WO2014110785A1

WO2014110785A1 - Data transmission for low cost mtc devices

Info

Publication number: WO2014110785A1
Application number: PCT/CN2013/070668
Authority: WO
Inventors: Erlin Zeng; Chunyan Gao; Na WEI; Shuang TAN; Wei Bai; Haiming Wang
Original assignee: Broadcom Corporation
Priority date: 2013-01-18
Filing date: 2013-01-18
Publication date: 2014-07-24

Abstract

A user equipment (UE) conducting machine-type communication (MTC) attempts to blindly decode a message it received using a pre-arranged and finite set of transport formats; and sends on an uplink radio resource feedback about the message, wherein the feedback is based on a result of the blind decoding. Each transport format of the pre-arranged set comprises a unique combination of modulation and coding scheme, physical resource block set;, and number of transmit repetitions. Prior to the message the pre-arranged set may be indicated to the UE in wireless signaling, or it may be specified in a radio standard. The set may be designated for downlink messages and a second set designated for uplink messages. Various embodiments are described for the uplink radio resource on which the feedback is sent, and conventional HARQ feedback is adapted for MTC in these teachings.

Description

DATA TRANSMISSION FOR LOW COST MTC DEVICES

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 data transmissions and related feedback for user devices, including low cost machine-type communication MTC devices, having a relatively large latency requirement for data communications. BACKGROUND:

[0002] One focus of recent research concerning radio communications concerns machine-type communications (MTC), in which radio devices wirelessly transmit data to and/or receive data from a network without the specific direction of people. For example, an electrical utility may utilize remote MTC devices to report current, voltage and other parameters at each of multiple electrical poles or other transmission junctions. Each MTC device can internally log a variety of measurements and report them as a batch at occasional intervals, or when some safety parameter is exceeded. In practice there may be hundreds or even thousands of such sensors in such an environment that are reporting their data to a single network access node.

[0003] Due to the potentially large number in a given deployment, the MTC devices are often assumed to be low cost and thus are sometimes assumed to have a single radio antenna and operate on a reduced bandwidth. This means these MTC devices cannot engage in certain radio-efficient techniques such as frequency diversity gain and frequency selective scheduling gain. In the very low signal to noise ratio (SINR) environment of MTC this leads to a coverage loss which must be compensated in other ways to ensure the radio communications remain reliable.

[0004] One compensation is to improve coverage by up to 20dB per channel (for a frequency division duplex FDD deployment) as compared to what is defined in evolved Universal Terrestrial Radio Access Network (E-UTRAN, also known as long term evolution or LTE) for the cell coverage footprint as engineered for "normal LTE UEs" (assuming deployment in the same spectrum bands). Figure 1 reproduces table 9.2.1-1 from TR 36.388 which summarizes some of the MCL for category 1 UEs from Table 5.2.1.2-2 and Table 5.2.1.2-3 in Section 5.2.1.2 of TR 36.888, with units in dB.

[0005] Another feature of the MTC UE deployment for the LTE- Advanced (LTE- A) system is that the data volume is excepted to be relatively low and the data latency requirements are quite relaxed as compared to conventional LTE voice and data protocols. Specifically, MTC payload size is to be on the order of 100 bytes/message in uplink/UL and 20 bytes/message in downlink/DL, and allowable latency can be up to 10 seconds for DL and up to 1 hour in UL, with 5 seconds allowed for exception reports. See for example document Rl- 125406 by Huawei and HiSilicon entitled TEXT

PROPOSAL FOR TR 36.888 TO ALIGN WITH THE UPDATED SID ON LOW COST MTC.

[0006] The teachings below are useful in, but not limited to, arranging data communications in the low cost MTC environment to meet the above coverage enhancements, and even providing better latency performance and resource efficiency than legacy LTE mechanisms.

SUMMARY:

[0007] In a first exemplary aspect of the invention there is a method for controlling a user equipment (UE) to conduct machine-type communication (MTC). In this aspect the method comprises: attempting to blindly decode a message received at the user equipment (UE) using a pre-arranged and finite set of transport formats; and sending on an uplink radio resource feedback about the message, wherein the feedback is based on a result of the blind decoding.

[0008] In a second exemplary aspect of the invention there is an apparatus for controlling a user equipment to conduct machine-type communication (MTC). In this aspect the apparatus comprises a processing system, and the processing system comprises at least one processor and a memory storing a set of computer instructions. The processing system is configured to cause the apparatus to at least: attempt to blindly decode a message received at the user equipment (UE) using a pre-arranged and finite set of transport formats; and send on an uplink radio resource feedback about the message, wherein the feedback is based on a result of the blind decoding.

