The invention will now be described based on an embodiment with reference to the accompanying drawings in which:
In the following, an embodiment of the invention will be described based on a channel-dependent scheduling and link adaptation (rate and/or power control) in time and frequency domain, where a scheduler function or unit assigns a number of resource blocks, e.g., frequency resource blocks, to a user.
An efficient method of signalling the above scheduling information is provided as an optimum solution for any number of user allocations. The essence of the new signalling approach is to compress the user signal space such that the total required number of signalling bits will become ceil(M*log 2(N+1)). Compared to the initially discussed signalling approach which provides a total required signalling bit number of M*ceil(log 2(N+1)) as the signalling need, signalling savings can be achieved by moving the “ceil” function field, e.g., in the case of 24 available frequency resource blocks (M=24) and 4 allocated users (N=4), 22% in signalling overhead can be saved. In the case of 12 available frequency resource blocks (M=12) and 8 allocated users (N=8), 19% in signalling overhead can be saved.
The exemplary embodiment starts from the fact that the EEI and RTI fields of
In one embodiment, the compressing or encoding of the scheduling decisions or information is based on the following general equation:
wherein T denotes the compressed scheduling information or total state to be signalled to the scheduled devices (users), Sk denotes the resource allocation state which is selected from the values 0, 1, . . . , N−1, R denotes the number of possible resource allocation states, M denotes the available number of resource blocks (frequency resource blocks), and k denotes the sequential number of the resource block, starting from index ‘0’.
Applied to the specific example of the fixed part 101 of the allocation information table of
In the case of M=24, only 39 bits are required for signalling the EEI and RTI bits, compared to 48 bits of the conventional allocation table at a system bandwidth of 10 MHz. In the case of M=48, only 77 bits are required for signalling the EEI and RTI bits, compared to 96 bits of the conventional allocation table at a system bandwidth of 20 MHz.
The resource allocation states can be defined and set, such that the following state values are valid (the naming and order of the states is not important to the principle):
Following equation (1), the allocation state for resource block ‘k’ can be obtained as follows:
S
k
=x
k·3k, (2)
where xk can take the values {0,1,2} depending on the state of the kth resource block.
Referring again to equation (1), the total state T can be defined as the sum of the allocation states (and decoded correspondingly). I.e., the transmitted scheduling information of the EEI and RTI bits of the fixed part 101 of
T=sum(Sk) (3)
over the values of the sequential number ‘k’ of the resource block, where k=24 for a system bandwidth of 10 MHz, and k=48 for a system bandwidth of 20 MHz.
Similarly, it is possible to define a decoding algorithm, which will decode the state information. However, as there is a tradition of specifying the encoding of data rather than the decoding, the above algorithm should be sufficient for the skilled person to derive the encoding algorithm.
By transmitting the compressed scheduling information 103 instead of the original fixed part 101, a significant reduction of signalling bits can be achieved.
In summary, a method, terminal device, network element, and computer program product for signalling a scheduling information used for indicating resource allocation states of a plurality of available resource blocks to a plurality of scheduled devices have been described, wherein a resource allocation state is set for each of the available resource blocks and multiplied by the number of possible allocation states to the power of a sequential number of the resource block. Then, the multiplication results of all available resource blocks are summed and the summing result is transmitted to the plurality of scheduled devices. Thereby, the required amount of signalling bits can be reduced considerably, while still maintaining the same signalling information content.
The above processing steps described above and performed by the encoder 200 of the access device 20 of
It is apparent that the invention can easily be extended to the multi-layer domain, since it relates to the content of the fixed length part. In the multi-layer domain, the layer may represent the spatial dimension. For example, in a transmission using multiple antennas, the time-frequency resource defined by the frequency resource block may be re-used by spatial multiplexing.
The described embodiments are related to signalling of frequency domain packet scheduling decisions. However, the invention, according to various embodiments, can be applied whenever efficient signalling for any kind of scheduling information is needed. Exemplary embodiments may thus vary within the scope of the attached claims.
Number | Date | Country | Kind |
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EP 06 009 473.7 | May 2006 | EP | regional |