC/MNC/LAC) about at least one cellular network that may be registered with the potential relaying device701. The redirection instruction708may also include information (e.g. configuration and/or identity, for example SSID) about the at least one non-cellular radio technology supported by the potential relaying device701.

The terminal404may apply the received redirection instruction708(indicated as710inFIG. 7). For example, the terminal404may need to perform positioning, and may select a potential relaying device701which may support positioning as the relay device402shown inFIG. 4toFIG. 6. Thereafter, the message flow700may proceed in the manner of either one ofFIG. 4,FIG. 5, orFIG. 6.

In summary, the following may be observed from the message flow700ofFIG. 7:

1) The base station406of the cellular network may detect the need and/or the opportunity to redirect at least one service.

2) The base station406may instruct the potential relaying device701to offer a redirection service and may supply configuration parameters to the potential relaying device701.

3) The base station406may instruct the terminal404to use a redirection service.

4) The terminal404may be given information (e.g. configuration parameters) by the base station406that may be used to select a relay device402from the at least one potential relaying devices701.

An effect of the message flow700ofFIG. 7may be at least one of the following:

1) Reduced usage of RACH resources.

2) The base station406may have control of over the setup of the potential relaying device701.

3) The base station406may instruct the terminal404to use a service via the potential relaying device701.

4) A user may experience a low delay during connection setup due to a lower number of rejected connection requests since RACH overload may be avoided.

FIG. 8shows a message flow800among a potential relaying device701, a terminal404, and a base station406, wherein the potential relaying device701advertises its services to the terminal404and the base station406.

Reference signs inFIG. 8that are the same as inFIG. 4andFIG. 7denote the same or similar elements as inFIG. 4andFIG. 7. Thus, those elements will not be described in detail again here; reference is made to the description above. Differences betweenFIG. 8andFIGS. 4 and 7are described below.

The message flow800may be used in cases where a RACH overload may be foreseen by the terminal404and the detection by the base station406may be too late or inexact.

The potential relaying device701may establish a cellular network connection802(e.g. LTE network connection) with the base station406.

The potential relaying device701may choose to act as an intermediary device for messages between the terminal404and the base station406. Accordingly, the potential relaying device701may send this information to the base station406as a redirection service information804. The redirection service information804may include information about the availability (i.e. willingness and/or capability) of the potential relaying device701as an intermediary device for terminals within the cell served by the base station406. Stated differently, the redirection service information804may be a message that may include information indicating the availability (i.e. willingness and/or capability) of the potential relaying device701to forward (e.g by transmitting by means of a transmitter) a request for radio network resources from the terminal404to the base station406of a cellular network. The potential relaying device701may receive a control message (not shown inFIG. 8) from the base station406. The control message may include configuration parameters. For example, the potential relaying device701may use the control message to set up the redirection service for the terminal404.

The potential relaying device701may thereafter be ready for the redirection service and may await for requests (e.g. connection requests and/or random access preamble requests) from the terminal404.

The potential relaying device701may transmit, periodically, a redirection service advertisement806. The redirection service advertisement806may indicate to a terminal404the availability (i.e. willingness and/or capability) of the potential relaying device701to forward (e.g by transmitting by means of a transmitter) a request for radio network resources from the terminal404(e.g. a UE) to the base station406of a cellular network. The potential relaying device701may broadcast this redirection service advertisement806via a short-range communications technology (e.g. Wi-Fi connection). The redirection service advertisement806may be transmitted on the short-range communications technology as a broadcast message (e.g. a beacon message), or as a dedicated message to the terminal404. Accordingly, the terminal404may be configured to receive (e.g. by means of a receiver) the redirection service advertisement806from the potential relaying device701.

The redirection service advertisement806may include an identity of the connected cellular network (e.g. the identity of the cellular network of the connection802). For example, the identity of the connected cellular network may be a MCC/MNC/LAC of the cellular network using and/or sharing the base station406. The redirection service advertisement806may also include information about the type of redirection services the potential relaying device701may be capable of. For example, the redirection service advertisement806may indicate that the potential relaying device701may be used for a connection request and/or a random access preamble request.

The terminal404may read the redirection service advertisement806and may want to connect to a cellular network. The terminal404may first scan for the availability of the network (indicated as808inFIG. 8). If the network is available, the terminal404may scan for the periodically advertised redirection service810on the short-range communications technology (e.g. Wi-Fi connection). The terminal404may decide to use the redirection service offered by the potential relaying device701instead of performing a contention based random access procedure with the cellular network. The terminal404may decide to use the redirection service based on a signal quality of the potential relaying device701and/or because the potential relaying device701may be preferred by the user and/or the cellular network operator to use this service. The terminal404may then select the potential relaying device701as the relay device402shown inFIG. 4toFIG. 6. Thereafter, the message flow800may proceed in the manner of either one ofFIG. 4,FIG. 5, orFIG. 6.

In summary, the following may be observed from the message flow800:

1) The potential relaying device701may inform the base station of the cellular network that it may be capable of redirection, and may negotiate the usage and/or parameters with the base station406.

