GB2487905A - Mobile communications system using shortened terminal identifiers - Google Patents

Abstract

In a mobile communications system comprising mobile terminals and a base station, the base station sends super-frames comprising shared data communication channels and a control channel for resource allocation messages. Each terminal is allocated an identifier so that it can determine its resource allocation from the control channel messages. The base station is adapted to also send shorter identifiers for each terminal, related to the original identifiers, which the terminals also use to determine their resource allocation.. The shorter identifiers allow the allocation of more resources per super-frame to user terminals as more identifiers can be fitted in the control channel information in the super-fram. The mobile terminals may be organised in groups and receive respective super-frames for their group.

Description

I

MOBILE COMMUNICATIONS SYSTEM AND METHOD

Field of the Invention

The present invention relates to mobile communications systems for communicating data to and/or from mobile communications devices, infrastructure equipment, mobile communications devices and methods for communicating data packets.

Background of the invention

Mobile communication systems have evolved over the past ten years or so from the GSM System (Global System for Mobiles) to the 30 system and now include packet data communications as well as circuit switched communications. The third generation project partnership (3GPP) has now began to develop a mobile communication system referred to as Long Term Evolution (LTE) in which a core network part has been evolved to form a more simplified architecture based on a merging of components of earlier mobile communications network architectures and a radio access interface which is based on Orthogonal Frequency Division Multiplexing (OFDM) on the downlink and Single Carrier Frequency Division Multiple Access (SC-FDMA) on the uplink. The core network components are arranged to communicate data packets in accordance with an enhanced packet communications system.

At present mobile communications services are dominated by human to human (H2H) communications, that is, data which is transmitted by a human to another human or at least data that is transmitted for presentation to a human being. It is now recognised that there is a desire to cater for communications to andlor from machines which are referred to generally as machine type communications (MTC) or machine to machine (M2M) communications.

MTC communications can be characterised as communicating data which has been generated from a source automatically, for example in response to some other stimulus, or event reporting some attribute of the machine, or some monitored parameter, or so-called smart metering. Thus whilst human communications such as voice can be characterised as being communications requiring a communications session of some minutes with data being generated in bursts of several millisecond with pauses there between or video can be characterised as streaming data at a substantially constant bit rate, MIC communications can generally be characterised as sporadically communicating small quantities of data although it would be appreciated that there is also a wide variety of possible MIC communications.

As will be appreciated it is generally desirable to provide a mobile communications system and network which can operate efficiently, particularly although not exclusively in respect of the challenges presented by communicating data packets generated by MIC communications devices.

Summa!ypf the Inve ntioq According to the present invention there is provided a mobile communications system for communicating data to and/or from mobile terminals. The mobile communications system comprises a base station which includes a transmitter and a receiver which are arranged in operation to provide a wireless access interface for communicating the data to and/or from the mobile terminals and a scheduler for allocating communications resources of the wireless access interface to the mobile terminals for communicating the data. The wireless access interface provides a down-link frequency channel for communicating data to the mobile terminals and a shared control channel. The down-link frequency channel is divided in time into different units of communications resource which are allocated by the scheduler of the base station to.the mobile terminals. The time divided units may be for example sub-frames formed by dividing in time repeating time frames of the down-link frequency channel. The shared control channel communicates resource allocation messages to the mobile terminals, each resource allocation message including an identification number allocated to one of the mobile terminals for indicating an allocation of one of the units of communications resource of the wireless access interface. Each of a plurality of the mobile terminals is divided into a plurality of different groups, and the base station is adapted to form super-frames comprising a plurality of the units of communications resource of the down-link channel, to transmit in a first of the super-frames control information providing for each of the plurality of mobile terminals in a first of the groups of devices a short identification number in association with the identification number allocated to the mobile terminal by the base station for use in allocating the units of communications resource to the mobile terminal for the first super-frame, and to transmit in a second of the super-frames control information providing for each of the plurality of mobile terminals in a second of the groups of terminals a short identification number in association with the identification number allocated to the mobile terminal by the base station for use in allocating the units of communications resource to the mobile terminal for the second super-frame, and to adapt each of the resource allocation messages to include a plurality of the short identification numbers when allocating the units of communications resources to a plurality of the mobile terminals in the first or the second super-frames.

Embodiments of the present invention can provide a mobile communications system in which an arrangement is provided for reducing the size of resource allocation messages, which allocate resources of a shared channel to mobile communications devices for communicating data. As a result, the number of allocation messages which can be communicated via a shared down-link control channel can be increased which, in turn, increases a rate at which resources can be allocated for transmitting data to terminals. The reduction in the size of the resource allocation messages is achieved by allocating shortened identifiers to mobile terminals on a basis of a super-frame. The mobile terminals are divided into different groups and for each super-frame a short identifier is allocated to each of the mobile terminals of one of the groups in association with an identification number which is conventionally used and allocated to the mobile terminals for allocating resources. Thus for the duration of the super-frame the short identifiers can be used to allocate resources to the mobile terminals of the group. In the next frame the short identifiers are allocated to a different group of mobile terminals. Thus the same short identifier can be used between super frames but allocated to different mobile terminals, so that the short identifier can be a small quantity of data such as a few bits and smaller than the identification number. In one example the different groups are mutually exclusive so that one mobile terminal is allocated to one group only, but in other examples a mobile terminal may be allocated to more than one group.

