Resource allocation

Abstract

Efficient encoding techniques are described for encoding resource allocation data to be signalled to a user device. In one encoding technique one or more frequency blocks are assigned to a user device and a plurality of resource blocks within the assigned frequency blocks are allocated to the user device. The assignment of frequency blocks and the resource block allocation are encoded separately and signalled to the user device. On receipt of the signalled information the user device interprets the frequency block assignment and uses this when interpreting the resource block allocation.

Description

Where additional control fields are present in the resource assignment message, the r remainder bits may be used in those fields. Alternatively, the remainder bits can be filled with padding bits.

As described previously, the base station 5 is configured to signal the assignment bit masks to the mobile telephone 3, on a physical downlink control channel (PDCCH), as part of a resource allocation field in the scheduling grant. The decoder module 91 of each mobile telephone 3 is configured, in a complementary manner to the encoder module 35 of the base station 5, to decode the resource allocation field to determine in which of the frequency blocks 40 it has been allocated resources. The decoder module 91 then works out N_RB and P and from this the size of the RBG assignment bit mask, which it then uses to determine which resource block groups 46 within the assigned frequency blocks 40 have been allocated to it.

Thus, in this embodiment, the total bit width (or length) of the resource allocation field for distributed resource allocation is fixed thereby allowing a single downlink control information (DCI) format to be used regardless of the number of frequency blocks 40 allocated to the mobile telephone 3.

Virtual Contiguous Resource Block (VCRB) Assignment

FIG. 8 shows an example of resource allocation according to the VCRB assignment method summarised in (3) above. In the example of FIG. 8 a mobile telephone 3 has been assigned to adjacent frequency blocks 40-2 and 40-3 (FB₁ and FB₂) (assigned for example using a frequency block assignment bit mask as described above). Within the assigned frequency blocks a resource block group comprising a virtually contiguous sequence of resource blocks has been allocated to the mobile telephone 3. The virtually contiguous sequence spans the two frequency blocks to which the mobile telephone 3 is assigned.

The encoder module 35 of the base station 5 is configured effectively to concatenate the N_RB assignable resource blocks 42 in the assigned frequency blocks and to treat them as a continuous sequence of resource blocks (numbered from 0 through to N_RB−1), arranged and implicitly numbered in order of increasing frequency. The allocated resource block sequence in FIG. 8 can thus be fully defined by the implicit index number of its start block (RB_START) in the concatenated sequence and its length (RB_LENGTH) in terms of number of resource blocks. Therefore, in this embodiment, the encoder module 35 of the base station 5 is configured to encode the index number of the start block (RB_START) and the length of the allocated sequence (RB_LENGTH) into a single integer ‘k’ as follows:

$\mathrm{if}\left({\mathrm{RB}}_{\mathrm{LENGTH}}-1\right)\le \mathrm{floor}\left(\frac{N_{\mathrm{RB}}}{2}\right)$ $\mathrm{then}k=N_{\mathrm{RB}}\left({\mathrm{RB}}_{\mathrm{LENGTH}}-1\right)+{\mathrm{RB}}_{\mathrm{START}}\mathrm{else}k=N_{\mathrm{RB}}\left(N_{\mathrm{RB}}-\left({\mathrm{RB}}_{\mathrm{LENGTH}}-1\right)\right)+\left(N_{\mathrm{RB}}-1-{\mathrm{RB}}_{\mathrm{START}}\right)$

(floor(x) is the floor function the result of which is the largest integer not greater than x)

The encoded integer ‘k’ can thus be signalled o the mobile telephone 3 using significantly fewer bits than if the allocation were encoded as a bitmap.

Conversely, the decoder module 91 of the mobile telephone 3 is configured to extract the index number of the start block and the length of the allocated sequence based on the following functions:

where:

$a=\mathrm{floor}\left(\frac{k}{N_{\mathrm{RB}}}\right)+1$
and: b=k mod N_RB
if (a+b)>N_RB then RB_LENGTH=N_RB+2−a and RB_START=N_RB−1−b
else: RB_LENGTH=a and RB_START=b

The encoded integer ‘k’ thus contains all the information required for the mobile telephone 3 to determine which resource blocks 42 have been allocated to it.

By way of example, Table 3 illustrates a selection of the typical values of ‘k’, which may be used to encode different values of RB_START and RB_LENGTH where the number of assignable resource blocks 42 N_RB is assumed to be 220.