[0009] In a third exemplary aspect of the invention there is a computer readable memory tangibly storing a set of computer executable instructions for controlling a user equipment (UE) to conduct machine-type communication (MTC). In this aspect the set of computer executable instructions comprises: code for attempting to blindly decode a message received at the user equipment (UE) using a pre-arranged and finite set of transport formats; and code for sending on an uplink radio resource feedback about the message, wherein the feedback is based on a result of the blind decoding.

[0010] These and other aspects are detailed below with more particularity.

BRIEF DESCRIPTION OF THE DRAWINGS :

[001 1 ] Figure 1 reproduces information from tables 5.2.1.2-2 and 5.2.1.2-3 of document 3GPP Technical Report TR 36.888 quantifying per channel performance improvements required for low cost machine-type communication user equipments.

[0012] Figure 2 is a high level schematic diagram of a MTC radio environment in which embodiments of these teachings can be practiced to advantage.

[0013] Figure 3 is a logic flow diagram that illustrates a method for operating a user equipment/UE for conducting MTC communications, and a result of execution by an apparatus of a set of computer program instructions embodied on a computer readable memory for operating such a UE, in accordance with certain exemplary embodiments of this invention.

[0014] Figure 4 is a simplified block diagram of a UE and a wireless radio network represented by an eNB and by a serving gateway, which are exemplary electronic devices suitable for use in practicing the exemplary embodiments of the invention.

DETAILED DESCRIPTION:

[0015] These teachings concern data communications considering the performance improvements and relaxed latency requirements for LTE MTC, as compared to conventional E-UTRAN/LTE procedures. As a non-limiting example, Figure 2 illustrates an exemplary radio environment in which these teachings may be used to advantage. The examples detailed herein are in the context of the evolved UTRAN (E-UTRAN, sometimes referred to as long term evolution or LTE), but this radio access technology is not limiting to the broader teachings herein. In other deployments these teachings may be utilized with other types of radio access technologies (RATs), including but not limited to LTE-Advanced (LTE-A), Universal Terrestrial Access Radio Network (UTRAN), Global System for Mobile Communications (GSM), Wideband Code Division Multiple Access (WCDMA), and other wireless radio technologies now established or yet to be developed.

[0016] Figure 2 shows that there re periodic reports and exception reports, which are to be under the respective 10 second and 5 second latency requirements noted above. There is a command message which the access node, in this example an IEEE 802.xx/wireless local area network access point WLAN AP, sends to the WLAN module/radio of the MTC UE. The command message instructs the MTC UE to send its logged sensor data and the MTC UE then sends a response as instructed. The following three use cases/scenarios are presented as representative contexts for the type of data messages these teachings can be used to enable.

A) Command-response traffic (triggered reporting) between base station and wireless access node (WAN) module; ~20bytes for command (downlink) & -100 bytes for response (uplink) with a latency of lOseconds from command sent from eNB to response received by eNB. 10 seconds of round trip latency is shared between downlink and uplink message with frequency of daily to monthly. Example use case: Energization status message, Consumer messaging.

B) Exception reported by WAN module; Report (uplink) could be -100 bytes with latency of 3-5 seconds from event at the WAN module. Example use case: Meter alerts (tamper, fire) etc. with frequency of daily to monthly.

C) Periodic reports or keep-alive packets; -100 bytes (uplink) and not sensitive to latency (e.g. tolerance of 1 hour) with frequency of daily to monthly. Example use case: Power (Kw), Volume (gas e.g. m ), Microgeneration read, etc. with frequency of daily to monthly

[0017] For this special scenario, it may not be necessary to use the current data channel (both uplink/UL and downlink/DL) scheduling mechanism. This is because the resource allocation may be rather fixed as compared with normal UEs and so there is less need for the conventional LTE scheduling flexibility. As noted above the MTC data packets are to be much smaller as compared with normal LTE use cases. And there are to be fewer combinations of modulation and coding schemes MCSs to be used in TC data communications due to the more extreme use case still being somewhat limited.

[0018] As compared to the legacy LTE mechanism for scheduling a data channel via the downlink physical control channel PDCCH, there is a need to significantly improve the link performance of both data and control channels for the MTC environment.