The super-frame is comprised of a plurality of units of resource, which are formed by dividing a repeating frame in time, which may be equal time divisions. In one example, the units are sub-frames of a frame, so that the super-frame is formed from a repeating set of sub-frames, which may be greater than the frame, As will be appreciated, if a mobile terminal belongs to a group which has not been allocated a short identifier for the current super-frame then it may have to wait longer before communications resources can be allocated to it. However, the base station may have some time critical data to be communicated to that mobile terminal. Accordingly, in some examples, the base station may communicate a resource allocation message to a mobile terminal via the shared control channel, when the mobile terminal has not been allocated a short identifier for a current super frame, in which the resource allocation message includes an identification number of the mobile terminal.

According to some embodiments the identification number which is replaced by the short identifier in the resource allocation messages is a radio network temporary identifier or the like.

Further aspects and features of the present invention are defined in the appended claims and include an infra-structure element, a mobile terminal and methods.

Brief Description of the Q!aW!!!RS

Example embodiments of the present invention will now be described with reference to the accompanying drawings in which like parts have the same designated references and in which: Figure 1 is a schematic block diagram of a mobile communications network and mobile communications devices forming a communication system which operates in accordance with the 3GPP Long Term Evolution (LTE) standard; Figure 2 is a schematic representation of a down-link frequency carrier comprising sub-frames; Figure 3 is a schematic representation of a mobile network with up-link and down-link communications; Figure 4 is a schematic representation of a downlink frame comprising 6 sub-frames; Figure 5 is a simplified call-flow showing the RNTI allocation during an RRC connection setup; Figure 6 is a schematic representation of a super-frame according to an embodiment of the invention; Figure 7 is a schematic representation of two super-frames according to another embodiment of the invention; Figures 8a to Sc are examples of mapping or correspondence between RNTI5 and short-lDs; Figure 9 is a schematic representation of a downlink message translation process from RNTI to Short-ID; Figure 10 is an example of a super-frame comprising 3 sub-frames according to a further embodiment of the invention.

Descriptkrjpf Examp!trnbodhejit Embodiments of the present invention will now be described with reference to an implementation which uses a mobile communications network operating in accordance with the 3GPP Long Term Evolution (LIE) standard. Figure 1 provides the example architecture of an LIE network. As shown in Figure 1 and as with a conventional mobile communications network, mobile communications devices (also called UEs or terminals) I are arranged to communicate data to and from base stations 2 which are referred to in LIE as enhanced NodeBs (e-Nodel3). For transmitting and receiving data via the wireess access interface the communications devices 1 each include a transmitter/receiver unit 3.

The base stations or e-NodeB's 2 are connected to a serving gateway S-GW 6 which is arranged to perform routing and management of mobile communications services to the communications devices I as they roam throughout the mobile communications network. In order to maintain mobility management and connectivity, a mobility management entity (MME) 8 manages the enhanced packet service (EPS) connections with the communications devices I using subscriber information stored in a home subscriber server (HSS) 10. Other core network components include the policy charging and resource function (PCRF) 12 a packet data gateway (P-GW) 14 which connects to an internet network 16 and finally to an external server 20. More information may be gathered for the LTE architecture from the book entitled 1LTE for UMTS OFDM and SC-FDMA based radio access", Holma H. and Toskala A. page 25 if.

In the following description LTE/SAE terminology and names are used. However embodiments of the present technique can be applied to other mobile communications systems such as UMTS and GERAN with the GSM/GPRS core network.

LTE and RNTI allocation According to the LTE standard, communications are arranged in packet switched form in that a physical channel on the up-link and the down-link is not allocated to a communications device. Communications resources on both the up-link and the down-link for transmitting data are shared amongst all of the communications devices. On the up-link data is transmitted in physical up-link shared channels (PUSCH) whereas the down-link data is transmitted to the mobile communications devices on physical down-link shared channels (PDSCH). The allocation of resources on the up-and down-link shared channels is managed by the eNode B using a physical down-link control channel (PDCCH). If data is to be transmitted to a particular mobile communications device then the eNode B transmits a message on the down-link shared control channel which all of the mobile communications devices listen to. The mobile communications device to which the data is to be transmitted is identified using an identifier called Radio Network Temporary Identifier (RNTI). There are various types of RNTI allocated to mobile communications devices in accordance with a relative phase of a communication session in which data is communicated to or from the mobile communications device. Thus the eNode B transmits a message in the physical down-link control channel providing the RNTI of the mobile communications device (or devices) which is to receive data on the down-link and an indication of the down-link communications resources that have been allocated on the down-link shared channel to the mobile communications device(s). In Lit, RNTIs either uniquely identify a mobile communications device within a cell, like a C-RNTI which is used for example to send downlink data to one specific mobile communications device only, or they identify all the mobile communications devices in the cell. For example, a Sl-RNTI is used to send downlink data to all the mobile communications devices in the cell.

