WO2013016862A1

WO2013016862A1 - Small downlink data transmissions

Info

Publication number: WO2013016862A1
Application number: PCT/CN2011/077849
Authority: WO
Inventors: Haiming Wang; Jing HAN; Jianke Fan; Wei Bai
Original assignee: Renesas Mobile Corporation
Priority date: 2011-08-01
Filing date: 2011-08-01
Publication date: 2013-02-07

Abstract

A network determines that there is data (e.g., a small data packet) to be sent to a radio device (e.g., M2M device) which is not in a connected state, and compiles a paging message directed to the device which includes the data. This avoids the signaling overhead of changing the device to a connected state to receive the small data packet. The radio device receives the paging message with the piggybacked downlink data at a lower protocol layer (e.g., RRC layer) where the data is separated from the paging message, and the separated data is then forwarded to a higher protocol layer (e..g, NAS layer) for processing (e.g., decoding). Various embodiments are presented as to how to insert the small data into the paging message, sending the data to one or multiple radio devices, and retaining the radio device context and security while it is not in a connected state.

Description

SMALL DOWNLINK DATA TRANSMISSIONS

TECHNICAL FIELD:

[0001] The exemplary and non-limiting embodiments of this invention relate generally to wireless communication systems, methods, devices and computer programs, and more specifically relate to small data transmissions such as might be sent to M2M devices by a cellular network.

BACKGROUND:

[0002] The following abbreviations that may be found in the specification and/or the drawing figures are defined as follows:

3GPP third generation partnership project

CCCH common control channel

C-RNTI cell RNTI

DL downlink

eNB evolved Node B (base station of a LTE/LTE-A network)

E-UTRAN evolved universal terrestrial radio access network (LTE)

LTE long term evolution

LTE- A long term evolution- advanced

M2M machine-to-machine

MAC medium access control

MME mobile management entity

MTC machine type communications

RAN radio access network

RNTI radio network temporary identifier

RRC radio resource control

UE user equipment

UL uplink

[0003] M2M communications is the networking of intelligent, communications-enabled remote assets which allows the exchange of information automatically without human intervention M2M covers a broad range of technologies and applications which connect the physical world - whether machines or monitored physical conditions - to a back-end information technology IT infrastructure. M2M communications can be used for a variety of purposes such as immediate feedback on a remote asset, feature popularity, and specifics of errors and breakdowns to name a few. The ultimate future target is IoT (Internet of Things).

[0004] M2M communications are made possible by the use of intelligent sensors or microprocessors that are embedded in the remote asset. These sensors are connected to a wireless modem, typically slightly different to the one in conventional mobile phones, which is able to receive and transmit data wirelessly to a central server where it can be analyzed and acted upon. Wireless communications technologies used to enable this connectivity include GSM, GPRS, CDMA, 3G, LTE/LTE-A, WiFi and WiMAX. M2M communications can be over a relatively short range or a distance of many miles. Since there is a wide variety for M2M communications in both the types of data reported and the radio access technologies used, the traffic models are quite diverse and no single networking model is efficient for them all. The US patent application referenced above concerns M2M UL communications. These teachings relate to downlink communications to an M2M device but are not limited only to M2M devices.

[0005] In 3GPP, MTC has been studied in the 3GPP RAN group since January 2010.

Currently there is an ongoing study item for MTC concerning RAN improvements, focusing on avoiding RAN overload to protect normal legacy UEs and to improve RAN efficiency when a very large number of MTC devices are accessed at once. [0006] 3 GPP TS 22.368 v 10.5.0 (2011-06), entitled Service requirements for Machine-Type Communications (MTC), defines small data transmission as a feature of MTC. Document R2-111812 by 3 GPP TSG SA and entitled Reply LS on MTC Planning and Prioritization (3 GPP TSG RAN WG2 meeting #73bis; Shanghai, China; 1 1-15 April 201 1) requests that small data transmission become a prioritized feature/requirement for development of MTC procedures. Research directed toward MTC small data transmissions consider the expectation that there will be potentially a very large number of MTC devices, each of which sends or receives only a relatively small amount of data on each separate and distinct communication with other MTC devices or the central server. Thus the conventional RANs designed for human users who exchange relatively large data volumes per session need to support high numbers of M2M devices each sending small volumes of data, while still supporting the traditional human-oriented UEs such as mobile phone handsets.