TABLE 3
Typical ‘k’ values for VCRB assignment (assuming NRB = 220)
	Allocation Size (RBLENGTH)
RBSTART	2	3	4	. . .	20	21	22	. . .	108	109	110	111
0	220	440	660	. . .	4180	4400	4620	. . .	23540	23760	23980	24200
1	221	441	661	. . .	4181	4401	4621	. . .	23541	23761	23981	24201
2	222	442	662	. . .	4182	4402	4622	. . .	23542	23762	23982	24202
3	223	443	663	. . .	4183	4403	4623	. . .	23543	23763	23983	24203
4	224	444	664	. . .	4184	4404	4624	. . .	23544	23764	23984	24204
. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .
50	270	490	710	. . .	4230	4450	4670	. . .	23590	23810	24030	24250
51	271	491	711	. . .	4231	4451	4671	. . .	23591	23811	24031	24251
52	272	492	712	. . .	4232	4452	4672	. . .	23592	23812	24032	24252
53	273	493	713	. . .	4233	4453	4673	. . .	23593	23813	24033	24253
54	274	494	714	. . .	4234	4454	4674	. . .	23594	23814	24034	24254
55	275	495	715	. . .	4235	4455	4675	. . .	23595	23815	24035	24255
56	276	496	716	. . .	4236	4456	4676	. . .	23596	23816	24036	24256
57	277	497	717	. . .	4237	4457	4677	. . .	23597	23817	24037	24257
58	278	498	718	. . .	4238	4458	4678	. . .	23598	23818	24038	24258
59	279	499	719	. . .	4239	4459	4679	. . .	23599	23819	24039	24259
60	280	500	720	. . .	4240	4460	4680	. . .	23600	23820	24040	24260
. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .	. . .
108	328	548	768	. . .	4288	4508	4728	. . .	23648	23868	24088	24308
109	329	549	769	. . .	4289	4509	4729	. . .	23649	23869	24089	24309
110	330	550	770	. . .	4290	4510	4730	. . .	23650	23870	24090	N/A
111	331	551	771	. . .	4291	4511	4731	. . .	23651	23871	N/A	N/A

The number of independent values of the integer k required to encode any contiguous allocated sequence within the concatenated sequence of N_RB assignable resource blocks 42 is equal to N_RB(N_RB+1)/2. Hence, any contiguous allocated sequence within the concatenated sequence may be signalled using log₂(N_RB (N_RB+1)/2) bits without needing a lookup table (although it will be appreciated that this does not preclude use of such a table).

Thus, by using this encoding technique, the theoretical minimum number of bits required for signalling a contiguous resource allocation can be estimated for different bandwidths as follows (where each frequency block is assumed to be 20 MHz):

(a) 13 bits for 20 MHz (1×20 MHz bandwidth) and N_RB˜110RBs

(b) 15 bits for 40 MHz (2×20 MHz bandwidth) and N_RB˜220RBs

(c) 16 bits for 60 MHz (3×20 MHz bandwidth) and N_RB˜330RBs

(d) 17 bits for 80 MHz (4×20 MHz bandwidth) and N_RB˜440RBs

(e) 18 bits for 100 MHz (5×20 MHz bandwidth) for N_RB˜550RBs

However, in order to avoid the need for different DCI formats and to reduce the number of blind decoding attempts, the encoder module 35 is configured to generate a fixed-size resource allocation field for allocations where the allocated resource blocks 42 span two or more frequency blocks 40. When generating the encoded integer the value of N_RB used by the encoder module 35 is the number of assignable resource blocks 42 across all five frequency blocks 40 (˜550). This ensures that all possible virtually contiguous resource block allocations in any combination of adjacent frequency blocks 40 can be encoded using a single value of ‘k’. Thus, in the fixed-length resource allocation field, the 18 bits referred to in (e) above are always used to encode the resource allocation regardless of the actual as signed bandwidth. Signalling using the fixed-length resource allocation field also allows the allocation to be signalled without requiring the assignment of frequency blocks to be signalled separately (for example, in a frequency block allocation bit mask).

It will be appreciated that some resource blocks 42 may be reserved and may not therefore be available for use by the mobile telephone 3 for the PDSCH or PUSCH. For example, in the uplink, resource blocks may be reserved for the physical uplink control channel (PUCCH), and are therefore not available for PUSCH transmission.

