METHOD AND TRANSMITTER FOR RESOURCE ALLOCATION IN CARRIER

Abstract

The invention relates to allocating resources in a carrier when several subcarrier spacing configurations coexists, and more particularly to avoid or at least reduce the loss of resources when allocating in such a carrier. The invention proposes to align contiguous resource blocks (RB.sub.1) of a subcarrier spacing configuration (f.sub.1) on a raster of a different subcarrier spacing configuration (f.sub.0). Therefore the invention proposes a method to allocate such resource blocks to a terminal.

Claims

1. A method implemented by computer for a resource allocation in a carrier comprising several subcarriers, whereby said resource allocation is for allocating at least one resource of said carrier to at least one terminal, said method comprising: a) defining for said carrier at least a first f.sub.j and a second f.sub.i different subcarrier spacing configurations, one of said subcarrier spacing configurations being a multiple of the other of said subcarrier spacing configurations, and defining the difference .sub.ij between the lowest frequency among the subcarriers that are allowable for subcarrier spacing f.sub.j and the lowest frequency among the subcarriers that are allowable for subcarrier spacing f.sub.i, b) defining in said carrier at least one resource block RB.sub.j comprising N subcarriers of said first subcarrier spacing configuration f.sub.j, said RB.sub.j having the subcarrier with the lowest frequency among said several subcarriers of the carrier that are allowable for subcarrier spacing f.sub.j, and allocating in said carrier at least a number L.sub.i of resource blocks comprising N subcarriers of said second subcarrier spacing configuration f.sub.i to a given terminal, wherein the allocation comprises: determining the frequency f.sub.jm of the subcarrier having the lowest frequency that is allowable for subcarrier spacing f.sub.j among the subcarriers of RB.sub.j, and determining a frequency f.sub.im-start of the subcarrier having the lowest frequency among the subcarriers of said L.sub.i resource blocks allocated to the same terminal, said frequency f.sub.im-start satisfying to f.sub.im-start=f.sub.jm+(kN)*f.sub.j+.sub.ij, with k a positive integer, and determining a frequency f.sub.im-end of the subcarrier having the highest frequency among the subcarriers of said L.sub.i resource blocks allocated to the same terminal, said frequency f.sub.im-end satisfying to f.sub.im-end=f.sub.im-start+(L.sub.iN1)*f.sub.i.

2. The method according to claim 1, wherein said number L.sub.i, satisfies to:
q.sub.iL.sub.i+NRB.sub.start.sup.(j)N.sub.RB.sup.(j) where: N.sub.RB.sup.(j) is a maximum number of resource blocks comprising N subcarriers of said first subcarrier spacing configuration f that are allowable in said carrier during a time period of a resource block comprising N subcarriers of said first subcarrier spacing configuration f.sub.j, NRB.sub.start.sup.(j) is a maximum number of resource blocks comprising N subcarriers of said first subcarrier spacing configuration f.sub.j having a subcarrier with a lower frequency than said frequency f.sub.im-start that are allowable in said carrier during a time period of a resource block comprising N subcarriers of said first subcarrier spacing configuration f.sub.j, q.sub.i is defined by f.sub.i=q.sub.if.sub.j, where q.sub.i or 1/q.sub.i is an integer.

3. The method according to claim 2, wherein the allocation of resource blocks allocated to the same terminal and comprising N subcarriers of the same subcarrier spacing configuration f.sub.i is defined by a resource indication value RIV, and wherein said RIV value is an integer and is a function of L.sub.i and NRB.sub.start.sup.(j).

4. The method according to claim 3, wherein said RIV function is an injective function of any couple comprising L.sub.i and NRB.sub.start.sup.(j) values.

5. The method according to one of claim 3 or 4, wherein said RIV is a surjective function among the integers from 0 to a maximum value taken by RIV.