[0019] While the above relaxed latency requirements for the MTC UEs with 20dB coverage improvement appear quite long, the low cost MTC devices may be using repetition in their transmissions since they are assumed low cost and not capable of certain conventional cellular techniques to improve throughput. This expected transmission repetition absorbs much of the latency relaxation and so the latency requirements are still very tight. And the repetition of both data and control signaling will occupy a large amount of radio resources and reduce the efficiency of deploying those resources.

[0020] From the above analysis the inventors have concluded that avoiding the control for scheduling and the corresponding repetition should lead to reducing the required latency and greatly improving the resource efficiency. In the teachings below the reader will see that also the delay is reduced; due to extra repetitions for the above coverage improvement the hybrid automatic repeat request (HARQ) feedback delay is much more than in the legacy LTE system. The inventors' own radio simulations have proven that the 5 second/10 second delay requirement is quite challenging, and so these teachings proceed from a simplified grant- transmission mechanism as compared to conventional LTE so as to reduce the delay, particularly for UL transmissions.

[0021 ] According to embodiments of these teachings for low cost MTC there are defined new transmission formats (TFs) which are specific to low cost MTC users with the coverage enhancement requirement such as that detailed in the background section above. Also detailed below is how to define the radio resource which the MTC UE uses for its HARQ feedback, and in this new HARQ process also are described how to handle any message re-transmissions. [0022] Firstly there is a set of pre-defined TFs for the DL MTC transmissions. These may be pre-defined via some previous signaling between the access node and the MTC UE, such as for example in system information or in dedicated signaling when the MTC UE first attaches to the access node (e.g., during the MTC UE's initial access phase). Or alternatively the set of TFs may be specified in a published radio access technology standard and so installed in firmware/hardware in both the access node and the MTC UE. In either case, there can be different sets of TFs for different types of RNTI, e.g., one set of TFs for use with C-RNTI (Cell Radio Network Temporary Identifier), another set of TFs for use with P-RNTI (Paging RNTI), a further set of TFs for use with SI-RNTI (System Information RNTI), etc. These different types of RNTIs are used to generate the scrambling codes for different types of downlink messages, which may have different sizes that are reflected by the different sets of TFs. The TFs are defined by parameters such as for example MCS, a set of physical resource blocks, and a number of transmission repetitions. If a TF has different resources in different subframes, the TF definition will also capture further how the radio resources change over time, such as for example when they change according to a hopping sequence/pattern.

[0023] The MTC UE first begins monitoring for the downlink TFs, and applies the uplink transmission according to the defined uplink TFs, for example after the MTC UE attaches to the access node via a random access channel (RACH) procedure. At that time there is no timing ambiguity between the MTC UE and the network access nodes since the UE gets synchronized during the RACH procedure (via system information or RACH messages) and the system frame number SFN is re-set to zero. So for example the downlink transmission formats within the pre-defined set can be aligned in the time domain to then SFN since proper blind detection relies on both the network and the UE having a common understanding of the starting position. [0024] Secondly, to decode the downlink message sent by the access node the MTC UE blindly searches through the pre-defined set of all the possible TFs. In one specific but non-limiting embodiment the UE will try to use its assigned identifier UE-ID to de-scramble the received bit sequences as is known in the wireless arts (see for example 3GPP TS 36.211). If the downlink message is for this UE then the bits will be scrambled with this UE-ID and the UE can descramble and decode them, otherwise the UE will be de-scrambling with an incorrect UE-ID and the message will not pass its cyclic redundancy check CRC (see for example 3GPP TS 36.212). The MTC UE will attempt this descramble and decode for each successive TF in the pre-defined set, until either the MTC UE is able to successfully decode the message or there are no further TFs in the set for further decode attempts.