In one embodiment this situation is addressed by the encoder module 35 being configured to exclude the resource blocks reserved for the PUCCH channels from the resource block numbering in the concatenated sequence (i.e. PUCCH resource blocks are not counted) and thus N_RB represents only the potential resources available for the PUSCH channel. In such an embodiment, the decoder module 91 is configured, in a complementary manner, to exclude any resource blocks 42 reserved for the PUCCH channels when deriving the allocated resource blocks from the extracted RB_START value and RB_LENGTH.

In another embodiment the resource blocks 42 used for the PUCCH channels are not excluded from the RB numbering, but instead the mobile telephone 3 is configured effectively to ignore any PUCCH resource blocks within the allocation signalled by the base station 5 so that it does not attempt to use them for PUSCH transmissions.

FIG. 9 shows another example of resource allocation which may be signalled using a variation on the VCRB assignment method described with reference to FIG. 8. In the example of FIG. 9 a mobile telephone 3 has been assigned to non-adjacent frequency blocks (in this case FB₁ and FB₃). Within each assigned frequency block a resource block group comprising a contiguous sequence of resource blocks has been allocated to the mobile telephone 3. Each of the two allocated contiguous sequences is of equal length (RB_LENGTH) and the first block in each sequence has the same relative position relative to the first resource block in its respective frequency block (RB_START/RB_START′).

In this embodiment the encoder module 35 of the base station 5 is configured to encode each frequency block allocated to a mobile telephone 3 into a frequency block assignment bit mask, each bit of which represents a different frequency block (as described above with reference to FIG. 7). The encoder module 35 is also configured to encode the relative position (RB_START/RB_START′) and length (RB_LENGTH) of each allocated sequence of resource blocks as a 13 bit encoded integer ‘k’ as described previously for the VCRB assignment method. 13 bits is sufficient for encoding ‘k’ because the size and relative position of the allocated resource blocks in each assigned frequency block is the same and therefore ‘k’ is only required to represent the resource allocation within a single 20 MHz frequency block. The total number of bits required to signal the allocation is therefore 18 (comprising 5. bits for the frequency block assignment mask and 13 bits for the encoded value ‘k’).

The decoder module 91 in the mobile telephone 3 is configured, in a complementary manner to the encoder module 35, to determine the frequency blocks 40 to which it is assigned from the frequency block assignment bit mask, and the size and relative position of the contiguous sequence of allocated resource blocks in each assigned frequency block from the value of ‘k’ as described previously.

FIG. 10 shows yet another example of resource allocation which may be signalled using a variation on the VCRB assignment method described with reference to FIG. 9. Like in FIG. 9, in the example of FIG. 10 a mobile telephone 3 has been assigned to non-adjacent frequency blocks (in this case FB₁ and FB₃). However, in FIG. 10 the allocated resource blocks comprise a contiguous sequence of resource blocks which span the interface between the assigned frequency blocks when they are concatenated. The contiguous sequence thus has a length (RB_LENGTH) which is equal to the total number of allocated blocks across the two frequency blocks. The first block in the sequence has an implicit index number (RB_START) in the lowest frequency assigned frequency block (in this case FB₁).

In this embodiment the encoder module 35 of the base station 5 is configured to encode each frequency block allocated to a mobile telephone 3 into a frequency block assignment bit mask, each bit of which represents a different frequency block (as described above with reference to FIG. 7). The encoder module 35 is also configured to concatenate the assignable resource blocks in the assigned frequency blocks and to encode the position (RB_START) and length (RB_LENGTH) of the allocated sequence of resource blocks as an encoded integer C as described previously. In this case, the number of bits required for encoding ‘k’ will depend on the number of frequency blocks 40 to which the mobile telephone 3 is assigned as described previously.

The decoder module 91 in the mobile telephone 3 is configured, in a complementary manner to the encoder module 35, to determine the frequency blocks 40 to which it is assigned from the frequency block assignment bit mask, and to determine the size and relative position of the contiguous sequence of allocated resource blocks in each assigned frequency block from the value of ‘k’ as described previously.

Modifications and Alternatives

Detailed embodiments have been described above. As those skilled in the art will appreciate, a number of modifications and alternatives can be made to the above embodiments whilst still benefiting from the inventions embodied therein. By way of illustration only a number of these alternatives and modifications will now be described.