6. The method according to claim 3, wherein said f.sub.i being a multiple q.sub.i of said f.sub.j.

7. The method according to claim 6, wherein said relative integer k is not a multiple of q.sub.i.

8. The method according to claim 3, wherein said RIV is defined by: $\{\begin{array}{cc}\mathrm{RIV}=\left(L_i-1\right)+p_i*{\mathrm{NRB}}_{\mathrm{start}}^{\left(j\right)}& \mathrm{if}.Math..Math.{\mathrm{NRB}}_{\mathrm{start}}^{\left(j\right)}{r}_i+1+.Math.\frac{1}{2}*q_i*\left(p_i-1\right).Math.\\ \mathrm{RIV}=p_i*\left(r_i+1+N_{\mathrm{RB}}^{\left(j\right)}-q_i-{\mathrm{NRB}}_{\mathrm{start}}^{\left(j\right)}\right)+p_i-L_i& \mathrm{otherwise}\end{array}$ Where: r.sub.i is a remainder of the division of N.sub.RB.sup.(j) by q.sub.i $p_i=.Math.\frac{N_{\mathrm{RB}}^{\left(j\right)}}{q_i}.Math.$

9. The method according to claim 3, wherein said RIV is defined by: $\{\begin{array}{c}\mathrm{RIV}=\left(L_i-1\right).Math.\left(r_i+1+.Math.\left(p_i-1\right)*\frac{q_i}{2}.Math.+1\right)+{\mathrm{NRB}}_{\mathrm{start}}^{\left(j\right)}\\ \mathrm{if}.Math..Math.{\mathrm{NRB}}_{\mathrm{start}}^{\left(j\right)}{r}_i+1+.Math.\left(p_i-1\right)*\frac{q_i}{2}.Math.\\ \mathrm{RIV}=\left(p_i-L_i\right)*\left(r_i+1+.Math.\left(p_i-1\right)*\frac{q_i}{2}.Math.+1\right)\\ +\left(r_i+1+N_{\mathrm{RB}}^{\left(j\right)}-q_i-{\mathrm{NRB}}_{\mathrm{start}}^{\left(j\right)}\right).Math..Math.\mathrm{otherwise}\end{array}$ Where: r.sub.i is a remainder of the division of N.sub.RB.sup.(j) by q.sub.i $p_i=.Math.\frac{N_{\mathrm{RB}}^{\left(j\right)}}{q_i}.Math.$

10. The method according to claim 3, wherein said RIV is defined by: $\{\begin{array}{c}\mathrm{RIV}=\left(L_i-1\right).Math.\left(N_{\mathrm{RB}}^{\left(j\right)}-q_i+r_i+2\right)+{\mathrm{NRB}}_{\mathrm{start}}^{\left(j\right)}.Math..Math.\mathrm{if}.Math..Math.L_i.Math.p_i.Math.\text{/}.Math.2.Math.\\ \mathrm{RIV}=\left(p_i-L_i\right)*\left(N_{\mathrm{RB}}^{\left(j\right)}-q_i+r_i+2\right)\\ +\left(N_{\mathrm{RB}}^{\left(j\right)}-q_i+r_i+1-{\mathrm{NRB}}_{\mathrm{start}}^{\left(j\right)}\right).Math..Math.\mathrm{otherwise}\end{array}$ Where: r.sub.i is a remainder of the division of N.sub.RB.sup.(j) by q.sub.i $p_i=.Math.\frac{N_{\mathrm{RB}}^{\left(j\right)}}{q_i}.Math.$

11. The method according to claim 3, wherein said RIV is defined by: $\mathrm{RIV}=\left(\underset{l=1}{\overset{L-1}{.Math.}}.Math..Math.S_l^{\left(j\right)}\right)+{\mathrm{NRB}}_{\mathrm{start}}^{\left(j\right)}=\left(L_i-1\right)*\left(N_{\mathrm{RB}}^{\left(j\right)}+1\right)-\frac{q_i*L_i*\left(L_i-1\right)}{2}+{\mathrm{NRB}}_{\mathrm{start}}^{\left(j\right)}$ Where:
S.sub.l.sup.(j)=N.sub.RB.sup.(j)q.sub.i*l+1

