WO2013082784A1

WO2013082784A1 - Resource allocation by component carrier sub-bands

Info

Publication number: WO2013082784A1
Application number: PCT/CN2011/083700
Authority: WO
Inventors: Chunyan Gao; Erlin Zeng; Jing HAN; Haiming Wang; Wei Hong; Wei Bai
Original assignee: Renesas Mobile Corp
Current assignee: Renesas Electronics Corp
Priority date: 2011-12-08
Filing date: 2011-12-08
Publication date: 2013-06-13
Anticipated expiration: 2014-06-08

Abstract

A user equipment UE is signaled to utilize a second format for downlink control information as opposed to a first format. Resources allocated by the first format are not bandwidth-restricted respecting a carrier and resources allocated by the second format are restricted to a subset of bandwidth sub-bands. The UE is then scheduled on resources that are restricted to the subset of sub-bands using the second format. In various specific embodiments the sub-bands are defined by predetermined static frequency bounds for the UE specifically or for the entire cell; the sub-bands may be defined by a predetermined algorithm which identifies a sub-band index as a function of UE identity, system frame number, and/or a number of sub-bands which are in the subset. The second format has a resource allocation field whose length depends on how many physical resource blocks are in the sub-bands and therefore in the subset.

Description

RESOURCE ALLOCATION BY COMPONENT CARRIER SUB-BANDS

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 arranging spectrum such that a user equipment's resource allocations lie only within a subset of the whole bandwidth of a component carrier, and efficient signaling to take advantage of that restricted subset.

BACKGROUND:

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

3 GPP third generation partnership project

CA carrier aggregation

CC component carrier

CSI channel state information

DCI downlink control information

DL downlink

eNB node B/base station in an E-UTRAN system

E-UTRAN evolved UTRAN (LTE)

LTE long term evolution (of UTRAN)

LTE-A long term evolution-advanced

MTC machine type communications

PCell primary component carrier/primary cell

PDCCH physical downlink control channel

PDSCH physical downlink shared channel

PPvB physical resource block

PUSCH physical uplink shared channel

RBG resource block group

SCell secondary component carrier/secondary cell

SFN subframe number

UE user equipment

UL uplink

UTRAN universal terrestrial radio access network

VRB virtual resource block

[0003] Currently the LTE wireless system (Release 10) specifies in 3GPP TS 36.213 vl0.3.0 that there are three types of resource allocation for the DL data transmission to a cellular UE: types 0, 1 and 2. In resource allocations of type 0, resource block assignment information includes a bitmap indicating the resource block groups (RBGs) that are allocated to the scheduled UE where a RBG is a set of consecutive virtual resource blocks (VRBs) of localized type (see 3GPP TS 36.211 vlO.3.0, section 6.2.3.1). The size (P) of the resource block group is a function of the system bandwidth (see 3 GPP TS 36.211 vlO.3.0, Table 7.1.6.1-1). The total number of RBGs ( N^ ) for downlink system bandwidth of is given by N_RBG = I P \ .

[0004] In resource allocations of type 1, information about the size of a resource block assignment indicates to a scheduled UE the VRBs from the set of VRBs from one of P RBG subsets. And in resource allocations of type 2, the resource block assignment information indicates to a scheduled UE a set of contiguously allocated localized virtual resource blocks or distributed virtual resource blocks. The definition of RBG size is shown in the following table as depending on system bandwidth.

[0005] That same LTE specification defines two types of resource allocations for UL data transmission: types 0 and 1. Type 0 indicates to a scheduled UE a set of contiguously allocated virtual resource block indices, denoted by starting point + length. Type 1 indicates to a scheduled UE two sets of resource blocks with each set including one or more consecutive resource block groups of size P as given in table 7.1.6.1-1 of 3GPP TR 36.213 vlO.2.0 assuming as the system bandwidth.