In the above embodiment, a mobile telephone 3 based telecommunications system was described. As those skilled in the art will appreciate, the signalling, encoding and decoding techniques described in the present application can be employed in any communications system. In particular, many of these techniques can be used in wire or wireless based communications systems which either use electromagnetic signals or acoustic signals to carry the data. In the general case, the base stations 5 and the mobile telephones 3 can be considered as communications nodes or devices which communicate with each other. Other communications nodes or devices may include user devices such as, for example, personal digital assistants, laptop computers, web browsers, etc.

In the above embodiments, a number of modules were described. As those skilled will appreciate, these modules may be software modules which may be provided in compiled or un-compiled form and may be supplied to the base station 5 or to the mobile telephone 3 as a signal over a computer network, or on a recording medium. Further, the functionality performed by part or all of these modules may be performed using one or more dedicated hardware circuits. However, the use of software modules is preferred as it facilitates the updating of base station 5 and the mobile telephones 3 in order to update their functionalities.

Various other modifications will be apparent to those skilled in the art and will not be described in further detail here.

The following is a detailed description of the way in which the present inventions may be implemented in the currently proposed 3GPP LTE-Advanced standard. Whilst various features are described as being essential or necessary, this may only be the case for the proposed 3GPP standard, for example due to other requirements imposed by the standard. These statements should not, therefore, be construed as limiting the present invention in any way.

Introduction

LTE-Advanced will require L1/L2 control signalling to carry both downlink and uplink resource allocation information corresponding to a number of frequency blocks where each frequency block is backward compatible so that LTE terminals can be scheduled to any one of the frequency blocks. However, LTE-Advanced terminals can be scheduled from one-to-all of the frequency blocks based on their capabilities. Therefore, for LTE-Advanced system with such large bandwidth, the signalling overhead reduction is very demanding, more specifically the resource allocation is the most critical field that needs to be drastically reduced.

In this contribution, we propose three methods of signalling downlink and uplink resource block allocations as follows:

• • Virtual Contiguous Resource Block assignments (VCRBs): A UE can be assigned to contiguous localized RBs that can be physically located on multiple frequency blocks.
  • Virtual Dis-contiguous Resource Block assignments (VDRBs): A UE can be assigned to a multiple of discontinuous RB groups that can be physically located on multiple frequency blocks where each RB group is a certain number of contiguous resource blocks. However, the number of bits scales with the UE capability and its assigned PDSCH/PUSCH transmission bandwidth.
  • Fixed-length Virtual Dis-contiguous Resource Block assignments (FVDRBs): A UE can be assigned to multiple discontinuous RB groups that can be physically located on multiple frequency blocks where each RB group is a certain number of contiguous resource blocks. However, the number of bits are fixed and do not scale with the UE capability and its assigned PDSCH/PUSCH transmission bandwidth.

The DL/UL resource signalling methods that are proposed in this contribution are applicable to both the contiguous and non-contiguous frequency block cases.

Method 1: Virtual Contiguous Resource Block Assignment (VCRBs)

In Rel'8 LTE, a method for contiguous resource block allocation was standardised, for both downlink and uplink resource assignment, by which the UE can be assigned to a number of consecutive resource blocks. The method: called enhanced tree structure where a triangular tree structure is constructed with the number of resource blocks (RBs) available for any bandwidth equal to the number of leaf nodes. The number of nodes of the tree structure equals to N_RB(N_RB+1)/2 and any one of the nodes can be signalled using ceil (log₂(N_RB*(N_RB+1)/2)) bits which represents a starting RB and a number of consecutive RBs. The method is further incorporated with a simple encoding and decoding scheme that do not require a lookup table.

In LTE-Advanced, an improved tree structure method can be applied by introducing the concept of virtual contiguous resource blocks (VCRBs). In some cases, frequency blocks are not physically contiguous, but they can be assumed to be virtually continuous by just concatenating the number of RBs contained in all the configured frequency blocks. The RB numbering starts from bottom-up (from the lowest to the highest frequency block) in the assigned transmission bandwidth.

• • By using the improved tree structure method, the number of bits for different bandwidths can be estimated as follows by assuming each frequency block to be 20 MHz:
    • a) 13 bits for 20 MHz (1×20 MHz bandwidth) and N_RB˜110RBs
    • b) 15 bits for 40 MHz (2×20 MHz bandwidth) and N_RB˜220RBs
    • c) 16 bits for 60 MHz (3×20 MHz bandwidth) and N_RB˜330RBs
    • d) 17 bits for 80 MHz (4×20 MHz bandwidth) and N_RB˜440RBs
    • e) 18 bits for 100 MHz (5×20 MHz bandwidth) for N_RB˜550RBs
  • In the uplink, some RBs will be reserved for PUCCH, and are therefore not available for PUSCH transmission. There are two ways to handle this:
    • a) RBs used for PUCCH channels are excluded in the RB numbering (i.e. PUCCH RBs are not counted) and N_RB represents only the available resources for PUSCH channel.
    • b) RBs used for PUCCH channels are included in the RB numbering, but it is understood that any PUCCH RBs within the allocation signalled by the eNB are not used PUSCH transmission at the UE.