[0007] One proposed technique for DL small data transmission is set forth in document R2-1 12940 by Renesas Mobile Europe and entitled RAN Efficiency Improvement Schemes (3 GPP TSG RAN WG2 meeting #74; Barcelona, Spain; 9-13 May 201 1). There it is proposed to use multimedia broadcast multicast MBMS service to carry DL packets for MTC devices. The drawback is that MBMS is a multicast service targeted for multiple UEs, meaning the network eNB could not communicate with single UE or M2M device. Additionally, MBMS will need a multi-media broadcast over a single frequency network MBSFN subframe configuration in every radio frame, meaning the total subframe could not be used by the cellular UE which creates potentially a relatively large overhead cost on the cellular network.

[0008] These teachings are directed toward adapting conventional cellular network protocols, which were originally developed for human-oriented communications, to more efficiently support downlink MTC communications of small amounts of data.

SUMMARY:

[0009] The foregoing and other problems are overcome, and other advantages are realized, by the use of the exemplary embodiments of this invention.

[0010] In a first exemplary embodiment of the invention there is an apparatus comprising a processing system. The processing system comprises a memory storing a set of computer instructions and at least one processor, and is arranged to at least: determine that there is data to be sent to a radio device which is not in a connected state; and compile a paging message, directed to the radio device, which includes the data.

[001 1 ] In a second exemplary embodiment of the invention there is a method comprising: determining that there is data to be sent to a radio device which is not in a connected state; and compiling a paging message, directed to the radio device, which includes the data,

[00 2] In a third exemplary embodiment of the invention there is a computer readable memory tangibly storing a computer program which is executable by at least one processor. In this embodiment the computer program comprises: code for determining that there is data to be sent to a radio device which is not in a connected state; and code for compiling a paging message, directed to the radio device, which includes the data.

[0013] In a fourth exemplary embodiment of the invention there is an apparatus comprising a processing system. The processing system comprises a memory storing a set of computer instructions and at least one processor, and in this embodiment the processing system is arranged to at least: receive at a lower protocol layer of the apparatus a paging message with piggybacked downlink data, and separate the data from the paging message; and forward the separated data from the lower protocol layer to a higher protocol layer of the apparatus for processing.

[0014] In a fifth exemplary embodiment of the invention there is a method comprising: receiving at a lower protocol layer of an apparatus a paging message with piggybacked downlink data, and separating the data from the paging message; and forwarding the separated data from the lower protocol layer to a higher protocol layer of the apparatus for processing. [0015] In a sixth exemplary embodiment of the invention there is a computer readable memory tangibly storing a computer program which is executable by at least one processor. In this sixth embodiment the computer program comprises: code for separating, at a lower protocol layer of an apparatus at which is received a paging message with piggybacked downlink data, the data from the paging message; and code for forwarding the separated data from the lower protocol layer to a higher protocol layer of the apparatus for processing.

[0016] These and other embodiments and aspects are detailed below with particularity.

BRIEF DESCRIPTION OF THE DRAWINGS:

[0017] Figure 1 illustrates an LTE paging message for a single radio device and having a piggybacked small data packet included in a PagingRecord portion of the paging message according to an exemplary embodiment of these teachings.

[0018] Figure 2 illustrates an LTE paging message for multiple radio devices and having a piggybacked small data packet included as a new information element (IE) within the paging message according to an exemplary embodiment of these teachings.

[0019] Figure 3 illustrates an LTE paging message which uses the RNTI for the radio device, which the network retains despite the radio device not being in a connected state according to an exemplary embodiment of these teachings. [0020] Figures 4-5 are logic flow diagrams that each illustrates from the respective perspective of the network and of the radio device the operation of a method, and a result of execution of a set of computer program instructions embodied on a computer readable memory, in accordance with exemplary embodiments of this invention. [0021] Figure 6 is a simplified block diagram of a radio device and two different network nodes which are exemplary electronic devices suitable for use in practicing the exemplary embodiments of this invention.