12. A transmitter comprising a processor for resource allocation in a carrier comprising several subcarriers, whereby said resource allocation is for allocating at least one resource of said carrier to at least one terminal, said transmitter being configured to perform: a) defining for said carrier at least a first f.sub.j and a second f.sub.i different subcarrier spacing configurations, one of said subcarrier spacing configurations being a multiple of the other of said subcarrier spacing configurations, and defining the difference .sub.ij between the lowest frequency among the subcarriers that are allowable for subcarrier spacing f.sub.j and the lowest frequency among the subcarriers that are allowable for subcarrier spacing f.sub.i, b) defining in said carrier at least one resource block RB.sub.j comprising N subcarriers of said first subcarrier spacing configuration f.sub.j, said RB.sub.j having the subcarrier with the lowest frequency among said several subcarriers of the carrier that are allowable for subcarrier spacing f.sub.j, and allocating in said carrier at least a number L.sub.i of resource blocks comprising N subcarriers of said second subcarrier spacing configuration f.sub.i to a given terminal, wherein, for the allocating of said resource blocks to the given terminal, the transmitter is further configured for: determining the frequency f.sub.jm of the subcarrier having the lowest frequency that is allowable for subcarrier spacing f.sub.j among the subcarriers of RB.sub.j, and determining a frequency f.sub.im-start of the subcarrier having the lowest frequency among the subcarriers of said L.sub.i resource blocks allocated to the same terminal, said frequency f.sub.im-start satisfying to f.sub.im-start=f.sub.jm+(kN)*f.sub.j+.sub.ij, with k a positive integer, and determining a frequency f.sub.im-end of the subcarrier having the highest frequency among the subcarriers of said L.sub.i resource blocks allocated to the same terminal, said frequency f.sub.im-end satisfying to f.sub.im-end=f.sub.im-start+(L.sub.iN1)f.sub.i.

13. A transmitter according to claim 12, comprising a memory unit storing, for each couple of possible values of a number NRB.sub.start.sup.(j) and said L.sub.i a unique resource indication value RIV, NRB.sub.start.sup.(j) being a maximum number of resource blocks comprising N subcarriers of the first subcarrier spacing configuration f.sub.j, having a subcarrier with a lower frequency than said frequency f.sub.im-start that are allowable in said carrier during a time period of a resource block comprising N subcarriers of said first subcarrier spacing configuration f.sub.j, and wherein said transmitter is further configured to: provide the RIV when the allocation of resource blocks to the same terminal defined by the couple of L.sub.i and NRB.sub.start.sup.(j) is performed, and transmit the RIV to said given terminal.

14. A terminal comprising a processor to use a carrier according to a resource allocation being performed in said carrier, said resource allocation having been carried out according to claim 1, said terminal, being configured to use at least a number L.sub.i of resource blocks comprising N subcarriers of said second subcarrier spacing configuration f.sub.i, comprises: a communication module configured to receive an allocation resource block information through a control channel, indicating an allocation of at least a number L.sub.i of resource blocks allocated to the terminal and comprising N subcarriers of said second subcarrier spacing configuration f.sub.i, a processing module which is configured to determine the resource blocks that are allocated to said terminal according to the allocation resource block information, wherein the processing module is configured to determine said resource block allocated to the terminal: as having the frequency f.sub.im-start of the subcarrier having the lowest frequency among the subcarriers of said L.sub.i resource blocks allocated to the same terminal, said frequency f.sub.im-start satisfying to f.sub.im-start=f.sub.jm+(kN)*f.sub.j+.sub.ij, with k a positive integer, and as having the frequency f.sub.im-end of the subcarrier having the highest frequency among the subcarriers of said L.sub.i resource blocks allocated to the same terminal, said frequency f.sub.im-end satisfying to f.sub.im-end=f.sub.im-start+(L.sub.iN1)*f.sub.i.

15. A terminal according to claim 14, wherein said terminal further comprises a memory unit storing for each couple of possible values of a number NRB.sub.start.sup.(j) and said a unique resource indication value RIV, NRB.sub.start.sup.(j) being a maximum number of resource blocks comprising N subcarriers of the first subcarrier spacing configuration f.sub.j having a subcarrier with a lower frequency than said frequency f.sub.im-start that are allowable in said carrier during a time period of a resource block comprising N subcarriers of said first subcarrier spacing configuration f.sub.j, and wherein said processing module is configured to read said memory unit and determine the couple values L.sub.i and NRB.sub.start.sup.(j), upon reception of an RIV value in said allocation resource block information.

16. Computer program product comprising code instructions to perform the method according to claim 1, when said instructions are run by a processor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0096] FIG. 1 illustrates a transmitter and a terminal to which resources are allocated.