[0006] Currently in LTE for both DL and UL the required bits for resource allocation increases with the system bandwidth; this allows the eNB the flexibility to select the resource being allocated from the whole carrier band. The carrier band in this case refers to the bandwidth of one component carrier of a carrier aggregation system, shown for example at Figure 1. [0007] In CA the whole system bandwidth is carved into multiple component carriers CCs. While other radio systems also utilize the CA concept, specific for LTE/LTE-A is that each UE is to be assigned one PCell which remains active and one or more SCells which may or may not be active at any given time, depending on data volume for the UE and traffic conditions in the serving cell. At least one CC in the system is to be backward compatible with UE's which are not capable of CA operation. One or more CCs may be extensions carriers whose structure is not yet fully defined but which may or may not have a full or even partial control channel region. [0008] Figure 1 illustrates the general CA concept for LTE/LTE-A. For a given UE there is assigned a PCell 100 which by example is backward-compatible with LTE Release 8/9 UEs (and therefore 20 MHz in bandwidth though the various CCs may be defined by different bandwidths). That same UE may also have in its assigned set SCell#l, SCell#2 and SCell#3, which for completeness SCell#3 is shown as being non-contiguous in frequency with the other CCs. Any number of the SCells or none of them may be active for that UE at any given time, as coordinated with and configured by the eNB. Every UE is to have its assigned PCell always active, and so legacy UEs which are not CA-capable will be assigned one backward-compatible CC and no others.

[0009] For heterogeneous deployments of femto cells within the coverage area of conventional macro cells, the femto cell may operate on one CC while the macro cell operates on the other CCs, or both may share the same CC and avoid collisions by enhanced inter-cell interference coordination. One or more CCs may lie in the license-exempt bands, such as the industrial/scientific/medical (ISM) band and/or television white spaces (TVWS).

[0010] As will be detailed below, the inventors consider it sub-optimal from a signaling efficiency perspective to allow the eNB full flexibility to schedule any of its UEs over the entire bandwidth of a CC. These teachings describe an approach to UE resource allocations that is more efficient from the perspective of control signaling overhead.

[001 1 ] Related teachings include document Rl-113072 by Samsung entitled ENHANCING PDCCH CAPACITY FOR CA THROUGH COMPACT DCI FORMATS (3 GPP TSG RAN WG#1 meeting #66bis; Zhuhai, China; October 10-14, 2011), which provides a compact DCI design to save control overhead of uplink grant. Specifically, the DCI size is reduced by PUSCH size limitation, rendering part of the uplink bandwidth unavailable, and limiting the MCS options. Document Rl-112893 by Huawei entitled ADDITIONAL CARRIER TYPES - MOTIVATIONS AND ISSUES (from the same RAN meeting) also provides some relevant thoughts. SUMMARY:

[0012] In a first exemplary embodiment of the invention there is an apparatus comprising at least one processor and at least one memory storing a computer program. In this embodiment the at least one memory with the computer program is configured with the at least one processor to cause the apparatus to at least: signal a user equipment to utilize a second format for downlink control information as opposed to a first format for downlink control information, in which resources allocated by the first format are not restricted respecting a whole bandwidth of a carrier and resources allocated by the second format are restricted to a subset of sub-bands of the bandwidth; and schedule the user equipment on resources that are restricted to the subset of sub-bands using the second format.

[0013] In a second exemplary embodiment of the invention there is a method comprising: signaling a user equipment to utilize a second format for downlink control information as opposed to a first format for downlink control information, in which resources allocated by the first format are not restricted respecting a whole bandwidth of a carrier and resources allocated by the second format are restricted to a subset of sub-bands of the bandwidth; and scheduling the user equipment on resources that are restricted to the subset of sub-bands using the second format. [0014] In a third exemplary embodiment of the invention there is a computer readable memory tangibly storing a computer program executable by at least one processor, the computer program comprising: code for signaling a user equipment to utilize a second format for downlink control information as opposed to a first format for downlink control information, in which resources allocated by the first format are not restricted respecting a whole bandwidth of a carrier and resources allocated by the second format are restricted to a subset of sub-bands of the bandwidth; and code for scheduling the user equipment on resources that are restricted to the subset of sub-bands using the second format.

[0015] These and other embodiments and aspects are detailed below with particularity.

BRIEF DESCRIPTION OF THE DRAWINGS:

[0016] Figure 1 is a schematic frequency diagram showing a carrier aggregation system in which some component carriers lay in a licensed band and some lay in unlicensed bands.

[0017] Figure 2 illustrates one of the component carriers of Figure 1 divided into sub-bands according to an exemplary embodiment of these teachings.

[0018] Figure 3 is a logic flow diagram that illustrates from the perspective of the network/eNB the operation of a method, and a result of execution of computer program instructions embodied on a computer readable memory, in accordance with an exemplary embodiment of this invention.