DETAILED DESCRIPTION:

[0022] Before detailing specific exemplary embodiments of these teachings, first consider the conventional manner in which data is sent to a conventional (non M2M device) UE in the LTE system. In current LTE specifications there have two RRC states for a UE; RRCJDLE and RRC CO ECTED. When there is to be a data transmission either DL to or UL from a UE, the UE must be in the RRC_CONNECTED state. If the UE is in the RRCJDLE state it needs to transition to the RRC_CONNECTED state first before any data transmission can occur.

[0023] Assuming a subject UE begins in the RRCJDLE state and after the data transmission goes back to the RRCJDLE state to save power, in conventional LTE procedures set forth at 3 GPP TS 36.331 vlO.2.0 (201 1-06) Radio Resource Control (RRC) the following messages and procedures are needed.

a) RRC connection establishment procedure: totally three RRC messages are needed: RRCConnectionRequest message, RRCConnectionSetup message, RRCConnectionSetupComplete message;

b) Initial security activation procedure: totally two RRC messages are needed:

SecurityModeCommand message and SecurityModeComplete message;

c) RRC connection reconfiguration procedure: totally two RRC messages are needed: RRCConnectionReconfiguration message,

RRCConnectionReconfigurationComplete message; d) RRC connection release procedure: one RRC message: RRCConnectionRelease message;

This is a total of eight RRC messages and four RRC procedures in order to complete a data transmission to or from a UE which is not already in the RRC_CONNECTED state.

[0024] Consider also that the MTC communications are to be for small data volumes. In the 3GPP system if there is a small volume of data involved it can be sent at a low data rate, which may is on the order of 10 kbps (see for example document RP-1 10419 by Vodaphone and Sagemcom SAS entitled MTC device migration from GSM at 3 GPP TSG-RAN#51 ; Kansas City, USA; 15-18 March 201 1). This is relatively low for a UE operating in the LTE system; such a UE could reach 10 kbits in 1 ms which is a single transmission time interval (see for example 3GPP TS 36.306 vl0.2.0 (2011-06), User Equipment (UE) radio access capabilities).

[0025] The definition of small data transmission in the MTC regime is not universally fixed. By the terms of 3GPP TS 22.368 referenced in the background section above, the definition of a small data shall be configurable per subscription or by network operator policy. While a low data rate MTC device is not equivalent to small data transmission MTC devices, and regardless of the exact definition of small data transmission, it is expected that the size of the packet of small data transmission to or from MTC devices is relative small, reasonably about one hundred bits or less. Moreover, the periodicity of MTC packet transmission to or from any given M2M device is rather long, for example tens of seconds or even hours. For such long latent periods each new small data transmission for a given MTC device would, if conventional UE procedures were used, result in the entire RRC procedures summarized above for each packet transmission. It is clear then that conventional RRC messages and procedures impose a very large signaling overhead to transmit one or several small packets.

[0026] Exemplary embodiments of these teachings avoid the state transitions between RRC JDLE and R C_CO ECTED which conventional UEs undergo in an LTE cell. While the specific examples below are in the context of the RAN being a LTE or LTE-A system, this is simply one of many RANs in which these teachings may be utilized to advantage. While different RANS use different names for the UE mobility states, IDLE and CONNECTED are fairly universal among modern wireless cellular networks even if those exact names are not used. [0027] According to the exemplary embodiments set forth in detail below the cellular system is enabled to send small amounts of data to MTC Devices with minimal network impact on signaling overhead, network resources and delay. In broad terms, the conventional paging procedure is extended by these teachings to contain DL data packets for MTC devices which are not in a connected state with the cellular network. This decreases the signaling overhead needed to get a DL packet of data to the MTC device because there are no RRC state transitions, and so all of the signaling overhead and delay associated with those are avoided. Like IDLE and CONNECTED states, different RANs have different procedures for paging. The exemplary embodiments below are specific to LTE and LTE-A but these teachings are not limited only to those RANs. Also, the examples below are in the context of a network access node/eNB sending the small data transmission DL to the MTC device.

[0028] Further, the recipient of the DL small data transmission need not be an MTC device but may be any radio device for which the network has only a small amount of data to send. The device to which the small data transmission is addressed need not receive it directly from the network access node either; in some deployments remote MTC devices may be in contact with a cellular network only through other MTC devices which relay between the remote device and a network access node. In this case the data is still DL even though the last hop or hops to the addressee is lateral between MTC devices rather than direct DL from a radio access network. To clarify these additional embodiments the examples below characterize the device to which the small data transmission is addressed as a radio device, which may or may not be mobile and may or may not be operating from a limited power supply (some MTC devices serving a sensor function such as traffic or fuel tank monitors may be fixedly mounted and connected to an AC power supply with battery serving only as a backup).