[0097] FIG. 2A schematizes a usual resource block scheduling in a carrier where only one numerology is defined.

[0098] FIG. 2B schematizes a usual resource block scheduling in a carrier where several subcarrier spacing configurations coexists usually.

[0099] FIG. 2C schematizes resource block scheduling according to the invention in a carrier where several subcarrier spacing configurations coexists.

[0100] FIG. 3A illustrates a flowchart representing the steps to transmit allocation resource block information.

[0101] FIG. 3B illustrates a flowchart representing the steps of receiving by the terminal the allocation resource block information and decoding this information to define the resource blocks allocated to the terminal.

DESCRIPTION OF EMBODIMENTS

[0102] Referring to FIG. 1, there is shown a transmitter 1, for example in the OFDM-based 5G system like NR, a base station BS and a terminal in the cell of the transmitter. The terminal 2, for example in the OFDM-based 5G system like NR a user equipment UE, is allocated resources by the base station.

[0103] The transmitter 1 comprises one communication module (COM_trans) 3, one processing module (PROC_trans) 4 and a memory unit (MEMO_trans) 5. The MEMO_trans 5 comprises a non-volatile unit which retrieves the computer program and a volatile unit which retrieves the allocation parameters. The PROC_trans which is configured to determine the allocation resource block information, such as a RIV value, according to the resource blocks that are allocated to the terminal. The COM_trans is configured to transmit to the terminal the resource block information.

[0104] The terminal comprises one communication module (COM_term) 6, one processing module (PROC_term) 7 and a memory unit (MEMO_term) 8. The MEMO_term 8 comprises a non-volatile unit which retrieves the computer program and a volatile unit which retrieves the parameters of the carrier and the allocation resource block information. The PROC_term 7 which is configured to determine the resource blocks that are allocated to said terminal according to the allocation resource block information. The COM_term 6 is configured to receive from the transmitter an allocation resource block information.

[0105] In the following, only part of the carrier band or part of a pre-defined portion of the carrier band is represented.

[0106] Referring to FIG. 2A, there is shown part of a carrier where only one numerology is defined and where resource blocks from this numerology are scheduled. For example in LTE/LTE-Advanced a carrier has generally a bandwidth which is a multiple of 20 MHz. Around 90% of this bandwidth is effectively used for the communication needs. In the frequency domain, groups of subcarriers are allocated to a terminal in the resource allocation process. In the LTE/LTE-Advanced subcarriers are grouped into resource blocks (RB) of 12 subcarriers each. The resource block defines the resource allocation granularity, in the sense where a user is allocated a certain number of resource blocks, and therefore a certain bandwidth. In the LTE/LTE-Advanced the subcarrier spacing, that is the frequency spacing between two adjacent subcarrier, is fixed to 15 kHz. Therefore the frequency bandwidth of a resource block is fixed and the possible number of resource blocks in a carrier is only dependent on the carrier bandwidth.

[0107] To a numerology and more specifically to a subcarrier spacing configuration and to a TTI configuration/number of OFDM symbols corresponds a raster, in which the socket of the raster corresponds to the size of a resource block of the same numerology in the frequency domain. All the resource blocks are scheduled aligned on this raster. Each potential resource block nested on the raster is indexed to an integer number. For example in the logical region virtual resource blocks are numbered to 1 to M, M being the maximum number of resource blocks that are allowable in the carrier. The virtual resource block number 1 is the first resource block in the logical region and the M.sup.th resource block is the last resource block of the carrier. Several scheme of allocation exist, for example in LTE/LTE-A resource allocation type 2 is a compact format indicating to a terminal a set of contiguously virtual resource blocks which is allocated to it for downlink or uplink transfer. Therefore a resource indication value (RIV) corresponding to the first resource block RB.sub.start allocated to the terminal and a length L in terms of virtually contiguously allocated resource blocks, is sent to the terminal. The RIV may be defined by:

RIV=M(L1)+NRB.sub.start if (L1)N/2

RIV=M(ML+1)+(M1NRB.sub.start) otherwise

where NRB.sub.start is the number corresponding to the position of RB.sub.start.