[0025] In case the pre-defined set of TFs is too large (the whole pre-defined set being stipulated in a wireless specif8ication or broadcast in system information, for example), in a particular embodiment the network can define a restriction to that whole TF set on a per-UE basis, such as via signaling in a message during the MTC UE's initial access procedure using the RACH or dedicated radio resource control RRC signaling. This technique enables the network to more closely limit any given UE's blind detection burden and thereby save the UE's processing effort and battery power. [0026] Thirdly, for the UE's HARQ feedback the radio resource (which in the LTE type system is a physical uplink control channel PUCCH or a physical uplink shared channel PUSCH) is in one embodiment pre-defined in a semi static way (for example system information or radio resource management RRM signaling), or in another embodiment the HARQ radio resource can be linked or otherwise mapped from the TF which is used for the DL message. So for example assume there is an integer number M of pre-defined TFs for the downlink. In one embodiment there are M PUCCH radio resources for HARQ feedback that are semi- statically reserved and each is linked to one of the M TFs. In another embodiment there is one PUCCH resource assigned per UE and in this one PUCCH resource there are M HARQ-bits corresponding to the M possible TFs. In this latter embodiment only one out of the total M bits can be set to ACK (maximally). [0027] Finally, if the UE detects a transport block (TB) in a certain TF, it will then send an acknowledgement (ACK) in the corresponding UL feedback field. If the UE does not detect any transport block in any of the TFs it tries for the decoding, the UE will send a discontinuous transmission indicator DTX in the UL feedback channel/resource. In one embodiment there is no combining of (partially) decided data as between the original/first transmission and the first (or second) re-transmission of the same transport block.

[0028] Consider a more specific example of the HARQ feedback for a downlink message. From the perspective of the UE it is not possible to differentiate between a TF that contains no date transmission (blank) and a TF that contains a data transmission but for which the UE's CRC check failed due to noise. For this reason, if there is to be any re-transmission by the network it would not be appropriate for the UE to combine the original message which it may have partially decoded with any re-transmitted message which it may have partially or fully decoded. Such HARQ combining is typical in conventional LTE practice, but is not used in this embodiment of the invention. Instead, in this embodiment the UE only sends an ACK when it correctly detects a TB within a TF of the pre-defined set, and will transmit a DTX in the uplink if it sees that all the TFs are blank. [0029] For the case in which the network access node does not detect any feedback, or if it detects only negative acknowledgements (NACKs), then network may send the data again in the next window. But in this embodiment with no HARQ combining there is no way that the UE can combine the data received in adjacent windows. ACK to NACK error is difficult to address and so the solution in this embodiment is to forward the data to a higher layer (layer 2) and the error will be handled there. Neither the UE nor the network access node is able to differentiate between a blank frame and a frame with data that failed the CRC due to noise. So the UE will send a NACK if the TF is not correctly received/decoded. [0030] There is another error to consider in the HARQ process; the UE sends an ACK which the network incorrectly decodes as a NACK. In this case the network will simply send the packet again since it thinks the data was Knack's, and the UE will decode it again and forward the data to layer 2 (L2) if it that data has been corrected.

[0031 ] In an embodiment of these teachings the whole HARQ feedback mechanism can be switched ON or OFF. This gives more flexibility for the transmissions to stay within the latency requirements described above. If switched OFF then the MTC UE never transmits any HARQ-feedback, and all re-transmissions will be based on higher logical layers. If switched ON, then the network shall configure the UL resources for this feedback. For example, if a data packet is segmented to several transport blocks TBs in the physical layer, with HARQ feedback it is possible for the network access node to send again a certain TB out of all of the sent TBs if that certain TB was not correctly received. But if the data packet is only segmented into a single TB in the physical layer, the HARQ feedback is not critical even though it can be used for adjusting the TF selection. In the latter case, higher layer re-transmission can be used for the same purpose. [0032] The above procedures for the downlink can also be used for uplink data transmissions. For example, if the MTC UE is allowed to transmit data in the uplink, a set of TFs for uplink can be predefined or indicated to the UE by higher layer signaling. The pre-defined set of uplink TFs need not be the same as the pre-defined set of downlink TFs, but for flexibility a) any one or more of the TFs that are designated for downlink may also be within the (second) set of TFs that are designated for uplink, or b) in another embodiment the uplink and downlink sets of TFS may be mutually exclusive. If multiple possible TFs for uplink are indicated, the UE can select one out of all of the pre-defined set of TFs for uplink data transmissions for any given data report. The network access node would then similarly use blind detection to decode the data it received from the MTC UE. In some embodiments the network can avoid multiple UEs using the same uplink TF at the same time in order for the network to be able to distinguish which is the sending UE for any given TF. The HARQ design for the uplink data transmission would then be similar as detailed above for downlink data transmissions, except for the HARQ ACK/NACK information may be conveyed on a physical HARQ indicator channel (PHICH or evolved PHICH/ePHICH) if such a HARQ radio resource is specifically defined for MTC use during the development of the LTE-related radio standards for MTC purposes.