[0029] In an exemplary embodiment the radio device is in a RC_IDLE state and the RAN access node inserts the small data transmission into a paging message addressed to the radio device. In this manner the small data packet is 'piggybacked' onto the paging message. If the small data is directed to only one radio device the network can dedicate the paging message to only that single radio device. In order to further save on signaling overhead the network can piggyback the small data packet onto a paging message directed to multiple radio devices if it is intended for more than only one. [0030] Figure 1 illustrates a paging message 100 adapted according to these teachings and directed to a single radio device. In the Figure 1 embodiment the piggybacked data 102 for a specific (single) radio device is included in the PagingRecord portion 104 of the paging message 100. In this exemplary embodiment the RAN network can send the piggybacked small data packet to one radio device, or by extension to send different small data packets disposed in different paging messages 100 each addressed to a different radio device, In this case there is a Boolean indication inserted in a new 'data indication' field 106 which tells the recipient whether or not there is a small data packet within the paging message 100, and the actual bits of the small data are included in another new field 'piggybacked data' 108.

[0031] Figure 2 illustrates a paging message 200 adapted according to these teachings and directed to multiple radio devices. In the Figure 2 embodiment the piggybacked data 202 for multiple radio devices is included as a separate 'piggybacked data information element' (IE) in the paging message 200. In this exemplary embodiment the RAN network can send the same small data packet to multiple recipients simultaneously by piggybacking it into a paging message 200 addressed to multiple radio devices in the paging record list 204. In this case there is an indication 206 that a piggybacked data IE is present in the 'noncritical extension' field of the paging message 200. For the case in which there is a common small data packet destined for multiple radio devices at once this saves on signaling overhead as compared to a different paging message according to Figure 1 sent to each destination radio device. [0032] For the case in which the network has different small data packets for different radio devices at the same time, signaling overhead can be saved by using a variation of the Figure 1 embodiment. In this case the network would insert the different small data packets for the different radio devices into the paging record 104 of a single paging message 100, and Figure 1 would be modified so that there are multiple piggybacked data IES in place of the bits for the piggybacked data 108 now shown at Figure 1,

[0033] In this manner the network can send the small data transmission to the radio device even while the radio device remains in a RRCJGDLE state.

[0034] Conventionally in LTE a UE is assigned a new C-RNTI when it enters the RRC_CONNECTED state, and the network takes back that assigned C-RNTI for use with other UEs when the first UE goes to the RRC_IDLE state or leaves the cell. In exemplary embodiments of these teachings the network keeps the C-RNTI reserved for a given radio device even while it is in the RRC_IDLE state. This is because retaining the C-RNTI is a simple way to enable security on the data packet sent downlink within the paging message; by including the previously-assigned C-RNTI in the paging message which carries the small data packet. The network may do this simultaneously for some radio devices but not for others (e.g., those whose discontinuous reception paging period is on the order of seconds versus those whose similar period is on the order of hours) so as not to deplete its reservoir of C-RNTI values for use in the cell. [0035] Reserving the C-RNTI value which is first assigned to a radio device during its initial access in the cell for that same radio device even after it enters the RRC_IDLE mode implies that the eNB (or a node in the core network) also saves the radio device's security information which the network obtains during that initial access process. Conventionally the network dynamically updates the UE's security information when the UE changes its mobility state, such as when it roams in different networks.

[0036] In accordance with these exemplary embodiments the radio device whose C-RNTI is saved in the network despite not having a logical channel allocated to it will be in what might be considered a RRC semi-connected state or a RRC semi-idle state, and the network will save that radio device's C-RNTI and its related security keys in a higher layer (e.g., above the physical and MAC layers). Having the radio device's assigned C-RNTI enables the eNB to send paging information, or to perform grouping of the radio device with other radio devices/UEs for various purposes in the cell.