In order to avoid different DCI formats and also reduce the number of blind decoding attempts, it is then desirable have a fixed-size resource allocation field for all allocations of two or more frequency blocks, therefore 18 bits is simply enough for LTE-A system as in e) above.

Method 2: Virtual Dis-Contiguous Resource Block Assignment (VDRBs)

Virtual Dis-contiguous resource blocks (VDRBs) can be introduced by concatenating the RBs contained in all the allocated frequency blocks, and then applying a bit-map allocation method. An example is shown in Table 1.

TABLE 1
VDRBs assignment across multiple frequency blocks
	Number of 20 MHz
	frequency blocks assigned
	for PDSCH/PUSCH
	1	2	3	4	5
Total of assignable RBs, NRB RBG	~110	~220	~330	~440	~550
size, P	4	6	8	10	12
RBG Assignment bit mask	28	37	42	44	46
size = ceil (NRB,/P)
Frequency Block Assignment bit	5	5	5	5	5
mask size
Total size (bits)	33	42	47	49	51

The Frequency Block Assignment bit mask consists of one bit per frequency block and identifies which frequency blocks are allocated to the UE for PDSCH/PUSCH transmission. The number of frequency blocks allocated (i.e. the number of ones in the bit mask) defines the total number of assignable RBs, N_RB, and the RBG size, P. The N_RB RBs in the allocated frequency blocks are numbered from 0 to N_RB−1 from lowest to highest frequency, and grouped into ceil (N_RB/P) RB groups where one RB group consists of P RBs. The RBG Assignment bit mask contains one bit for each RB group, and indicates which RB groups are allocated. An example is shown in the following example.

##STR00001##

In Table 1, the RB group size P increases with the number of frequency blocks. It is assumed that if finer granularity is required then a lower number of frequency blocks (with a corresponding smaller value of P) will be allocated.

Method 3: Fixed-Length Virtual Dis-Contiguous RB Assignment (FVDRBs)

The disadvantage of Method 2 is that the total bit width of the resource allocation field depends on the number of assigned frequency blocks, which implies that a different DCI format is needed for each case. Since the UE does not know how many frequency blocks it will be allocated for PDSCH/PUSCH, it must make a blind decoding attempt for each case. To reduce the number of blind decoding attempts, an alternative is to use a fixed-length resource allocation field (i.e. a single DCI format) for all allocations of two or more frequency blocks. The format of the field depends on the number of allocated frequency blocks. An example is shown in Table 2 below:

TABLE 2
FVDRBs assignment across multiple frequency blocks
	Number of 20 MHz
	frequency blocks
	assigned for PDSCH/PUSCH
	2	3	4	5
Total number of assignable PRBs (NRB)	~220	~330	~440	~550
RBG size (P)	5	8	10	12
RBG Assignment bit mask size, (a =	44	42	44	46
ceil (NRB/P) bits)
Frequency Block Assignment bit mask	5	5	5	5
size (m)
Remainder bits (r)	2	4	2	0
Total size bits (y)	51	51	51	51

It can be seen that regardless of the number of allocated frequency blocks, each LTE-Advanced UE monitors a fixed-length resource allocation field that has a constant number of bits (i.e. 51 bits in the above example).

In general, for any required total size y, the size of each field can be calculated as follows.

$P=\mathrm{ceil}\left(\frac{N_{\mathrm{RB}}}{y-m}\right)$ $a=\mathrm{ceil}\left(\frac{N_{\mathrm{RB}}}{P}\right)$ $r=y-m-a$

If additional control fields are present in the resource assignment message then it may be possible to use the r remainder bits in those fields. Otherwise they can simply be filled with padding bits.

conclusions

In this contribution, we have described three methods for signalling downlink and uplink resource block allocations. Method 1 is very efficient for only contiguous localised resource allocations. Method 3 is very efficient for dis-continuous RB group allocations. Hence, we propose Method 1 and Method 3 to be adopted for LTE-Advanced DL/UL resource.