[0033] Figure 3 presents a summary of the above teachings for controlling and/or for operating a user equipment (UE) for conducting machine type communications MTC. At block 302 the UE attempts to blindly decode a message that it received, and this blind decoding attempt uses a pre-arranged (and finite) set of transport formats. At block 304 the UE sends, on an uplink radio resource, feedback about the message such that the feedback is based on a result of the blind decoding; that is to say an ACK, NACK or DTX indication. As noted in the detailed examples above the pre-arranged set of transport formats may in an embodiment be indicated in signaling that the UE wirelessly receives prior to the message of block 302, or the set may be specified in a radio standard.

[0034] Block 306 summarizes the above-detailed more restricted set for the UE' s blind decoding. In this case the pre-arranged set stated at block 302 is the more restricted set, and this more restricted set is what is indicated to the UE via wireless signaling the UE receives. This restricted set is itself a subset of a larger group of transport formats that are reserved for machine-type communications (MTC). As above that larger group may be set forth in a radio standard.

[0035] Block 308 describes how the different transport formats (TFs) of the pre-arranged or pre-defined set may be distinguished from one another. There it summarizes that each TF of the pre-arranged set comprise a unique combination of: modulation and coding scheme (MCS); physical resource block (PRB) set; and number of N transmit repetitions. For example, the integer number N may represent how many times the data is repeated in the message that the UE is attempting to decode. As noted above, since the MTC UEs are assumed to be low cost and thus incapable of certain error control techniques such as spatial diversity, one way to help avoid NACKs and re-transmissions of the entire message is to repeat the data multiple times in a same message. As noted above, for the case in which a TF spans more than one subframe at least that TF is also defined by how it spans those subframes, such as by a frequency hopping pattern.

[0036] Certain aspects of the invention detailed above concerned HARQ feedback, and in these teachings the HARQ feedback of block 304 is sent on a physical uplink channel such as a physical uplink control channel PUCCH or a physical uplink shared (data) channel PUSCH that is pre-defined for the UE via wireless signaling.

[0037] Two distinct embodiments concerning the feedback radio resource are summarized at block 310. In both embodiments there are a total integer number of M pre-arranged transport formats in the set. In one embodiment there is exactly one uplink radio resource reserved for feedback and that one resource has a total of M bits specified for the feedback. In this embodiment the actual feedback stated in block 304 of Figure 3 is an acknowledgement/ ACK and is sent in only one of the M bits of the uplink radio resource, and that one bit corresponds to a specific TF of the set which the UE used to decode the received message. In the other embodiment summarized at block 310 there are a total of M uplink radio resources reserved for feedback, and the uplink radio resource on which the block 304 feedback is sent is a physical uplink channel (PUCCH or PUSCH) that is linked to a specific TF of the set which the UE used to decode the received message.

[0038] For the case in which the HARQ feedback is a NACK then the message of block 302 may be considered as a first message, in which case then there is the further step of the UE decoding a second message received in a next window following that NACK feedback, and the second message comprises re-transmitted data of the first message. The UE's decoding of the second message, blind or otherwise, does not utilize any combining with the first message which the UE may or may not have partially decoded.

[0039] For all of the above HARQ specific teachings, the sending of the feedback on the uplink radio resource of at block 304 is conditional on HARQ-feedback being switched ON, since in some embodiments it may be switchable rather than always-on as in conventional LTE. [0040] Applying the above downlink teachings also to the uplink, assume that also the UE has data to send uplink. In this case then block 312 summarizes the additional UE actions in that it selects one transport format from among a second pre-arranged set of transport formats for uplink, and the UE sends an uplink data message using the selected one transport format.

[0041 ] In the above non-limiting example embodiments the pre-arranged set of transport formats from block 302 is specific for downlink machine-type communications, and the UE wirelessly sends the feedback using LTE- Advanced radio access technology.

[0042] The logic diagram of Figure 3 may be considered to illustrate the operation of a method, and a result of execution of a computer program stored in a computer readable memory, and a specific manner in which components of an electronic device are configured to cause that electronic device to operate, whether such an electronic device is an MTC UE or some other portable electronic device that is exchanging data messages with its access node/eNB, or one or more components thereof such as a modem, chipset, or the like. The various blocks shown in Figure 3 may also be considered as a plurality of coupled logic circuit elements constructed to carry out the associated function(s), or specific result of strings of computer program code or instructions stored in a memory.