An example of a down-link arrangement of the physical down-link shared channels and the physical down-link control channel is shown in Figure 2. As explained above mobile communications devices are arranged to communicate via a base station or e-NodeB 2, using up-link and down-link shared communications resources. Thus, as shown in Figure 3, a plurality of mobile communications devices I communicate via an e-NodeB 2. Thus Figure 3 provides a simplified representation of a group of mobile communications devices which are operating within a cell served by the e-NodeB 2. As will be appreciated therefore the mobile communications devices must be allocated resources on the down-link shared channels in order to receive data from the base station.

As will be appreciated the down-link channel illustration provided by Figure 2 is in a somewhat simplified form. According to the LTE standard, a physical down-link frame is illustrated in Figure 4. Likewise, Figure 4 is a somewhat simplified form, for example a LTE frame usually includes 10 sub-frames but only 6 sub-frames have been represented for the downlink frame of Figure 4. In Figure 4 the PDCCH is shown which occupies some time and frequency resources within a resource zone that stretches across the entire frequency band and across I to 3 symbols, where the time and frequency resources are usually distributed within that zone based on a random or pseudo-random algorithm. In contrast the Physical Down-link Shared CHannel (PDSCH) is comprised of a plurality of time and frequency resources which are allocated via the PDCCH. In effect, the PDCCH provides the mobile communications devices with the resource allocations and the corresponding RNTI. A mobile communications device can therefore, based on the RNTI, know which resource allocations it should decode to receive its data. The data may be either data for this mobile communications device only or for all mobile communications devices in the cell.

A message sequence flow showing an exchange of messages which are required in order to allocate resources on the down-link as well as the up-link as shown in Figure 5. In Figure 5 a terminal I is shown communicating messages to and receive messages from an e-NodeB 2 when setting up a connection with the e-Nodel3 2 The first message MI is a message from the terminal I to the e-NodeB 2 which comprises RACH message including a RACH preamble. From the RACH preamble, a RA-RNTI (1Random Access RNTV') can be identified. The e-NodeB 2 then responds to the terminal I with message M2, sent to the RA-RNTI identified from the RACH preamble and comprising in particular a T-RNTI ("Temporary RNTI") and an uplink resource allocation.

The terminal 1 sends message M3 using the uplink resource allocated indicated in message M2, where the message is a RRG connection request sent as coming from the terminal with the T-RNTI indicated in message M2. The e-NodeB 2 responds to message M3 with a RRC connection setup message M4. M4 is sent to the T-RNTI of messages M2 and M3 and comprise the C-RNTI that the terminal I will use for the duration of the RRC connection. In effect, the C-RNTI is usually the same as the T-RNTI. In other words, once the RRC connection setup is successfully completed, the T-RNTI becomes the C-RNTI.

The usually way for a terminal I to receive data once the RRG connection has been successfully established is shown with in Figure 5. The terminal I will receive a downlink data on a downlink shared frequency channel of the type shown in Figure 4, i.e. including a PDCCH and a P08GW. The PDGGH will indicate in particular the resource allocation in the P08CM using the RNTI. For example the C-RNTI x is given the resources allocation A, the C-RNTI y is given the resource allocation 4 and the Sl-RNTI (for sending system information to the entire cell) is given the resource allocation A31. Then, based on the RNTIs in the PDCCH, the terminal I knows which resource elements to decode in the PDSCH. If for example the terminal 1 has the C-RNTI x, terminal I then decodes the data that has been allocated A (which is transmitted for this terminal only) and the data that has been allocated A3, (which is transmitted for all terminals in the cell). Terminal I will for example not decode the data that has been allocated 4 because the G-RNTI y does not indicate that the data is for terminal I, As can be seen in this example, the terminal I may decode data for several RNTIs, in this case G-RNTI x and Sl-RNT1. In another example, the terminal I may have more than one C-RNTI identifying it. For example, the data in allocation A and 4, may be for the same terminal I if terminal I can be identified as C-RNTI x and C-RNTI y. for information, various examples of RNTI types are provided in a table in the appended Annex.

Using this RNTI identification system, a downlink carrier can easily be shared amongst several terminals where each terminal knows where to find its data based on the RNTI associated with this data.