[0037] In this embodiment the paging can be done by the eNB, or by the core network with the paging message merely passed through the eNB for transmission. If the paging message is compiled at the core network, the radio device identity for the paging information would be provided by the core network without being exposed to the eNB which does not open the paging message it receives from the core network. If the paging message is compiled at the eNB then the radio device identity for the paging information would be informed or saved at the eNB itself. In conventional LTE it is the core network which compiles the paging messages. [003B] Figure 3 illustrates an exemplary paging message 300 in which the paging record field 304 enumerates the radio device paging identity which is conventional for a UE in LTE (used to fetch the UE context), and additionally according to these teachings it also lists the radio device's C-RNTI. In this paging message 300 there is a newly added PagingUE-CRNTI field 310 which also gives the radio device's C-RNTI, a physical cell identifier, and a short MAC identifier. These are detailed in the table below:

PagingUE-CRNTI field descriptions

ue-Identity: the UE identity is included to retrieve UE/radio device context and to facilitate contention resolution by lower layers.

shortMAC-I: this indicates and verifies the UE/radio device using the security configuration of the source cell.

physCellld: this is the Physical Cell Identity of the cell the UE/radio device was connected to prior to the failure, or to which the UE/radio device is 'attached' to in the idle or semi-idle state if there was no failure. The piggybacked data for the Figure 3 embodiment can be disposed within the paging record 104 as shown for Figure 1, or as separate piggybacked data IEs 202 which are outside the paging record portion 204 as shown at Figure 2.

[0039] Regardless of which of the above embodiments or others are used to insert the small data packet into the paging message, the radio device will receive the DL paging message as is conventional in its RRC protocol layer. In an embodiment the RRC layer of the radio device will see that there is data included, separate that data from the paging message itself and forward the separated data to a higher protocol layer within the radio device for decoding and processing. In an embodiment this higher layer is the network access stratum NAS layer. More generally, the paging message with the included data is received at a lower protocol layer, and after being separated from the paging message the data is forwarded to an upper protocol layer.

[0040] The above exemplary embodiments provide several technical effects and advantages. Specifically, they enable the network/eNB to send small data transmissions to the radio device when the radio device is in the RRCJDLE mode (or a newly defined semi-idle mode as noted above), which avoids large RRC signaling overhead associated with RRC state transitions. Certain embodiments also enable the network/eNB to send small data transmissions to individual radio devices, or to send different small data transmissions to different radio devices at the same time; or to send the same data to multiple UEs at the same time so as to avoid duplicate paging messages. The advantages are most pronounced where the radio device is either fixed or has only low mobility to assure the paging message could be restricted to a specific tracking area or eNB cell. Since the paging load is increased (minimally in the above examples, expected to be tens or up to about a hundred bits only) there may be some adverse effect on system performance overall for the cellular network, but the alternative of RRC state transitions is seen to have a greater adverse effect where the data being sent is small relative to signaling overhead needed for mobility state transitions.

[0041] Figures 4-5 detailed below are logic flow diagrams illustrating exemplary but non-limiting embodiments of the invention from the perspective of the network and of the recipient radio device, respectively. The functional blocks shown at Figures 4-5 may represent method steps, actions taken by a network node or the radio device in response to stored software arranged according to these embodiments, or the actual network node or radio device themselves which are configured according to these teachings.

[0042] Consider first Figure 4 which describes from the perspective of the cellular network which eventually transmits the paging message. This may be the perspective of the network access node/eNB, or the perspective of another higher node such as may be in the core network as detailed above for various embodiments. According to these exemplary embodiments of the teachings herein, at block 402 the network node (or one or more components thereof) determines that there is data to be sent to a radio device in which the radio device is not in a connected state (though it may be in a semi-connected/semi-idle state as in certain examples above). Then at block 404 the network node compiles a paging message, directed to the radio device, which includes the data. For the case Figure 4 reads on the access node, that access node would then transmit the paging message it compiled. Otherwise for the case of a core network node that node would forward the compiled paging message to an access node for transmission to the radio device.

[0043] Further details at Figure 4 summarize various of the non-limiting embodiments detailed above with particularity. Specifically, block 406 details that the data and the paging message are directed to only the radio device (not multiple radio devices), and the data is piggybacked in a paging record portion of the compiled paging message. Another embodiment is shown at block 408 in which the data is to be sent to a plurality of radio devices, and the data in the compiled message is piggybacked in at least one information element of the paging message.