[0108] The RIV value enables the terminal to decode the position of the first virtual resource block RB.sub.start which is allocated to it and the number of virtually contiguous resource blocks that are allocated to the terminal. Once RB.sub.start and L are decoded the terminal is able to define the resource blocks that where allocated to it.

[0109] Referring to FIG. 2B, there is shown part of a carrier where several subcarrier spacing configurations coexists and where resource blocks from two of these different numerologies are scheduled. This is notably possible in a OFDM-based 5G system like NR (New Radio) standard. For example in the FIG. 2B, three subcarrier spacing configurations coexists which are f.sub.0, f.sub.1 and f.sub.2. BW is the effectively occupied bandwidth of the carrier. The maximum number of resource blocks of a specific numerology that are allowable in the carrier is

[00019]$N_{\mathrm{RB}}^{\left(i\right)}=.Math.\frac{\mathrm{BW}}{f_i}.Math..$

It should be noted that for certain values of f.sub.i, one extra RB can exist if fractional RBs containing less than N subcarriers are allowed for example at band edge. For the numerical example {f.sub.0, f.sub.1, f.sub.2}={15 kHz, 30 kHz, 120 kHz} and with 12 carrier per resource block. The boxes represent resource blocks containing 12 subcarriers in the frequency domain across a fixed number of OFDM symbols in the time domain (e.g. 7 OFDM symbols). In the time domain, the duration of the scheduling unit is thus different in different numerologies T0>T1>T2 (in the example, T.sub.2=T.sub.1/2=T.sub.0/4 when f.sub.2=2f.sub.1=4f.sub.0). Ti/Tj=f.sub.j/f.sub.i for different numerologies. FIG. 2B shows two resource blocks with different subcarrier spacing configurations scheduled. The top resource block RB.sub.0 has a subcarrier spacing configuration of f.sub.0 and duration of T.sub.0, and under it one resource block RB.sub.1 with a subcarrier spacing configuration of f.sub.1 and duration of T.sub.1. In this example we will assume that RB.sub.0 is the first virtual resource block in the logical band. Each of these resource blocks are nested on its own raster, so in this case RB.sub.1 cannot be contiguous to RB.sub.0. Therefore there is an imposed gap in order to be able to align RB.sub.1 on its raster, leading to loss of resources in the carrier. In the example in FIG. 2B we considered

.sub.ij=0,i,j{0,1,2}.

[0110] Referring to FIG. 2C, as in the example of FIG. 2B there is shown part of a carrier where several subcarrier spacing configurations coexists and where resource blocks from two of these different numerologies are scheduled. More specifically, three subcarrier spacing configurations coexists which are f.sub.0, f.sub.1 and f.sub.2 with f.sub.2=2f.sub.1=4f.sub.0. As in FIG. 2B, two resource blocks with different subcarrier spacing configurations are scheduled in the carrier. In contrary to FIG. 2B, RB.sub.1 is not nested on its raster indeed according to the invention, RB.sub.1 is aligned on a different raster, in this case the raster of RB.sub.0. Since the raster of RB.sub.0 is finer than the one of RB.sub.1, RB.sub.1 can be more freely placed and thus avoid the gap between RB.sub.0 and RB.sub.1.

[0111] Therefore the transmitter allocates to a terminal a set of L contiguous resource blocks, the first resource block allocated being RB.sub.start.sup.(1). Therefore a specific RIV is defined corresponding to the allocation of L contiguous resource blocks of subcarrier spacing configuration f.sub.1 starting on the raster of the subcarrier spacing configuration f.sub.0 allocated by the transmitter to the terminal.

[0112] For example

[00020]$\{\begin{array}{cc}\mathrm{RIV}=\left(L-1\right)+p_1*{\mathrm{NRB}}_{\mathrm{start}}^{\left(0\right)}& \mathrm{if}.Math..Math.{\mathrm{NRB}}_{\mathrm{start}}^{\left(0\right)}{r}_1+1+.Math.p_1-1.Math.\\ \mathrm{RIV}=.Math.\frac{N_{\mathrm{RB}}^{\left(0\right)}}{2}.Math.*\left(r_1+N_{\mathrm{RB}}^{\left(0\right)}-1-{\mathrm{NRB}}_{\mathrm{start}}^{\left(0\right)}\right)+p_1-L& \mathrm{otherwise}\end{array}$

[0113] Where r.sub.1 is the remainder of the division of N.sub.RB.sup.(0) by 2 and NRB.sub.start.sup.(0) is the number corresponding to the position of RB.sub.start.sup.(1).