This application is based upon and claims the benefit of priority from United Kingdom Patent Application No. 0820109.7, filed on Nov. 3, 2008, the disclosure of which is incorporated herein in its entirety by reference.

Claims

1. A method of signalling resource allocation data in a communication system in which a plurality of frequency blocks, each representing a first bandwidth, are aggregated to support a wider bandwidth, wherein each frequency block comprises a plurality of sub-carriers arranged in a sequence of resource blocks, the method comprising:

determining at least two frequency blocks for aggregation to provide a bandwidth for use by a user device;

determining an allocation of resource blocks within the aggregated frequency blocks, for use by said user device;

generating first resource allocation data identifying the at least two frequency blocks for aggregation to provide said bandwidth for the user device;

generating second resource allocation data identifying the determined allocation of resource blocks for the user device; and

signalling said first and second resource allocation data to said user device.

2. A method as claimed in claim 1, wherein said resource blocks are grouped in a sequence of resource block groups,

wherein said sequence of resource block groups comprises at least one allocated resource block group comprising said determined allocation of resource blocks, and

wherein said second resource allocation data is arranged for identifying the at least one allocated resource block group, thereby to identify said determined allocation of resource blocks.

3. A method as claimed in claim 2, wherein said second resource allocation data is arranged for identifying a relative position of the at least one allocated resource block group in said sequence of resource block groups.

4. A method as claimed in claim 2, wherein said second resource allocation data comprises a resource block group assignment bit mask, and

wherein the or each resource block group in said determined at least two frequency blocks is respectively represented by at least one bit of said assignment bit mask.

5. A method as claimed in claim 2, wherein a number of bits in said second resource block allocation data is dependent on a number of frequency blocks assigned for use by said user device.

6. A method as claimed in claim 2, wherein a number of bits in said second resource block allocation data remains the same regardless of a number of frequency blocks assigned for use by said user device.

7. A method as claimed in claim 2, wherein a number of resource blocks in each resource block group is determined in dependence on a number of frequency blocks assigned for use by said user device.

8. A method as claimed in claim 1, wherein said allocation of resource blocks comprises at least one contiguous sequence of resource blocks, and

wherein said second resource allocation data comprises a value which encodes a position of a start resource block of the contiguous sequence and a number of resource blocks in the contiguous sequence.

9. A method as claimed in claim 8, wherein said allocation of resource blocks comprises a contiguous sequence of resource blocks in each frequency block assigned for use by the user device,

wherein each contiguous sequence comprises a same number of resource blocks, and

wherein the start resource block of each contiguous sequence has a same relative position in the frequency block in which it is located.

10. A method as claimed in claim 8, wherein said allocation of resource blocks comprises a contiguous sequence of resource blocks starting in a first frequency block assigned for use by the user device and ending in a second frequency block assigned for use by the user device.

11. A method as claimed in claim 1, wherein said first resource allocation data comprises a frequency block assignment bit mask, and

wherein each frequency block is respectively represented by at least one bit of said frequency block assignment bit mask.

12. A method as claimed in claim 1. wherein said determining the at least two frequency blocks determines that a plurality of said frequency blocks are assigned for use by the user device, and

wherein in said generating second resource allocation data, the sequence of resource blocks in each of the frequency blocks assigned for use by the user device are treated as a concatenated sequence, and said generated resource allocation data is arranged to indicate a position of said allocated resource blocks in said concatenated sequence.

13. A method according to claim 1, wherein said second resource allocation data is dependent on the determined at least two frequency blocks for aggregation.

14. A method according to claim 1, wherein the plurality of frequency blocks are aggregated to support the wider bandwidth of up to 100 MHz.

15. A method, performed by a user device, of determining resource allocation in a communication system in which a plurality of frequency blocks, each representing a first bandwidth, are aggregated to support a wider bandwidth, wherein each frequency block comprises a plurality of sub-carriers arranged in a sequence of resource blocks, the method comprising:

receiving first resource allocation data identifying at least two frequency blocks for aggregation to provide a bandwidth for use by the user device;

receiving second resource allocation data identifying an allocation of resource blocks within the aggregated frequency blocks;

determining the at least two frequency blocks for aggregation to provide said bandwidth using the received first resource allocation data; and

determining the allocation of resource blocks based on the received second resource allocation data and the determined at least two frequency blocks.