2) The potential relaying device701may advertise its capability to provide at least one service (eg, connection requests and/or random access preamble requests) via its short-range communications technology (e.g. Wi-Fi) to the terminal404.

An effect of the message flow800may be at least one of:

1) Enabling a redirection service even in the case when the cellular network has not detected the need or the opportunity to do so.

2) Faster decision about the need and/or the opportunity for using a redirection service.

FIG. 9shows a method900for establishing a cellular network connection between a terminal and a base station.

The method900may include: generating a request for radio network resources from a cellular network (in902); transmitting the request for radio network resources to a relay device, wherein the request for radio network resources may be configured to be forwarded by the relay device to the base station of the cellular network (in904); and establishing a cellular network connection between the terminal and the base station of the cellular network using radio network resources assigned to the terminal by the cellular network (in906).

The features of the message flows shown inFIG. 4toFIG. 8may be applicable to method900shown inFIG. 9.

According to various examples described herein, a terminal may be provided. The terminal may include a generator configured to generate a request for radio network resources from a cellular network; a transmitter configured to transmit the request for radio network resources to a relay device, wherein the request for radio network resources may be configured to be forwarded by the relay device to a base station of the cellular network; and a controller configured to establish a cellular network connection between the terminal and the base station of the cellular network using radio network resources assigned to the terminal by the cellular network.

The request for radio network resources may include a request for a time slot for a transmission from the terminal to the base station of the cellular network.

The request for radio network resources may include a request for a frequency sub-band for a transmission from the terminal to the base station of the cellular network.

The request for radio network resources may include a request for an access code for a channel between the terminal and the base station of the cellular network.

The request for radio network resources may include a request for a random access preamble from the cellular network.

The request for radio network resources may include an identity of the terminal; and an identity of the cellular network.

The request for radio network resources may include an identity of the relay device.

The request for radio network resources may include a forwarding flag for indicating to the relay device that the request for radio network resources may need to be forwarded to the base station of the cellular network.

The request for radio network resources may include a radio resource control (RRC) connection request.

The request for radio network resources may include: a request for a dedicated random access channel (RACH) preamble.

The transmitter may be configured to transmit the request for radio network resources to the relay device according to a short-range communications technology.

The short-range communications technology may include at least one of Wi-Fi, Bluetooth, Ultra-Wideband, and ZigBee.

The request for radio network resources may be configured to be forwarded by the relay device to the base station using a cellular radio communications technology.

The cellular radio communications technology may include at least one of LTE, UMTS, GSM, and CDMA2000.

The terminal may further include a receiver configured to receive a message from at least one of the base station and the relay device.

The message from the relay device may include information about radio network resources assigned to the terminal by the cellular network.

The message from the relay device may include a timing advance value for an uplink transmission from the terminal to the base station.

The message from the base station may include information about radio network resources assigned to the terminal by the cellular network.

The message from the base station may include an instruction to use at least one potential relaying device as the relay device.

The message from the base station may include information for selecting the relay device from at least one potential relaying device.

The information for selecting the relay device from the at least one potential relaying device may include a position of the at least one potential relaying device; and an identity of at least one radio access technology supported by the at least one potential relaying device.

The identity of at least one radio access technology may include a service set identifier (SSID) of at least one short-range communications technology supported by the at least one potential relaying device.

The identity of at least one radio access technology may include at least one of a Mobile Country Code (MCC), Mobile Network Code (MNC), and Location Area Code (LAC) of at least one cellular radio communications technology supported by the at least one potential relaying device.

The information for selecting the relay device from the at least one potential relaying device may include an indication of a redirection service offered by the at least one potential relaying device.

According to various examples described herein, a relay device may be provided. The relay device may include a transmitter configured to transmit a message indicating an availability of the relay device to forward a request for radio network resources from a cellular network by a terminal to a base station of the cellular network.

The transmitter may further be configured to forward the request for radio network resources from the cellular network by the terminal to the base station of the cellular network.

The relay device may further include a receiver configured to receive, from the terminal, the request for radio network resources from the cellular network.

The receiver may be further configured to receive a control message from the base station of the cellular network, wherein the control message may be used by the relay device to set up a redirection service.

According to various examples described herein, a base station may be provided. The base station may include a detection circuit configured to detect an opportunity to use a relay device to forward a request for radio network resources from a cellular network by a terminal to the base station; a generator configured to generate a service setup instruction for configuring the forwarding capability of the relay device; and a transmitter configured to transmit the service setup instruction to the relay device.

According to various examples described herein, a method for establishing a cellular network connection between a terminal and a base station may be provided. The method may include generating a request for radio network resources from a cellular network; transmitting the request for radio network resources to a relay device, wherein the request for radio network resources may be configured to be forwarded by the relay device to the base station of the cellular network; and establishing a cellular network connection between the terminal and the base station of the cellular network using radio network resources assigned to the terminal by the cellular network.