[0044] The embodiments of block 410 and 412 can be combined with any of blocks 406 or 408 (and block 412 can be combined also with block 410), and tells that the paging message is addressed to a RNTI which was first assigned to the radio device by the network upon an initial access of the radio device to a radio access network of which the network access node is a part. Block 412 specifies that the data is a machine type communication which the network access node receives for forwarding to the radio device, and also specifies that the radio device is a M2M communication device.

[0045] Now consider Figure 5 which describes from the perspective of the radio device which receives the paging message. According to these exemplary embodiments of the teachings herein, at block 502 the radio device (or one or more components thereof) receives at a lower protocol layer a paging message with piggybacked downlink data and the piggybacked downlink data is separated from the paging message. Then at block 504 that separated data is forwarded from the lower protocol layer to a higher protocol layer for (further) processing, such as for example decoding.

[0046] Further details at Figure 5 summarize various of the non-limiting embodiments detailed above with particularity. Specifically, block 506 details that the lower protocol layer is a RRC layer and the higher protocol layer is a network access stratum NAS layer. Block 508 tells the embodiment in which the piggybacked downlink data is in one of a paging record portion or an information element of the paging message received at the lower protocol layer. And block 510 summarizes the embodiment in which the paging message received at the lower protocol layer is addressed to a RNTI which was first assigned to the radio device by a network access node of a RAN upon an initial access of the radio device to that RAN.

[0047] While not explicitly stated at Figure 5, it is noted again that the exemplary embodiments above in which the paging message with the piggybacked downlink data is a MTC for which the radio device is a M2M device are non-limiting to the broader teachings presented herein. In that same regard, the blocks of Figures 4-5 and the functions they represent are non-limiting examples, and may be practiced in various components such as integrated circuit chips and modules, and the exemplary embodiments of this invention may be realized in an apparatus that is embodied as an integrated circuit. The integrated circuit, or circuits, may comprise circuitry (as well as possibly firmware) for embodying at least one or more of a data processor or data processors, a digital signal processor or processors, baseband circuitry and radio frequency circuitry that are configurable so as to operate in accordance with the exemplary embodiments of this invention.

[0048] Reference is now made to Figure 6 for illustrating a simplified block diagram of various electronic devices and apparatus that are suitable for use in practicing the exemplary embodiments of this invention. In Figure 6 a wireless radio access network is adapted for communication over a wireless link 21 with an apparatus, such as a mobile terminalAJE or other such MTC device 20 (termed above more generally as a radio device), via a network access node, such as a base or relay station or more specifically an eNB 22. The radio access network may include a network control element embodied as a mobility management entity/serving gateway MME/SGW 23, which provides connectivity with further networks (e.g., a publicly switched telephone network PSTN and/or a data communications network/Internet) as well as other network elements. Shown at Figure 6 also is a core network CN server 24 which is connected to the eNB 22 via the MME/S-GS 23. The MTC device 20 may be any host device of a MTC-specific SIM card, or an ordinary SIM card, or even a radio device lacking a SIM card.

[0049] The MTC radio device 20 includes processing means such as at least one data processor (DP) 20A, storing means such as at least one computer-readable memory (MEM) 20B storing at least one computer program (PROG) 20C executable by the MTC device 20 which cause the device 20 to perform actions as detailed above, communicating means such as a transmitter TX 20D and a receiver RX 20E for bidirectional wireless communications with the eNB 22 via one or more antennas 20F. Also shown in the MEM 20B at reference number 20G are two layers of its protocol stack, of which the lower RRC layer is configured according to these teachings to receive the paging message and separate the small data packet from that message, and the higher NAS layer which processes/decodes the data after the separated data is forwarded to this higher layer by the lower RRC layer. A SIM card is not specifically shown but if present for implementing certain embodiments of these teachings in a MTC radio device 20 includes a processor and a memory storing a computer program which when executed by one or more processors causes the protocol stack to operate as above. [0050] The eNB 22 also includes processing means such as at least one data processor (DP) 22A, storing means such as at least one computer-readable memory (MEM) 22B storing at least one computer program (PROG) 22C executable by the eNB 22 which cause the device 22 to perform actions as detailed above, and communicating means such as a transmitter TX 22D and a receiver RX 22E for bidirectional wireless communications with the UE 20 via one or more antennas 22F. There is a data and/or control path 25 coupling the eNB 22 with the MME/SGW 23, and another data and/or control path 23 coupling the eNB 22 to other eNBs/access nodes. The eNB 22 has at block 22G a functional compiler which is configured according to these teachings to insert small data packets into paging messages. Such a compiler 22G may be implemented in hardware, tangibly stored software, or a combination of them both. [0051] Similarly, for embodiments in which a node in the CN does the compiling, the CN server 24 includes processing means such as at least one data processor (DP) 24A, storing means such as at least one computer-readable memory (MEM) 24B storing at least one computer program (PROG) 24C of executable instructions, and communicating means such as a modem 24H for bidirectional communications with the eNB 22 via the MEME/S-GW 23 and its data/control path 25. While not particularly illustrated for the UE 20 or eNB 22, those devices are also assumed to include as part of their wireless communicating means a modem which may be inbuilt on an RF front end chip within those devices 20, 22 and which also carries the TX 20D/22D and the RX 20E/22E. Such a modem implementing embodiments of these teachings may include the functionality described for blocks 20G and 22G. For the CN server 24, it also is shown to include a compiler 24G which functions similar to that shown for the eNB 22.