[0043] Such blocks and the functions they represent are non-limiting examples, and may be practiced in various components such as integrated circuit chips and modules, and that 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.

[0044] Such circuit/circuitry embodiments include any of the following: (a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and (b) combinations of circuits and software (and/or firmware), such as: (i) a combination of processor(s) or (ii) portions of processor(s)/software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a user equipment/UE/MTC UE, to perform the various functions summarized at Figure 5 and (c) circuits, such as a microprocessor(s) or a portion of a microprocessor(s), that require software or firmware for operation, even if the software or firmware is not physically present. This definition of 'circuitry' applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term "circuitry" would also cover an implementation of merely a processor (or multiple processors) or portion of a processor and its (or their) accompanying software and/or firmware. The term "circuitry" also covers, for example, a baseband integrated circuit or applications processor integrated circuit for a user equipment UE or for a network access node/eNB or a similar integrated circuit in a server or other network device which operates according to these teachings.

[0045] Reference is now made to Figure 4 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 4 an eNB 22 is adapted for communication over a wireless link 21 with an apparatus, such as a mobile terminal or MTC UE 20. The eNB 22 may be any access node (including frequency selective repeaters) of any wireless network such as LTE, LTE-A, GSM, GERAN, WCDMA, and the like. The operator network of which the eNB 22 is a part may also include a network control element such as a mobility management entity MME and/or serving gateway SGW 24, or radio network controller RNC in the case of a UTRAN, either of which provide connectivity with the core cellular network and with further networks (e.g., a publicly switched telephone network PSTN and/or a data communications network/Internet) .

[0046] The MTC UE 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, and communication 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 stored in the MEM 20B at reference number 20G are the algorithms or look-up tables which enable the MTC UE 20 to attempt to blindly decode received downlink messages using a pre-arranged set of transport formats which are stored in the MEM 20B of the UE 20 according to previous signaling or radio standard specifications as detailed in the various embodiments described in further detail above. Similarly there are algorithms or tables for defining where exactly is the feedback resource and/or bit position for the appropriate HARQ feedback as described above in various examples.

[0047] 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, and communication 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. The eNB 22 may also have a direct interface 23 with other adjacent eNBs. The eNB 22 stores at block 22G its own algorithms/look-up tables which set forth the set of TFs to be used for MTC and the eNB 22 uses only those TFs to send downlink data to the MTC UE, as detailed above with particularity.

[0048] For completeness, Figure 4 also shows high level details of the serving gateway SGW 24, including 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, and communication means such as a modem 24H for bidirectional wireless communications with the eNB 22 via a data/control link 25.

[0049] While not particularly illustrated for the UE 20 or the access node/eNB 22, those devices are also assumed to include as part of their wireless communicating means a modem and/or a chipset which may or may not be inbuilt onto a radiofrequency RF front end chip within those devices 20, 22, and which may also operate according to the specific non-limiting examples set forth above.

[0050] At least one of the PROGs 20C in the UE 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 also has software stored in its MEM 22B to implement certain aspects of these teachings as detailed further 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 20 A of the UE 20 and/or by the DP 22A of the eNB 22; or by hardware, or by a combination of tangibly stored software and hardware (and tangibly stored firmware) in any one or more of these devices 20, 22. Electronic devices implementing these aspects of the invention need not be the entire devices as depicted at Figure 4 or may be one or more components of same such as the above described tangibly stored software, hardware, firmware and DP, or a system on a chip SOC or an application specific integrated circuit ASIC.

[0051 ] In general, the various embodiments of the UE 20 can include, but are not limited to personal portable digital devices having wireless communication capabilities, including but not limited to cellular and other mobile telephones, navigation devices, laptop/palmtop/tablet computers, digital cameras and music devices, and Internet appliances. The MTC UE device may also be embodied as a radio device having inputs from a sensor such as a pole-mounted or meter-mounted radio that records and reports electrical parameters in a smart-grid deployment, or in an industrial or agricultural deployment in which the MTC radio device records and reports environmental and/or process conditions. Other possible deployments for MTC devices include vehicles such as ships, airplanes and cars to monitor and report information on systems and environmental conditions; and urban areas to record and report traffic conditions in real time. There are many others. These widely varying deployments mean that MTC devices can take a wide variety of forms and so they are defined more by their radio functionality than their physical embodiment.

[0052] Various embodiments of the computer readable MEMs 20B, 22B 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 include but are not limited to general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and multi-core processors.