[0114] Referring to FIG. 3A there is shown a flowchart representing the steps according to an aspect of the invention, to allocate resource blocks in the carrier by the transmitter to a terminal.

[0115] At step 11 (S11) the transmitter sends to the terminal parameters concerning the cell settings including the carrier bandwidth BW and information on supported numerologies and/or raster alignment if needed (e.g. .sub.ij). More specifically the transmitter sends to the terminal information allowing the terminal to know directly or deduce at least the following parameters: f.sub.0, f.sub.1, N.sub.RB.sup.(0).

[0116] At step 12 (S12) the transmitter sends to the terminal the allocation parameters, for example indications allowing the terminal to deduce which type of resource blocks (subcarrier spacing configuration of the resource blocks) will be allocated to the terminal and therefore which set of formulae or lookup table will be necessary to decode the RIV value, if several sets are possible.

[0117] At step 13 (S13) the transmitter defines the contiguous resource blocks it allocates to the terminal.

[0118] At step 14 (S14) the transmitter sends the RIV value through a control channel The RIV value is calculated with the RIV formula mentioned above based on the contiguous resource blocks the transmitter allocates to the terminal.

[0119] Referring to FIG. 3B there is shown a flowchart representing the steps according to an aspect of the invention, to define by the terminal the resource blocks that are allocated to it.

[0120] At step 21 (S21) the terminal receives from the transmitter the parameters concerning the cell settings including the carrier bandwidth BW and information on supported numerologies and/or raster alignment if needed (e.g. .sub.ij). More specifically the terminal receives from the transmitter information allowing the terminal to know directly or deduce at least the following parameters: f.sub.0, f.sub.1, N.sub.RB.sup.(0).

[0121] At step 22 (S22) the terminal receives from the transmitter the allocation parameters, for example indications allowing the terminal to deduce which type of resource blocks (subcarrier spacing configuration of the resource blocks) will be allocated to it and therefore which set of formula or lookup table will be necessary to decode the RIV value, if several sets are possible.

[0122] At step 23 (S23) the terminal receives from the transmitter through a control channel, the RIV value corresponding to the resource blocks allocated to the terminal.

[0123] At step 24 (S24) based on: [0124] the knowledge of N.sub.RB.sup.(0) and q.sub.1=2, the terminal computes: [0125] r.sub.1 the remainder of the division of N.sub.RB.sup.(0) by 2; and

[00021]$.Math..Math.p_1=.Math.\frac{N_{\mathrm{RB}}^{\left(0\right)}}{2}.Math.;$

and [0126] the reception of its RIV value the terminal computes:

[00022]$.Math..Math.P=.Math.\frac{\mathrm{RIV}}{p_1}.Math.;\mathrm{and}$$.Math..Math.R=\mathrm{rem}.Math..Math.\left(\mathrm{RIV},p_1\right);\mathrm{and}$$.Math..Math.{\mathrm{NRB}}_{\mathrm{start}}^{\left(0\right)}=\{\begin{array}{cc}P& \mathrm{if}.Math..Math.P+2.Math.\left(R+1\right)N_{\mathrm{RB}}^{\left(0\right)}\\ N_{\mathrm{RB}}^{\left(0\right)}-1+r_1-P& \mathrm{otherwise}\end{array}.Math..Math..Math..Math.L=\{\begin{array}{cc}R+1& \mathrm{if}.Math..Math.P+q_i*\left(R+1\right)N_{\mathrm{RB}}^{\left(0\right)}\\ p_1+R& \mathrm{otherwise}\end{array}$

[0127] When L and NRB.sub.start.sup.(0) are decoded the terminal has defined the resource blocks allocated to it.

[0128] Of course, the present invention is not limited to the examples of embodiments described in details above, but encompasses also further alternative embodiments.

[0129] For example the present invention refers to carrier band of a specific bandwidth but the invention can also be implemented on a pre-defined portion of the entire carrier band, more specifically the pre-defined portion seen by a terminal as the maximum band where its own resource allocation and control signaling can occur.