As will be appreciated from the above explanation in order to receive an allocation of resource then a mobile communications device must be explicitly identified using one of its RNTIs. In an MTC or dedicated messaging network, terminals which are operating as MTC type devices may be required to communicate a plurality of signalling messages in order to transmit a data message. In one example, in order to transmit for example a meter reading, a terminal will be required to exchange a series of messages via and/or to the base station which may include: -RRC connection -Authentication via a remote authentication server Session start with meter reading server -Meter reading data transfer which may also include an exchange of messages associated with the data transmission -Session with meter reading server tear down -RRcconnectionteardown.

In an LTE Network these messages are scheduled in the down-link using the PDCCH which communicates an allocation message to the terminals. The LIE standard defines that the PDCCH is to be sent in the control region at the beginning of each sub-frame, where the control portion is between I and 3 symbols long. The size of the control region is limited, thereby limiting the resources that can be allocated to PDCCH messages. Thus, when there are many small messages to be transmitted such as for example, short signalling messages, system capacity may be limited by the amount of available signalling resource which would be the number of PDCCHs available for an LTE network. Therefore the amount of data that can be transmitted to terminals is not in that case limited by the actual down-link capacity (e.g. the number of PDSCH), but by the capacity to signal those PDSCHS using PDCGHS.

According to the present technique an arrangement is provided for reducing the size of the allocation message to mobile communications devices for communicating data. As a result, the number of allocation messages which can be communicated via for example a PDCCH can be increased which, in turn, increases the resources allocated for transmitting data to terminals. In other words the number of PDCCHs per sub-frame can thereby be increased.

Sqper4ramejpmiat According to the present technique there is provided a super-frame structure, the super-frame comprising a plurality of down-link sub-frames, where some terminals are provided with a short identifier which can be used within the super-frame1 for example for allocating communications resources on a downlink shared channel.

In one example, the super-frame could be the duration of an LTE frame which is ten sub-frames or ten milliseconds or, in another example, it might be a multiple of the LIE frame duration. Figure 6 provides an example arrangement of a down-link frame structure illustrating a super-frame, where the super-frame is 10 sub-frames long. In Figure 6, a first frame structure 101 is shown to be comprised of a plurality of sub-frames 102. In an expanded form of a super-frame 104, it can be seen that the super-frame is comprised of a number of sub-frames. Each sub-frame includes a PDCCHs as well as a PDSCHs where the PDCCHs can be found in the PDCCH region and the PDSCHs in the PDSCH region.

In accordance with the present technique, a mapping of RNTI and short-identifiers (or "short-I Ds') is provided to the terminals in a sub-frame of the super-frame. In the example of Figure 6, the super-frame 104 consists of one frame in a time-dimension, and the correlation or correspondence 106 between a set of RNTIs and a set of short-lOs is communicated in the first sub-frame of the super-frame. Examples of such correspondence are given in Figures Ba to 8c, which are further discussed below. In this and the next sub-frames of the super-frame, the terminals can identify their down-link resource allocation using their short- ID. The terminals can also still use the longer RNTI, but it is advantageous to use the short-lOs, if possible, because it reduces the amount of resources to be used for allocation messages, e.g. PDCCI-is, as explained below.

In LTE, the RNTI is conventionally used to mask a cyclic redundancy check code (CRC) of the PDCCH transmission, where the RNTI and the PDCCH CRC are both 16 bits long. This is done by scrambling the PDCCH CRC with the RNTI. In accordance, if a PDCCI-l-like allocation message is to be sent, the short-ID which may for example be 8 bits could be used to mask a shorter CRC for example which may also be 8 bits or the short lDs of a plurality of terminals may be jointly coded within a PDCCH which allocates resources to a plurality of terminals where the 16 bit CRC is used for the PDCCH with a conventional format. Therefore, shorter allocation messages may be used and, because the number of short-ID to be used is lower than the number of possible RNTIs as provided by the LTE standard (210 possible RNTIs), the short-ID can be chosen to be much shorter than the RNTL, for example 4 bits. In this example situation, the allocation message can be reduced by 12 bits, thereby providing a reduction in size.

A further example is illustrated in Figure 10 with a three sub-frame super-frame 104.

The first sub-frame includes a table of correspondence 106 between three C-RNTI corresponding to three different terminals and short-IDs. In this example, this message is sent like any other downlink data, that is, in a Physical Down-link Shared Channel (PDSCH- 1) to which a PDCCH points. In another example, the correspondence information may be communicated in a different manner, for example within the PBCH. In Figure 10, the PDCCH allocating PDSCH-1 contains the Sl-RNTI such that all terminals within the cell decode the correspondence information 106. The same sub-frame also includes PDSCH-2 with data for the terminal with the C-RNTI "61465" (UE61465), where PDSCH-2 is allocated with a PDCCH or PDCCH-like message using the short ID "1", according to the information 106. In use, UE61465 would receive the first sub-frame; decode PDSCH-1 (like all terminals within the cell) such that it knows that short-ID "1" refers to its own C-RNTI; identify that PDSCI-I-2 is for UE61465 as well with the PDCCH for short-ID 1; and decode PDSCH-2. As is now apparent, the allocation messages, for example PDCCH and PDCCH-like messages, can be substantially reduced in size by using short-IDs within a super-frame. Therefore, more allocation messages can be included wahin the PDCCI-1 region and more PDSCH can therefore be allocated, if necessary.