[0053] 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 LTE/LTE-A system, as noted above the exemplary embodiments of this invention are not limited for use with only these particular types of wireless radio access technology networks and can also be deployed in UTRAN and WLAN systems, among others.

[0054] 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

WHAT ID CLAIMED IS:

1. A method for controlling a user equipment (UE) to conduct machine-type communication (MTC), comprising:

attempting to blindly decode a message received at the user equipment (UE) using a pre-arranged and finite set of transport formats; and

sending on an uplink radio resource feedback about the message, wherein the feedback is based on a result of the blind decoding.

2. The method according to claim 1, wherein:

the pre-arranged set of transport formats is indicated in signaling wirelessly received at the UE prior to the message or is specified in a radio standard.

3. The method according to claim 2, wherein the pre-arranged set is a restricted set indicated in the signaling that is wirelessly received at the UE, wherein the restricted set is a subset of a larger group of transport formats that are reserved for machine-type communications (MTC).

4. The method according to any of claims 1-3, wherein each transport format of the pre-arranged set comprises a unique combination of:

modulation and coding scheme (MCS);

physical resource block (PRB) set; and

number of transmit repetitions N.

5. The method according to claim 4, wherein each of the transport formats having radio resources that span more than one subframe is defined by a hopping pattern.

6. The method according to any of claims 1-5, wherein the uplink radio resource on which the feedback is sent is a physical uplink channel that is pre-defined via wireless signaling.

7. The method according to any of claims 1-6, wherein there are a total integer number of M pre-arranged transport formats in the set and one uplink radio resource reserved for feedback and having a total of M bits specified for the feedback, and the feedback is an acknowledgement and is sent in only one of the M bits of the uplink radio resource which corresponds to a specific transport format of the set which the user equipment used to decode the received message.

8. The method according to any of claims 1-6, wherein there are a total integer number of M pre-arranged transport formats in the set and M uplink radio resources reserved for feedback, and the uplink radio resource on which the feedback is sent is a physical uplink channel that is linked to a specific transport format of the set which the user equipment used to decode the received message.

9. The method according to any of claims 7-8, wherein the message is a first message and for the case in which the feedback is a negative acknowledgement, the method further comprising:

decoding a second message received in a next window following the feedback, the second message comprising re-transmitted data of the first message, and the decoding of the second message does not utilize combining with the first message.

10. The method according to any of claims 1-9, wherein the feedback about the message is sent on the uplink radio resource conditional on HARQ-feedback being switched on.

11. The method according to any of claims 1-10, the method further comprising: the user equipment selecting one transport format from among a second pre-arranged set of transport formats for uplink and sending an uplink data message using the selected one transport format.

12. The method according to any of claims 1-11, wherein the pre-arranged set of transport formats said in claim 1 is specific for downlink machine-type communications and the UE wirelessly sends the feedback using LTE or LTE- Advanced radio access technology.

13. The method according to any of claims 1-12, wherein the method is performed by the UE which is a mobile phone.

14. An apparatus for controlling a user equipment (UE) to conduct machine-type communication (MTC), the apparatus comprising a processing system which comprises at least one processor and a memory storing a set of computer instructions, the processing system configured to cause the apparatus to at least:

attempt to blindly decode a message received at the user equipment (UE) using a pre-arranged and finite set of transport formats; and

send on an uplink radio resource feedback about the message, wherein the feedback is based on a result of the blind decoding.

15. The apparatus according to claim 14, wherein the pre-arranged set of transport formats is indicated in signaling wirelessly received at the UE prior to the message or is specified in a radio standard.

16. The apparatus according to claim 15, wherein the pre-arranged set is a restricted set indicated in the signaling that is wirelessly received at the UE, wherein the restricted set is a subset of a larger group of transport formats that are reserved for machine-type communications (MTC).

17. The apparatus according to any of claims 14-16, wherein each transport format of the pre-arranged set comprises a unique combination of:

modulation and coding scheme (MCS);

physical resource block (PRB) set; and

number of transmit repetitions N.

18. The apparatus according to claim 17, wherein each of the transport formats having radio resources that span more than one subframe is defined by a hopping pattern.

19. The apparatus according to any of claims 14-18, wherein the uplink radio resource on which the feedback is sent is a physical uplink channel that is pre-defined via wireless signaling.