[0019] Figure 4 is a simplified block diagram of a UE and an eNB which are exemplary electronic devices suitable for use in practicing the exemplary embodiments of the invention. DETAILED DESCRIPTION:

[0020] The following examples are in the specific context of the LTE/LTE-A systems (for example, Release 1 1 and later) but these teachings are more broadly applicable to any wireless radio system which divides its spectrum into different component carriers and which further employs radio resource grants from the network to the UEs. These examples consider only a single UE but it will be understood the description applies for all such UEs being scheduled for radio resources according to the teachings described for one UE. Additionally, these teachings may be further extended to a machine-to-machine (M2M) type device which uses machine-type communications (MTC) for generally small volume and infrequent data transmissions. Such machine-to-machine type device is included under the more generic term UE or user device to distinguish it from any network node. [0021 ] In the background section above it was detailed that in current procedures for LTE the eNB has full flexibility to allocate to any UE resources anywhere within the target component carrier. This flexibility in resource allocation can improve the UE's throughput only in the case that the eNB has knowledge of the frequency selective CSI of the whole bandwidth. If instead the frequency selective CSI is not available, this flexibility in resource allocation is unnecessary.

[0022] There are several scenarios in which the frequency selective CSI is unavailable:

• Extension carrier where C S bandwidth may be configurable to reduce the reference signal overhead from system level (as detailed at document Rl-112893 referenced above).

• UEs with small packet and intermittent traffic (MTC for example) which will be configured to report a wide band CSI or even which is configured for no CSI to avoid too much overhead for small data transmission.

· UEs with a band filter narrower than the system bandwidth which may need to be configured for a narrow band data transmission (for example, low cost MTC UEs which are contemplated for LTE Release 11).

[0023] Considering that the resource allocation accounts for a large proportion of the DCI overhead, avoiding the resource allocation bits that are unnecessary can help to reduce DCI overhead. This reduced overhead reduces the amount of radio resources required for PDCCHs and/or E-PDCCHs, and further aids in improving the DL control performance. Embodiments of these teachings which are detailed further below provides an improved resource allocation solution which avoids at least some of that unnecessary overhead to yield a more efficient utilization of the spectrum due to the overhead reduction in control bits.

[0024] As will be detailed below there is presented a new design for a new resource allocation, which divides the system bandwidth of one operating component carrier into several frequency sub-bands 202a, 202b, 202c, and so forth as is shown at Figure 2. Figure 2 by example illustrates one component carrier 200 of a carrier aggregation system such as that of Figure 1. While the sub-bands shown at Figure 2 are not overlapping in frequency, in another embodiment some or all of those sub-bands may have some overlapping frequencies. The sub-bands themselves may be pre-defined by specific frequency bounds, or they may be pre-defined by a rule for dividing the carrier 200 such that in different circumstances the same rule will give different frequency bounds for the same sub-bands.

[0025] The sub-bands may each be identified by an index and the sub-band index or indices for one UE's restricted subset does not necessarily require explicit signalling. Instead it can be a function of a rule or algorithm stored in the local memory of the UE and of the eNB so both entities are aware without explicit signaling which sub-bands apply for which UE. For example, if the sub-frames are given as a function of UE-ID or/and subframe number either of the following functions/algorithms may be stored in the UE and in the eNB:

Sub-band index= (UE-ID + subframe number) mod (M); or, Sub-band index=(UE-ID) mod (M) + (subframe number) mod (P);

In the above algorithms, M is the total number of sub-bands, and P is the period for the UE to change the sub-band index. Taking SFN as one parameter makes the assigned sub-band varies with time, which helps to enable a diversity gain for UEs.

[0026] In case multiple sub-bands are configured for a UE, the above rule/algorithm can be used to find the index of one of the sub-bands while the index of other sub-bands in the configured subset can be derived based on that first one, such as by the algorithm below:

Index for the i^th sub-band=index for the 1^st sub-band+offset; where 'offset' is also known in advance by both the UE and the eNB such as a default offset subject to being overridden by network signalling in system information.

[0027] Whether by static frequency bounds or a more dynamic sub-band division rule, the sub-band division can in one embodiment be cell specific or in another embodiment can be specific for a given UE operating in the cell, for example different categories/classes of UEs or UEs with different capabilities can use a different division of the same carrier 200 into sub-bands. The PRBs within the same sub-band 202a, 202b can be distributed or localized in the frequency domain. Figure 2 shows localized PRBs but in another embodiment using distributed PRBs a single sub-band may not be defined by frequency bounds but by a group of PRBs that may or may not be frequency-adjacent. The radio network can configure a given UE to use the whole bandwidth of the component carrier 200 for its resource allocations, or the network can restrict that UE to use a subset of the whole bandwidth. That is, if the whole bandwidth consists of M sub-bands, the network can configure a UE such that its allocated resources lie in only a subset of n sub-bands, where n is less than M and each of n and M are positive integers. For the LTE or LTE-A system in particular, this means that the PDCCH which the eNB sends to a UE configured for the restricted subset of n sub-bands will grant radio resources (PUSCH or PDSCH) which lie only in that restricted set of n sub-bands. This is particularly advantageous for MTC type devices whose data communications are infrequent in time and small in volume, and it is expected that the typical case for such MTC devices will be to configure them for only one sub-band.