As shown in Figure 10, in the next and second sub-frame, both newly-introduced short-lOs and legacy RNTIs may be used in the same sub-frame. In this example (JE61465 identifies that PDSCH-1 has to be decoded based on its C-RNTI "61465", and that PDSCH-2 has to be decoded based on its short-ID "1". Therefore, backward compatibility with traditional LTE is ensured, while shorter allocation messages using short-ID may be used.

The last sub-frame of the super-frame in Figure 10 shows an example where only short-IDs are used within a sub-frame. The super-frame could also be arranged to only include allocations based on short-IDs in every of its sub-frames.

For example and as shown schematically in Figure 7, the e-NodeB 2 is transmitting down-link data in two super-frames each of which includes correspondence information 106 transmitted in the example on the first sub-frame of each super-frame, where the data in each of the super-frame is only for terminals listed in the correspondence information 106.

As shown in Figure 7 a first group 110 is comprised of four communications devices and receives data in the first super-frame whereas a second group 112 is comprised of five terminals and receives data in the second super-frame. For ease of representation, the two groups have been represented as two completely distinct groups even though some terminals may be in both groups.

When and if forming groups, there are various ways of assigning terminals to groups which include: -By a type of device, for example smart meters are divided into a separate group whereas vending machines may be divided into a different group.

-By RNTI, for example the most significant "N" bits of the RNTI could define the group identity while the "16-n" least significant bits define the identity of terminals within the group.

-By an explicit assignment to a group, for example at call setup the base station could assign terminals to a particular group. This assignment could be fairly disparate, for example there could be a mix of RNTI's and device types within the group.

-By a pre-determined Group ID, for example provided within the terminal's profile in the HLR/HSS.

-By an expected amount and/or type of traffic from the terminal.

Generally, similar criteria may be used to decide which RNTI should be given a short ID within the correspondence information 106. Also, as the correspondence information matches a RNTI with a short-ID, it is possible to have correlated or uncorrelated to the matched RNTI and terminals. For example, one terminal may have two C-RNTIs but it may be decided that only one RNTI will be given a short-iD, if for example it is considered to be the only relevant RNTI to be given a short-ID. In another example, it may be decided that if one terminal-specific RNTI is given a short-ID, then all other terminal-specific RNTI identifying the same terminal are also given a short-ID, which can be the same as or different to the first shod-ID it has been given.

Also any suitable combination of RNTIs and short-ID may be provided, a few of which are illustrated in particular in Figure 8c. In this example, UE61465 and UE00237 have been given the same shod-ID "1" such that any data transmitted to the short-ID "1" will be decoded by both terminals. This can be useful if for example a new price list is to be sent to several vending machines. The vending machines in the same cell can be given the same shod-ID such that they will all receive the new price list with one message sent to this short-ID. Using the table of Figure 8c may not only help increase the number of PDCCH or PDCCH-Iike messages that can be sent in a sub-frames, it also increase the resources available for PDSCH data1 as the same data may be sent to a n terminals with only one PDSCH, rather than sending ii PDSCH (and n corresponding long or short PDCCH).

Any RNTI may be assigned a short-ID and thus, particular RNIls may also be assigned a short-ID. For example, in Figure Sc, RNTI 65535 has been given a short-ID, where this particular RNTI value corresponds in LIE to the Sl-RNII. If for example it is anticipated that the e-NodeB will be required to send several system information messages to all terminals in the cell in the next sub-frames, it can then be advantageous to have a short-ID corresponding to the Sl-RNTI in order to reduce the size of allocation messages for system information messages which are expected to be sent in the next sub-frames.

Figures 8a and Sb also show that the allocation may be an explicit allocation (Figure 8a) or an implicit allocation (Figure Sb) using for example the position of a RNTI in a list to infer the corresponding short-ID. Such an implicit allocation may for example helps reducing the size of the correspondence information 106 by simply sending the list of RNII that have been given a short-ID.

Figure 9 provides an illustrative representation of the operation of the terminals and the mobile radio network which implements communication using the super-frame structure and the short ID's explained above. In Figure 9 three terminals UE61465, UE10983 and UE00237 are shown to be communicating with an e-NodeB 2. Also shown is a serving gateway 6. The e-NodeB 2 receives from the serving gateway 6 a message to be communicated to the terminal UE61465. If a super-frame is being provided on the down-link or if it has been decided to provide one, the e-NodeB translate the RNTI 61465 into the short-ID "1" and insert a short allocation message with the short-ID within a downlink sub-frame of the super-frame, rather than insert a full-size PDCCH with the full-size C-RNTI.