20. The apparatus according to any of claims 14-19, wherein there are a total integer number of M pre-arranged transport formats in the set and one uplink radio resource reserved for feedback and having a total of M bits specified for the feedback, and the feedback is an acknowledgement and is sent in only one of the M bits of the uplink radio resource which corresponds to a specific transport format of the set which the user equipment used to decode the received message.

21. The apparatus according to any of claims 14-19, wherein there are a total integer number of M pre-arranged transport formats in the set and M uplink radio resources reserved for feedback, and the uplink radio resource on which the feedback is sent is a physical uplink channel that is linked to a specific transport format of the set which the user equipment used to decode the received message.

22. The apparatus according to any of claims 18-19, wherein the message is a first message and for the case in which the feedback is a negative acknowledgement, and the processing system is configured to cause the apparatus further to:

decode a second message received in a next window following the feedback, the second message comprising re-transmitted data of the first message, and the decoding of the second message does not utilize combining with the first message.

23. The apparatus according to any of claims 14-22, wherein the feedback about the message is sent on the uplink radio resource conditional on HARQ-feedback being switched on.

24. The apparatus according to any of claims 14-23, wherein the processing system is configured to cause the apparatus further to:

select one transport format from among a second pre-arranged set of transport formats for uplink and send an uplink data message using the selected one transport format.

25. The apparatus according to any of claims 14-24, wherein the pre-arranged set of transport formats said in claim 13 is specific for downlink machine-type communications and the UE wirelessly sends the feedback using LTE or LTE- Advanced radio access technology.

26. The apparatus according to any of claims 14-25, wherein the apparatus is the UE which is a mobile phone.

27. A computer readable memory tangibly storing a set of computer executable instructions for controlling a user equipment (UE) to conduct machine-type communication (MTC), the set of computer executable instructions comprising:

code for attempting to blindly decode a message received at the user equipment

(UE) using a pre-arranged and finite set of transport formats; and

code for sending on an uplink radio resource feedback about the message, wherein the feedback is based on a result of the blind decoding.

28. The computer readable memory according to claim 27, wherein the pre-arranged set of transport formats is indicated in signaling wirelessly received at the UE prior to the message or is specified in a radio standard.

29. The computer readable memory according to claim 28, wherein the pre-arranged set is a restricted set indicated in the signaling that is wirelessly received at the UE, wherein the restricted set is a subset of a larger group of transport formats that are reserved for machine-type communications (MTC).

30. The computer readable memory according to any of claims 27-29, wherein each transport format of the pre-arranged set comprises a unique combination of:

modulation and coding scheme (MCS);

physical resource block (PRB) set; and

number of transmit repetitions N.

31. The computer readable memory according to claim 30, wherein each of the transport formats having radio resources that span more than one subframe is defined by a hopping pattern.

32. The computer readable memory according to any of claims 27-31, wherein the uplink radio resource on which the feedback is sent is a physical uplink channel that is pre-defined via wireless signaling.

33. The computer readable memory according to any of claims 27-32, wherein there are a total integer number of M pre-arranged transport formats in the set and one uplink radio resource reserved for feedback and having a total of M bits specified for the feedback, and the feedback is an acknowledgement and is sent in only one of the M bits of the uplink radio resource which corresponds to a specific transport format of the set which the user equipment used to decode the received message.

34. The computer readable memory according to any of claims 27-32, wherein there are a total integer number of M pre-arranged transport formats in the set and M uplink radio resources reserved for feedback, and the uplink radio resource on which the feedback is sent is a physical uplink channel that is linked to a specific transport format of the set which the user equipment used to decode the received message.

35. The computer readable memory according to any of claims 33-34, wherein the message is a first message and for the case in which the feedback is a negative acknowledgement, the set of computer executable instructions further comprising: code for decoding a second message received in a next window following the feedback, the second message comprising re-transmitted data of the first message, such that the decoding of the second message does not utilize combining with the first message.

36. The computer readable memory according to any of claims 27-35, wherein the feedback about the message is sent on the uplink radio resource conditional on HARQ-feedback being switched on.

37. The computer readable memory according to any of claims 27-36, the set of computer executable instructions further comprising:

code for selecting one transport format from among a second pre-arranged set of transport formats for uplink, and for sending an uplink data message using the selected one transport format.

38. The computer readable memory according to any of claims 27-37, wherein the pre-arranged set of transport formats said in claim 27 is specific for downlink machine-type communications and the UE wirelessly sends the feedback using LTE or LTE- Advanced radio access technology.