[0028] For UEs which are configured to use a restricted sub-band or set of sub-bands, the sub-band(s) that it is to use are in one embodiment derived implicitly and in another embodiment they are derived or signaled explicitly. For example, the sub-bands may be identified by indices and the index of the sub-band(s) configured for a given UE may be a function of the UE's identifier (such as the cell radio network temporary identifier CRNTI assigned by the network), or a function of the system frame number SFN as in the above examples. Or the rule/algorithm to identify the sub-band(s) may be a function of how many sub-bands are configured for the UE (for example, configuring the UE for two sub-bands implicitly configures it for sub-bands 201b and 201c; configuring a UE for five sub-bands implicitly configures it for five specific other sub-bands). These are but three non-limiting examples of implicit derivation of the configured sub-bands. For an explicit indication of the configured sub-band(s) the network can signal to the UE a bitmap, which may be defined by higher layers in the network than the access node/eNB.

[0029] For those UEs which are configured to only use one or multiple sub-band(s), the resource allocation for that UE will only be distributed by the network in that one or multiple configured sub-band(s) and the length of the resource allocation field will depend on the size of the configured sub-bands. The resources that the network allocates to the UE for PUSCH and PDSCH are the PRBs and the sub-bands are where in the whole carrier bandwidth the PRBs lie. The resource allocation field of the DCI indicates which PRBs in the configured n sub-bands are allocated for PUSCH and PDSCH. For example, if there is only one sub-band in the restricted set and four PRBs in that sub-band are configured for a given UE to use, then in the most flexible case the resource allocation field in a DCI will need four bits to identify the resource allocated for the PUSCH/PDSCH. Thus the bit length of the resource allocation field depends on how many PRBs are configured for the UE. To this end the network will retain the option of using either a) a conventional/prior art DCI format which does not restrict where in the component carrier 200 the UE's radio resource allocations might lay, and b) a new DCI format which restricts where in the whole bandwidth the resource allocations might lie. In this new DCI the length of the resource allocation field depends on the value of n and the size of each sub-band, for example the number of sub-bands which are in the restricted space of sub-bands and the number of PRBs in each sub-band. And the network will also use a new DCI format in the cell for those UEs with the restricted sub-band(s). In this case the UE configured for the restricted set of sub-bands will only monitor the new DCI format in its UE-specific search space. In one particular embodiment the network may have the flexibility for some special cases to omit the resource allocation field from the new DCI format, which the UE will interpret that its allocated radio resources are all the PRBs in the configured n sub-bands.

[0030] For example, respecting the UEs which are configured to use such a resource allocation restriction the DCI size for it will be reduced since the RA field requires fewer bits due to the fact that it only selects resources from one or more sub-bands which are a subset of the whole M sub-bands that span the whole bandwidth. Respecting the specific resource allocation within a given sub-band, current resource allocation types can be reused. Or there may be some new allocation which simply identifies which specific resource within the identified sub-band is being allocated.

[0031 ] For UEs which are configured with a subset of n sub-band(s) less than the total bandwidth M sub-bands, CSI reports from those UEs are generated according to an exemplary embodiment of these teachings using only the UE's channel measurements of the n configured sub-band(s). For the case in which the sub-band(s) is/are determined based on the SFN which varies per subframe of the radio transmission frame (with or without also depending on the UE identifier such as the C-R TI), the CSI can be generated based on measurement in the whole bandwidth. For the case in which the sub-band(s) is/are determined based on only on the UE-ID or some other parameter which does not vary, or if the sub-band index changes per period P as in the above example algorithms, the UE can generate its CSI for uplink reporting based on measurement in the current sub-band(s) only.