The length of a super-frame may vary on super-frame by super-frame basis. For example a first super-frame may be 10 sub-frames long when the next one is B sub-frames long. Also the short-ID are intended to be allocated for the duration of a super-frame when a super-frame is of fixed duration. Even though the super-frame is initially intended to be used for short periods of time, possibly on a regular bases, the super-frame may also be provided for an undetermined length, on the assumption that the super-frame will be provided until it is not needed anymore. In such a case, the correspondence information may be updated one or more times whilst the super-frame is provided. Such updates provides flexibility to ensure the short-IDs utilization can be adjusted to better correspond to the current use of the down-link and the terminals can then maintain the correspondence between RNTIs and short-IDs up-to-date when receiving the updates.

A further example aspect includes an infrastructure equipment of a mobile communications system for communicating data to and/or from mobile terminals, the infrastructure equipment comprising a transmitter and a receiver which are arranged in operation to provide a wireless access interface for communicating the data to and/or from the mobile terminals, and a scheduler for allocating communications resources of the wireless access interface to the mobile terminals for communicating the data, wherein the wireless access interface provides a down-link frequency channel for communicating data to the mobile terminals, the down-link frequency channel being divided in time into different units of communications resource which are allocated by the scheduler of the infrastructure equipment to the mobile terminals, and a shared control channel for communicating resource allocation messages to the mobile terminals, each resource allocation message including an identification number allocated to one of the mobile terminals for indicating an allocation of one of the units of communications resource of the wireless access interface, and each of a plurality of the mobile terminals is divided into a plurality of different groups, and the infrastructure equipment is adapted to form super-frames comprising a plurality of the units of communications resource of the down-link channel, to transmit in a first of the super-frames control information providing for each of the plurality of mobile terminals in a first of the groups of devices a short identification number in association with the identification number allocated to the mobile terminal by the infrastructure equipment for use in allocating the units of communications resource to the mobile terminal for the first super-frame and to transmit in a second of the super-frames control information providing for each of the plurality of mobile terminals in a second of the groups of terminals a short identification number in association with the identification number allocated to the mobile terminal by the infrastructure equipment for use in allocating the units of communications resource to the mobile terminal for the second super-frame, and to adapt each of the resource allocation messages to include a plurality of the short identification numbers when allocating the units of communications resources to a plurality of the mobile terminals in the first or the second super-frames.

A further example method includes a method of operating an infrastructure equipment in a mobile communications network for communicating data to and/or from mobile terminals, the method comprising providing a wireless access interface from the infrastructure equipment for communicating the data to and/or from the mobile terminals, and allocating communications resources of the wireless access interface to the mobile terminals for communicating the data, wherein the providing the wireless access interface includes providing a down-link frequency channel for communicating data to the mobile terminals, the down-link frequency channel being divided in time into different units of communications resource which are allocated by the infrastructure equipment to the mobile terminals, and providing a shared control channel for communicating resource allocation messages to the mobile terminals, each resource allocation message including an identification number allocated to one of the mobile terminals for indicating an allocation of one of the units of communications resource of the wireless access interface, and the allocating the communications resources of the wireless access interface to the mobile terminals includes dividing each of a plurality of the mobile terminals into a plurality of different groups, forming a super-frame comprising a plurality of the units of communications resource of the down-link channel, transmitting in a first of the super-frames control information providing for each of the plurality of mobile terminals in a first of the groups of devices a short identification number in association with the identification number allocated to the mobile terminal by the infrastructure equipment for use in allocating the units of communications resource to the mobile terminal for the first super-frame, and transmitting in a second of the super-frames control information providing for each of the plurality of mobile terminals in a second of the groups of terminals a short identification number in association with the identification number allocated to the mobile terminal by the infrastructure equipment for use in allocating the units of communications resource to the mobile terminal for the second super-frame, and adapting each of the resource allocation messages to include a plurality of the short identification numbers when allocating the units of communications resources to a plurality of the mobile terminals in the first or the second super-frames.

Various further aspects and features of the present invention are defined in the appended claims. Various modifications may be made to the embodiments described above without departing from the scope of the present invention. For example, embodiment of the present invention finds application with other types of mobile communications networks providing downlink communications and is not limited to LTE or 3GPP networks. Annex

idintifrer ime To -usage P-RNTI Paging RNTI All UEs in the if a PDCCH (allocation message) with cell this RNTI is received, then all UEs read some PDSCH resource that has been allocated by the PDCCH. That PDSCH resource will then contain paging messages.