16. A method as claimed in claim 15, wherein said resource blocks are grouped in a sequence of resource block groups,

wherein said sequence of resource block groups comprises at least one allocated resource block group comprising said determined allocation of resource blocks, and

wherein said second resource allocation data is arranged for identifying the at least one allocated resource block group, thereby to identify said determined allocation of resource blocks.

17. A method as claimed in claim 16, wherein said second resource allocation data is arranged for identifying a relative position of the at least one allocated resource block group in said sequence of resource block groups.

18. A method as claimed in claim 16, wherein said second resource allocation data is arranged for identifying a relative position of the at least one allocated resource block group in said sequence of resource block groups comprises a resource block group assignment bit mask, and

wherein each resource block group in said determined at least one frequency block is respectively represented by at least one bit of said assignment bit mask.

19. A method as claimed in claim 16, wherein a number of bits in said second resource block allocation data is dependent on a number of frequency blocks assigned for use by said user device.

20. A method as claimed in claim 16, wherein a number of bits in said second resource block allocation data remains the same regardless of a number of frequency blocks assigned for use by said user device.

21. A method as claimed in claim 16, wherein a number of resource blocks in each resource block group is dependent on a number of assigned frequency blocks.

22. A method as claimed in claim 15, wherein said allocation of resource blocks comprises at least one contiguous sequence of resource blocks, and

wherein said second resource allocation data comprises a value which encodes a position of a start resource block of the contiguous sequence and a number of resource blocks in the contiguous sequence.

23. A method as claimed in claim 22, wherein said allocation of resource blocks comprises a contiguous sequence of resource blocks in each assigned frequency block,

wherein each contiguous sequence comprises a same number of resource blocks, and

wherein the start resource block of each contiguous sequence has a same relative position in the frequency block in which it is located.

24. A method as claimed in claim 22, wherein said allocation of resource blocks comprises a contiguous sequence of resource blocks starting in a first assigned frequency block and ending in a second assigned frequency block.

25. A method as claimed in claim 15, wherein said first resource allocation data comprises a frequency block assignment bit mask, and

wherein the or each assigned frequency block is respectively represented by at least one bit of said frequency block assignment bit mask.

26. A method as claimed in claim 15, wherein said at least two frequency blocks comprise a plurality of said frequency blocks, and

wherein, during said determining the allocation of resource blocks, the sequence of resource blocks in each of the assigned frequency blocks are treated as a concatenated sequence, and said resource allocation data is interpreted as indicating the position of said allocated resource blocks in said concatenated sequence.

27. A communication node which is operable to communicate with a plurality of user devices in a communication system in which a plurality of frequency blocks, each representing a first bandwidth, are aggregated to support a wider bandwidth, wherein each frequency block comprises a plurality of sub-carriers arranged in a sequence of resource blocks, the communication node comprising:

means for determining at least two frequency blocks for aggregation to provide a bandwidth for use by a user device;

means for determining an allocation of resource blocks within the aggregated frequency blocks, for use by said user device;

means for generating first resource allocation data identifying the at least two frequency blocks for aggregation to provide said bandwidth for the user device;

means for generating second resource allocation data identifying the determined allocation of resource blocks for the user device; and

means for signalling said first and second resource allocation data to said user device.

28. A user device which is operable to communicate with a communication node in a communication system in which a plurality of frequency blocks, each representing a first bandwidth, are aggregated to support a wider bandwidth, wherein each frequency block comprises a plurality of sub-carriers arranged in a sequence of resource blocks, the user device comprising:

means for receiving first resource allocation data identifying at least two frequency blocks for aggregation to provide a bandwidth for use by the user device;

means for receiving second resource allocation data identifying an allocation of resource blocks within the aggregated frequency blocks;

means for determining the at least two frequency blocks for aggregation to provide said bandwidth using the received first allocation data; and

means for determining the allocation of resource blocks based on the received second resource allocation data and the determined at least two frequency blocks.

29. A communication node which communicates with a plurality of user devices in a communication system in which a plurality of frequency blocks, each representing a first bandwidth, are aggregated to support a wider bandwidth, wherein each frequency block comprises a plurality of sub-carriers arranged in a sequence of resource blocks, the communication node comprising:

a processor and a transceiver circuit, wherein the processor is configured to:

a determiner that determines determine at least two frequency blocks for aggregation to provide a bandwidth for use by a user device;

a determiner that determines determine an allocation of resource blocks within the aggregated frequency blocks, for use by said user device;

a generator that generates generate first resource allocation data identifying the at least two frequency blocks for aggregation to provide said bandwidth for the user device;

a generator that generates generate second resource allocation data identifying the determined allocation of resource blocks for the user device; and

a signaller that signals control the transceiver circuit to signal said first and second resource allocation data to said user device.