[0052] At least one of the PROGs 20C in the MTC radio device 20 is assumed to include a set of program instructions that, when executed by the associated DP 20A, enable the device to operate in accordance with the exemplary embodiments of this invention, as detailed above. The eNB 22 and CN server 24 may also have software to implement certain aspects of these teachings for compiling paging messages as detailed above, In these regards the exemplary embodiments of this invention may be implemented at least in part by computer software stored on the MEM 20B, 22B which is executable by the DP 20A of the MTC radio device 20 and/or by the DP 22A of the eNB 22 and/or by the DP 24A of the CN server 24, or by hardware, or by a combination of tangibly stored software and hardware (and tangibly stored firmware). Electronic devices implementing these aspects of the invention need not be the entire MTC radio device 20 or eNB 22 or CN server 24, but exemplary embodiments may be implemented by one or more components of same such as the above described tangibly stored software, hardware, firmware and DP, an application specific integrated circuit ASIC or a system on a chip SOC, which for the MTC radio device may be a MTC-specific SIM card.

[0053] In general, the various embodiments of the MTC device 20 can include, but are not limited to personal portable digital devices having wireless communication capabilities, including but not limited to cellular telephones, navigation devices, laptop/palmtop/tablet computers, digital cameras, music devices, and Internet appliances, [0054] Various embodiments of the computer readable MEMs 20B, 22B and 24B include any data storage technology type which is suitable to the local technical environment, including but not limited to semiconductor based memory devices, magnetic memory devices and systems, optical memory devices and systems, fixed memory, removable memory, disc memory, flash memory, DRAM, SRAM, EEPROM and the like. Various embodiments of the DPs 20A, 22A and 24A include but are not limited to general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and multi-core processors.

[0055] Various modifications and adaptations to the foregoing exemplary embodiments of this invention may become apparent to those skilled in the relevant arts in view of the foregoing description. While the exemplary embodiments have been described above in the context of the E-UTRAN/LTE and LTE-A systems, it should be appreciated that the exemplary embodiments of this invention are not limited for use with only this one particular type of wireless communication system, and that they may be used to advantage in other wireless communication systems such as for example UTRAN, GERAN and GSM and others which may use paging messages (or similar, even if not explicitly termed paging messages) for signaling a radio device which is currently in other than a connected state with the radio access network,

[0056] Further, some of the various features of the above non-limiting embodiments may be used to advantage without the corresponding use of other described features. The foregoing description should therefore be considered as merely illustrative of the principles, teachings and exemplary embodiments of this invention, and not in limitation thereof.

Claims

CLAIMS:

1. An apparatus comprising:

a processing system comprising a memory storing a set of computer instructions and at least one processor, in which the processing system is arranged to at least:

determine that there is data to be sent to a radio device which is not in a connected state; and

compile a paging message directed to the radio device, which includes the data.

2. The apparatus according to claim 1, in which the data and the paging message are directed to only the radio device, and the data is piggybacked in a paging record portion of the compiled paging message.

3. The apparatus according to claim 1 , in which the data is to be sent to a plurality of radio devices, and the data in the compiled message is piggybacked in at least one information element of the paging message.