Sl-RNTI System All UEs in the If a PDCCH (allocation message) with Information cell this RNTI is received, then all UEs read RNTI some PDSCH resource that has been allocated by the PDCCH. That PDSCH resource will then contain system information for the cell.

RA-RWTI Random access One specific UE When a UE performs a RACH, it chooses RNTL a time-frequency resource (quasi-randomly) to use for the RACH. The time-frequency resource is mapped on a one-to-one basis with a RA-RNTI. The RA-RWTI is used to respond to the RACH.

C-RNT1 Cell RNTI One specific UE Used to schedule UEs with PDSCH resource during normal operation. The PDCCH that allocates a UE has its CRC bits scrambled with the C-RNT1. The C-RNTI is inherited from the T-RNTI.

The C-RNTI is re-allocated during the handover procedure.

Temporary-T-RNTI One specific UE Allocated during the random access RNTI response. The UE uses this T-RNTI until the contention resolution process is complete. Once contention resolution is complete, the T-RNTI becomes the C-RNTI.

SPS-RNTI Semi-persistent One specific UE schedungRNTl TPC-Transport power One specific UE PUSCH-control of

RNTI PUSCH RNJTI

TPC-Transmit power One specific UE PUCCH-control for

RNTI PUCCHRNTI

Claims (32)