30. A user device which communicates with a communication node in a communication system in which a plurality of frequency blocks, each representing a first bandwidth, are aggregated to support a wider bandwidth, wherein each frequency block comprises a plurality of sub-carriers arranged in a sequence of resource blocks, the user device comprising:

a processor and a transceiver circuit, wherein the processor is configured to:

a receiver that receives control the transceiver circuit to receive first resource allocation data identifying at least two frequency blocks for aggregation to provide a bandwidth for use by the user device;

a receiver that receives control the transceiver circuit to receive second resource allocation data identifying an allocation of resource blocks within the aggregated frequency blocks;

a determiner that determines determine the at least two frequency blocks for aggregation to provide said bandwidth using the received first resource allocation data; and

a determiner that determines determine the allocation of resource blocks based on the received second resource allocation data and the determined at least two assigned frequency blocks; and

communicate with the communication node using the allocation of resource blocks.

31. A non-transitory computer-readable storage medium encoded with a computer program encoded with instructions for causing a computer to perform a method of signalling resource allocation data in a communication system in which a plurality of frequency blocks, each representing a first bandwidth are aggregated to support a wider bandwidth, wherein each frequency block comprises a plurality of sub-carriers arranged in a sequence of resource blocks, the method comprising:

determining at least two frequency blocks for aggregation to provide a bandwidth for use by a user device;

determining an allocation of resource blocks within the at least two aggregated frequency blocks, for use by said user device;

generating first resource allocation data identifying the at least two frequency blocks for aggregation to provide said bandwidth for the user device;

generating second resource allocation data identifying the determined allocation of resource blocks for the user device; and

signalling said first and second resource allocation data to said user device.

32. A user device which communicates with a communication node in a communication system in which a plurality of frequency blocks, each representing a first bandwidth, are aggregated to support a wider bandwidth, the user device comprising: a processor and a transceiver circuit, wherein the processor is configured to:

control the transceiver circuit to receive first resource allocation data identifying at least two frequency blocks for aggregation to provide a bandwidth for use by the user device:

control the transceiver circuit to receive second resource allocation data identifying an allocation of resource blocks within the aggregated frequency blocks:

determine the at least two frequency blocks for aggregation to provide the bandwidth using the received first resource allocation data: and

determine the allocation of resource blocks based on the received second resource allocation data and the determined at least two frequency blocks; and

control the transceiver circuit to communicate with the communication node using the allocation of resource blocks.

33. A communication node which communicates with a plurality of user devices in a communication system in which a plurality of frequency blocks, each representing a first bandwidth, are aggregated to support a wider bandwidth, the communication node comprising:

a processor and a transceiver circuit, wherein the processor is configured to:

determine at least two frequency blocks for aggregation to provide a bandwidth for use by a user device;

determine an allocation of resource blocks within the aggregated frequency blocks, for use by said user device;

generate first resource allocation data identifying the at least two frequency blocks for aggregation to provide said bandwidth for the user device;

generate second resource allocation data identifying the determined allocation of resource blocks for the user device; and

control the transceiver circuit to signal said first and second resource allocation data to said user device.

34. A user device configured to communicate with a communication node via at least two frequency blocks which are aggregated to support a wider transmission bandwidth, the user device comprising:

a processor and a transceiver circuit, wherein the processor is configured to:

control the transceiver circuit to receive first resource allocation data and second resource allocation data, wherein the second resource allocation data is different from the first resource allocation data: and

determine the at least two frequency blocks based on the received first allocation data,

wherein the second resource allocation data identifies at least one physical downlink shared channel (PDSCH) within the at least two frequency blocks,

wherein the processor is further configured to decode the at least one PDSCH based on the second resource allocation data; and

control the transceiver circuit to communicate with the communication node using the at least one PDSCH.

35. A communication node configured to communicate with a user device via at least two frequency blocks which are aggregated to support a wider transmission bandwidth, the communication node comprising:

a processor and a transceiver circuit, wherein the processor is configured to:

generate first resource allocation data identifying the at least two frequency blocks for aggregation;

generate second resource allocation data identifying an allocation of resource blocks within the aggregated frequency blocks; and

control the transceiver circuit to signal said first and second resource allocation data to said user device.