4. The apparatus according to any one of claims 1 through 3, in which the apparatus comprises an access node of a radio access network or a node of a core network, and the paging message is addressed to a radio network temporary identifier which was first assigned to the radio device by the apparatus upon an initial access of the radio device to the radio access network.

5. The apparatus according to claim 4, in which the data is a machine type communication which the apparatus receives for forwarding to the radio device which is a machine-to-machine communication device.

6. A method, comprising:

determining that there is data to be sent to a radio device which is not in a connected state; and

compiling a paging message, directed to the radio device, which includes the data.

7. The method according to claim 6, in which the data and the paging message are directed to only the radio device, and compiling the paging message comprises piggybacking the data in a paging record portion of the compiled paging message.

8. The method according to claim 6, in which the data is to be sent to a plurality of radio devices, and compiling the paging message comprises piggybacking the data in at least one information element of the paging message.

9. The method according to any one of claims 6 through 9, in which the method is executed by at least one of an access node of a radio access network and a node of a core network, and compiling the paging message comprises addressing the paging message to a radio network temporary identifier which was first assigned to the radio device by the access node upon an initial access of the radio device to the radio access network.

10. The method according to claim 9, in which the data is a machine type communication which the access node or node of the core network receives for forwarding to the radio device which is a machine-to-machine communication device.

1 1. A computer readable memory tangibly storing a computer program which is executable by at least one processor, in which the computer program comprises:

code for determining that there is data to be sent to a radio device which is not in a connected state; and

code for compiling a paging message, directed to the radio device, which includes the data.

12. The computer readable memory according to claim 1 1 , in which either:

the code for compiling the paging message comprises code for piggybacking the data in a paging record portion of the compiled paging message for the case that the data and the paging message are directed to only the radio device; or

the code for compiling the paging message comprises piggybacking the data in at least one information element of the paging message for the case that the data is to be sent to a plurality of radio devices,

13. The computer readable memory according to any one of claims 1 1 through 12, in which the data is a machine type communication and the radio device is a machine- to -machine communication device.

14. An apparatus, comprising:

receive at a lower protocol layer of the apparatus a paging message with piggybacked downlink data, and separate the data from the paging message; and

forward the separated data from the lower protocol layer to a higher protocol layer of the apparatus for processing.

15. The apparatus according to claim 14, in which the lower protocol layer is a radio resource control layer and the higher protocol layer is a network access stratum layer.

16. The apparatus according to claim 15, in which the piggybacked downlink data is in one of a paging record portion or an information element of the paging message received at the lower protocol layer.

17. The apparatus according to any one of claims 14 through 16, in which the paging message received at the lower protocol layer is addressed to a radio network temporary identifier which was first assigned to the apparatus by a network access node of a radio access network upon an initial access of the apparatus to the radio access network.

18. The apparatus according to claim 17, in which the paging message with the piggybacked downlink data is a machine type communication and the apparatus comprises a machine-to-machine radio communication device.

19. A method comprising: receiving at a lower protocol layer of an apparatus a paging message with piggybacked downlink data, and separating the data from the paging message; and forwarding the separated data from the lower protocol layer to a higher protocol layer of the apparatus for processing.

20. The method according to claim 14, in which the lower protocol layer is a radio resource control layer and the higher protocol layer is a network access stratum layer.

21. The method according to claim 20, in which the piggybacked downlink data is in one of a paging record portion or an information element of the paging message received at the lower protocol layer.

22. The method according to any one of claims 19 through 21, in which the paging message received at the lower protocol layer is addressed to a radio network temporary identifier which was first assigned to the apparatus by a network access node of a radio access network upon an initial access of the apparatus to the radio access network.

23. The method according to claim 22, in which the paging message with the piggybacked downlink data is a machine type communication and the apparatus comprises a machine-to-machine radio communication device,

24. A computer readable memory tangibly storing a computer program which is executable by at least one processor, in which the computer program comprises:

code for separating, at a lower protocol layer of an apparatus at which is received a paging message with piggybacked downlink data, the data from the paging message; and

code for forwarding the separated data from the lower protocol layer to a higher protocol layer of the apparatus for processing.

25, The computer readable memory according to claim 24, in which the lower protocol layer is a radio resource control layer and the higher protocol layer is a network access stratum layer.