1. cLAIMS 1. A mobile communications system for communicating data to and/or from mobile terminals1 the mobile communications system comprising a base station which includes a transmitter and a receiver which are arranged in operation to provide a wireless access interface for communicating the data to and/or from the mobile terminals and a scheduler for allocating communications resources of the wireless access interface to the mobile terminals for communicating the data, wherein the wireless access interface provides a down-link frequency channel for communicating data to the mobile terminals, the down-link frequency channel being divided in time into different units of communications resource which are allocated by the scheduler of the base station to the mobile terminals, and a shared control channel for communicating resource allocation messages to the mobile terminals, each resource allocation message including an identification number allocated to one of the mobile terminals for indicating an allocation of one of the units of communications resource of the wireless access interface, and each of a plurality of the mobile terminals is divided into a plurality of different groups, and the base station is adapted to form super-frames comprising a plurality of the units of communications resource of the down-link channel, to transmit in a first of the super-frames control information providing for each of the plurality of mobile terminals in a first of the groups of devices a short identification number in association with the identification number allocated to the mobile terminal by the base station for use in allocating the units of communications resource to the mobile terminal for the first super-frame, and to transmit in a second of the super-frames control information providing for each of the plurality of mobile terminals in a second of the groups of terminals a shod identification number in association with the identification number allocated to the mobile terminal by the base station for use in allocating the units of communications resource to the mobile terminal for the second super-frame, and to adapt each of the resource allocation messages to include a plurality of the short idenfification numbers when allocating the units of communications resources to a plurality of the mobile terminals in the first or the second super-frames.
2. 2. A mobile communications system as claimed in Claim 1, wherein one of the short identification numbers in the first super-frame is allocated to identify a different mobile terminal from the second group of devices in the second frame.
3. 3. A mobile communications system as claimed in Claim I or 2, wherein the control information comprises an indication of the units comprised in the super-frame.
4. 4. A mobile communications system of claim 3, wherein the indication provides a number of subsequent units in the super-frame and indicates the first unit of the super-frame.
5. 5. A mobile communications system of claim 3, wherein the indication comprises a list of units comprised in the super-frame.
6. 6. A mobile communications system of claim 1, wherein the base station is operable to transmit a resource allocation message to one of the mobile terminals of the second group which is not a member of the first of the groups of mobile terminals in the first super frame, the resource allocation message including the identification number of the mobile terminal.
7. 7. A mobile communications system as claimed in any preceding Claim, the mobile communications system is arrange to select the identification numbers based on at Least a profile of the one or more terminals corresponding to the identifier.
8. 8. A mobile communications system as claimed in Claim 7, wherein the selecting the identification numbers includes selecting the identification numbers for the mobile terminals based on at least an expected traffic amount and/or type from the one or more terminals corresponding to the identifier.
9. 9. A mobile communications system of any preceding Claim, wherein the identification number is a Radio Network Temporary Identifier.
10. 10. A method of communicating data to and/or from mobile terminals in a mobile communications system, the method comprising providing a wireless access interface from a base station of the mobile communications system for communicating the data to and/or from the mobile terminals, and allocating communications resources of the wireless access interface to the mobile terminals for communicating the data, wherein the providing the wireless access interface includes providing a down-link frequency channel for communicating data to the mobile terminals, the down-link frequency channel being divided in time into different units of communications resource which are allocated by the base station to the mobile terminals, and providing a shared control channel for communicating resource allocation messages to the mobile terminals, each resource allocation message including an identification number allocated to one of the mobile terminals for indicating an allocation of one of the units of communications resource of the wireless access interface, and the allocating the communications resources of the wireless access interface to the mobile terminals includes dividing each of a plurality of the mobile terminals into a plurality of different groups, forming a super-frame comprising a plurality of the units of communications resource of the down-link channel, transmitting in a first of the super-frames control information providing for each of the plurality of mobile terminals in a first of the groups of devices a short identification number in association with the identification number allocated to the mobile terminal by the base station for use in allocating the units of communications resource to the mobile terminal for the first super-frame, and transmitting in a second of the super-frames control information providing for each of the plurality of mobile terminals in a second of the groups of terminals a short identification number in association with the identification number allocated to the mobile terminal by the base station for use in allocating the units of communications resource to the mobile terminal for the second super-frame, and adapting each of the resource allocation messages to include a plurality of the short identification numbers when allocating the units of communications resources to a plurality of the mobile terminals in the first or the second super-frames.
11. 11. A method as claimed in Claim 10, wherein one of the short identification numbers in the first super-frame is allocated to identify a different mobile terminal from the second group of devices in the second frame.
12. 12. A method as claimed in Claim 10 or 11, wherein the control information comprises an indication of the units comprised in the super-frame.
13. 13. A method of claim 12, wherein the indication provides a number of subsequent units in the super-frame and indicates the first unit of the super-frame.
14. 14. A method of claim 12, wherein the indication comprises a list of units comprised in the super-frame.
15. 15. A method of claim 10, the method comprising transmitting a resource allocation message to one of the mobile terminals of the second group which is not a member of the first of the groups of mobile terminals in the first super frame, the resource allocation message including the identification number the mobile terminal.
16. 16. A method of any of claims 10 to 16, the method comprising selecting the identification numbers based on at least a profile of the one or more terminals corresponding to the identifier number.
17. 17. A method of as claimed in Claim 16, wherein the selecting the identification numbers includes selecting the identification numbers for the mobile terminals based on at least an expected traffic amount and/or type from the one or more terminals corresponding to the identifier.
18. 18. A method of any of Claims 8 to 13, wherein the identification number is a Radio Network Temporary Identifier.
19. 19. A terminal for use in a mobile communications network, the terminal including a receiver operable to receive data on a down-link frequency channel, the down-link frequency channel being divided in time into different sub-frames, wherein the terminal is operable: to, upon reception of an allocation message from a base station, detect an identifier in the allocation message, an identifier being for identifying the allocation of communications resources on the downlink channel to one or more terminals; wherein the base station is adapted: to receive control information in a sub-frame of a super-frame, the control information providing each identifier in a list of identifiers with a corresponding short identification number for use in the super-frame, and to, upon reception of an adapted allocation message, detect the short identification number and identify the identifier corresponding the short identification number.
20. 20. A terminal of claim 19, wherein the control information providing correspondences between a set of identifiers and a set of short identification numbers is updated on a per super-frame basis.
21. 21. A terminal of claim 19 or 20, wherein the control information comprises an indication of the sub-frames comprised in the super-frame.
22. 22. A terminal of claim 21, wherein the indication provides a number of subsequent sub-frames in the super-frame and indicates the first sub-frame of the super-frame.
23. 23. A terminal of claim 21, wherein the indication comprises a list of sub-frames comprised in the super-frame.
24. 24. A terminal of any claims 19 to 23, wherein the identifier is a Radio Nietwork Temporary ldentifier.
25. 25. A method for use in a terminal, the terminal including a receiver operable to receive data on a down-link frequency channel, the down-link frequency channel being divided in time into different sub-frames, wherein the method comprises: upon reception of an allocation message from a base station, detecting an identifier in the allocation message, an identifier being for identifying the allocation of communications resources on the downlink channel to one or more terminals; wherein the base station is adapted: receiving control information in a sub-frame of a super-frame, the control information providing each identifier in a list of identifiers with a corresponding short identification number for use in the super-frame, and upon reception of an adapted allocation message, detecting the short identification number and identifying the identifier corresponding the short identification number.
26. 26. A method of claim 25, wherein the control information providing correspondences between a set of identifiers and a set of short identification numbers is updated on a per super-frame basis.
27. 27. A method of claim 25 or 26, wherein the control information comprises an indication of the sub-frames comprised in the super-frame.
28. 28. A method of claim 27, wherein the indication provides a number of subsequent sub-frames in the super-frame and indicates the first sub-frame of the super-frame.
29. 29. A method of claim 27, wherein the indication comprises a list of sub-frames comprised in the super-frame.
30. 30. A method of any of claims 25 to 29, wherein the identifier is a Radio Network Temporary Identifier.
31. 31. A mobile communications system or a mobile terminal substantially as herein before described with reference to the accompanying drawings.* 10
32. 32. A method for communicating data to mobile terminals or a method for use in a mobile terminal substantially as herein before described with reference to the accompanying drawings.