[0032] The legacy UEs which are not adapted to practice these teachings need not be affected when these teachings are adopted in a cell; those legacy UEs will simply be scheduled with the conventional prior art DCI format, and the network can choose to configure the UEs adapted for these teachings to use either that prior art DCI format or to use the new DCI format. The network may make this decision based on current conditions in the cell; when it is not congested the eNB may prefer the flexibility of having its resource allocations for all UEs unrestricted, but when traffic becomes congested the UE may choose to save on control signalling overhead by restricting resources allocated to some UEs to one or more sub-bands and configure those UEs to use the new DCI format. Without loss of generality, consider the prior art DCI format a first DCI format for which the resource allocations are not restricted respecting the whole component carrier 200 bandwidth (that is, unrestricted as to the M sub-bands which make up the whole bandwidth), and consider the new DCI format a second DCI format for which the resource allocations are restricted to only n sub-bands of the whole M-sub-band bandwidth of the component carrier 200, where n is less than M. Signaling from the network/eNB enables this distinction as to which UE is to monitor for which DCI type, as each UE needs to monitor only for either the first or second DCI type, not both at the same time. [0033] For example, the network will indicate whether the above resource allocation restriction in sub-band(s) is to be configured or not for a UE. This signalling may be an indication of the number of sub-bands to be used, or which sub-band(s) is/are allocated. Or there may be a single bit indicating whether the resource allocation restriction is configured for the UE and the above signalling of the number and/or which sub-bands are to be used for the restricted resource allocation is in addition to that single bit. This is an example of UE specific signalling, for embodiments such as the above examples where the configuration is based on the UE category, traffic type, UE position, link quality to eNB, or any combination of two or more of those examples. [0034] As for the sub-bands, in one embodiment no explicit signalling is needed since in this embodiment the sub-bands are predefined and known to both eNB and UE. For example, the whole bandwidth may be divided into M sub-bands and this division is operative for all the UEs which have the sub-band restriction and which use the second DCI format. In another example the sub-band restriction is based on the UE capability (UE class) and the sub-band division is UE specific rather than cell-wide. So for example those UEs which support 5MHz transmission, the whole band is divided into some 5MHz sub-bands; whereas for UEs which support 1.4MHz transmission, the whole band is divided into some 1.4MHz sub-bands. In this example the division rules may still be predefined.

[0035] Embodiments of the invention detailed above provide certain technical effects such as for example saving unnecessary DL control overhead for extension carrier UEs or MTC UEs. The reduced resource allocation overhead means a reduced DCI overhead which lead to improved resource efficiency.

[0036] Further technical effects are that these teachings enable operation in the network by low cost MTC UEs which may have only a narrow radiofrequency F filter. Also, randomizing the sub-band allocation such as by UE identifier and/or SFN obtains an advantageous frequency diversity, and for those UEs sending and receiving their data only in the subset of sub-bands their CSI reports are reduced in volume (since they are reporting only on the subset of sub-bands rather than the whole bandwidth) and are more accurate.

[0037] Now are detailed with reference to Figure 3 further particular exemplary embodiments from the perspective of the network/eNB. Figure 3 may be performed by the whole eNB, or by one or several components thereof such as a modem. At block 302 the eNB signals a UE to utilize a second format for DCI as opposed to a first format for DCI, in which resources allocated by the first format are not restricted respecting a whole bandwidth of a carrier and resources allocated by the second format are restricted to a subset of sub-bands of the bandwidth. Then at block 304 the eNB schedules the UE on resources that are restricted to the subset of sub-bands using the second format. [0038] Further portions of Figure 3 represent several of the specific but non-limiting embodiments detailed above. Block 306 provides further detail that the sub-bands are defined by predetermined static frequency bounds, such as may be standardized in a wireless protocol or indicated by the eNB in system information (cell-wide signaling) or which may be specifically signaled to the individual UE of block 302 (UE-specific signaling).

[0039] Block 308 summarizes the alternate embodiment as compared to block 306, namely that the sub-bands are defined by a predetermined algorithm which identifies a sub-band index as a function of at least one of user equipment identity, system frame number, and a (total) number of sub-bands which are in the subset.

[0040] Block 310 concerns the cell-wide signaling noted above; the signaling of block 302 comprises signaling all UEs in the cell which satisfy a particular category, class or capability. Block 312 provides the embodiment in which the signaling of block 302 comprises signaling explicitly how the sub-bands are defined.

[0041 ] Block 314 specifies that the second DCI format comprises a resource allocation field having a length that depends on how many physical resource blocks are in the subset (for example, how many n sub-bands are in the subset and how many P Bs are in those sub-bands).

[0042] The logic flow 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. 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 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] 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 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 which provides connectivity with further networks (e.g., a publicly switched telephone network and/or a data communications network/Internet) .

[0045] The 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 which tangibly stores at least one computer program (PROG) 20C or other set of executable instructions, 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 stored in the MEM 20B at reference number 20G are the rules for how to utilize the new/second DCI format which has the variable length for its resource allocation field, including searching only in the subset of sub-bands where the resources allocated by this new DCI format are restricted to lie as detailed above in the various exemplary embodiments.

[0046] 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 that tangibly stores at least one computer program (PROG) 22C or other set of executable instructions, 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. The eNB 22 stores at block 22G similar rules for how to utilize the new/second DCI format which has the variable length for its resource allocation field.

[0047] 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 and/or a chipset which may or may not be inbuilt onto an RF front end chip within those devices 20, 22 and which also operates utilizing the new DCI format according to these teachings. [0048] 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 above for Figure 3. 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 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). 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.

[0049] 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 telephones, navigation devices, laptop/palmtop/tablet computers, digital cameras and music devices, and Internet appliances, as well as the machine-to-machine type devices mentioned above.

[0050] 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.

[0051 ] 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 and LTE-A system, as noted above the exemplary embodiments of this invention may be used with various other CA-type wireless communication systems.

[0052] 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 IS CLAIMED IS:

1. An apparatus comprising:

at least one processor and at least one memory storing a computer program; in which the at least one memory with the computer program is configured with the at least one processor to cause the apparatus to at least:

signal a user equipment to utilize a second format for downlink control information as opposed to a first format for downlink control information, in which resources allocated by the first format are not restricted respecting a whole bandwidth of a carrier and resources allocated by the second format are restricted to a subset of sub-bands of the bandwidth; and

schedule the user equipment on resources that are restricted to the subset of sub-bands using the second format.

2. The apparatus according to claim 1, in which

the sub-bands are defined for the user equipment specifically or for an entire cell in which the user equipment operates by predetermined static frequency bounds.

3. The apparatus according to claim 1, in which

the sub-bands are defined by a predetermined algorithm which identifies a sub-band index as a function of at least one of user equipment identity, system frame number, and a number of sub-bands which are in the subset.

4. The apparatus according to claim 1, in which signaling the user equipment comprises signaling all user equipments in the cell which satisfy a particular category, class or capability.

5. The apparatus according to claim 1, in which signaling the user equipment comprises signaling explicitly how the sub-bands are defined.

6. The apparatus according to claim 1, in which the second format comprises a resource allocation field having a length that depends on how many physical resource blocks are in the subset.

7. The apparatus according to any of claims 1 through 6, in which the apparatus comprises a network access node.

8. A method comprising:

signaling a user equipment to utilize a second format for downlink control information as opposed to a first format for downlink control information, in which resources allocated by the first format are not restricted respecting a whole bandwidth of a carrier and resources allocated by the second format are restricted to a subset of sub-bands of the bandwidth; and

scheduling the user equipment on resources that are restricted to the subset of sub-bands using the second format.

9. The method according to claim 8, in which

10. The method according to claim 8, in which

11. The method according to claim 8, in which signaling the user equipment comprises signaling all user equipments in the cell which satisfy a particular category, class or capability.

12. The method according to claim 8, in which signaling the user equipment comprises signaling explicitly how the sub-bands are defined.

13. The method according to claim 8, in which the second format comprises a resource allocation field having a length that depends on how many physical resource blocks are in the subset.

14. The method according to any of claims 8 through 13, in which the method is executed by a network access node.

15. A computer readable memory tangibly storing a computer program executable by at least one processor, the computer program comprising:

code for signaling a user equipment to utilize a second format for downlink control information as opposed to a first format for downlink control information, in which resources allocated by the first format are not restricted respecting a whole bandwidth of a carrier and resources allocated by the second format are restricted to a subset of sub-bands of the bandwidth; and

code for scheduling the user equipment on resources that are restricted to the subset of sub-bands using the second format.

16. The computer readable memory according to claim 15, in which the sub-bands are defined for the user equipment specifically or for an entire cell in which the user equipment operates by predetermined static frequency bounds.

17. The computer readable memory according to claim 15, in which

18. The computer readable memory according to claim 15, in which signaling the user equipment comprises signaling all user equipments in the cell which satisfy a particular category, class or capability.

19. The computer readable memory according to claim 15, in which signaling the user equipment comprises signaling explicitly how the sub-bands are defined.

20. The computer readable memory according to claim 15, in which the second format comprises a resource allocation field having a length that depends on how many physical resource blocks are in the subset.