Multiuser superposed transmission with flexible transport block size selection

1. A network node for a wireless communication system, the network node including a processor and a transceiver , the processor being configured to:

determine that a first channel quality indication (CQI 1 ) for a first user equipment is higher than a second channel quality indication (CQI 2 ) for a second user equipment;

determine a first modulation and coding scheme index (I MCS,N ) for the first user equipment based on a first set of modulation and coding schemes (MC 1 ), wherein the first set of modulation and coding schemes (MC 1 ) comprises:

a first range of transport block sizes [n 0 . . . n 1 ] mapped to a first modulation order Q m =q 0 ; and

at least a second range of transport block sizes [n 2 . . . n 3 ] mapped to a second modulation order Q m =q 1 , where q 1 >q 0 , and n 3 >=n 1 and n 2 <n 1 .

2. The network node according to claim 1 , wherein the first set of modulation and coding schemes (MC 1 ) further comprises a third range of transport block sizes [n 4 . . . n 5 ] mapped to a third modulation order Q m =q 2 , where q 2 >q 1 , and n 5 >=n 3 and n 4 <n 3 .

3. The network node according to claim 1 , wherein a smallest transport block size n x in the range of transport block sizes [n x . . . n y ] mapped to any modulation order Q m >q 0 is equal to transport block size n 0 in the first range of transport block sizes [n 0 . . . n 1 ], wherein n 0 is mapped to the first modulation order Q m =q 0 .

4. The network node according to claim 1 , wherein the transceiver is configured to send an activation mode signal to the first user equipment.

5. The network node according to claim 1 , wherein the transceiver is configured to send the first modulation and coding scheme index (I MCS,N ) to the first user equipment.

6. The network node according to claim 1 , wherein the processor is configured to determine a second modulation and coding scheme index (I MCS,F ) based on a second set of modulation and coding schemes (MC 2 ) for the second user equipment, and the transceiver is configured to send the second modulation and coding scheme index (I MCS,F ) to the second user equipment.

7. The network node according to claim 6 wherein the transceiver is configured to transmit a superposed signal based on the first modulation and coding scheme index (I MCS,N ) and the second modulation and coding scheme index (I MCS,F ).

8. The network node according to claim 1 , wherein a range of transport block size indices mapped to any modulation order Q m >q 0 in the first set of modulation and coding schemes (MC 1 ) is [0 . . . k], and a step between two consecutive transport block size indices is a function of a maximum transport block size index value k and a number of transport block size indices for modulation order Q m .

9. The network node according to claim 1 , wherein the range of transport block size indices mapped to any modulation order Q m >q 0 in the first set of modulation and coding schemes (MC 1 ) is [0 . . . k], and a transport block size index I TBS is determined based on a modulation and coding scheme index I MCS as I TBS =└k m (I MCS -n m )┘, where k m and n m are dependent on a modulation order Q m .

10. A first user equipment comprising:

a processor; and

a memory coupled to the processor and having processor-executable instructions stored thereon, which when executed by the processor, cause the first user equipment to:

receive an activation mode signal;

receive a first modulation and coding scheme index (I MCS,N ) based on a first set of modulation and coding schemes (MC 1 ), wherein the first set of modulation and coding set schemes (MC 1 ) comprises:

a first range of transport block sizes [n 0 . . . n 1 ] mapped to a first modulation order Q m =q 0 ; and

at least a second range of transport block sizes [n 2 . . . n 3 ] mapped to a second modulation order Q m =q 1 , where q 1 >q 0 , and n 3 >=n 1 and n 2 <n 1 ; and

determine a transport block size N TB,N and a modulation order Q m,N mapped to the first modulation and coding scheme index (I MCS,N ).

11. The first user equipment according to claim 10 , wherein the processor-executable instructions further cause the first user equipment to:

receive a superposed signal transmission based on the first modulation and coding scheme index (I MCS,N ) and a second modulation and coding scheme index (I MCS,F ) based on a second set of modulation and coding schemes (MC 2 );

cancel or suppress an interference of a second user signal on a first user signal from the received superposed signal transmission and obtain an interference cancelled signal; and

decode the interference cancelled signal based on the determined transport block size N TB,N and the determined modulation order Q m,N .

12. The first user equipment according to claim 11 , wherein the first set of modulation and coding schemes (MC 1 ) further comprises a third range of transport block sizes [n 4 . . . n 5 ] mapped to a third modulation order Q m =q 2 , where q 2 >q 1 , and n 5 >=n 3 and n 4 <n 3 .

13. The first user equipment according to claim 11 , wherein a smallest transport block size n x in the range of transport block sizes [n x . . . n y ] mapped to any modulation order Q m >q 0 is equal to transport block size n 0 in the first range of transport block sizes [n 0 . . . n 1 ], wherein n 0 is mapped to the first modulation order Q m =q 0 .

14. The first user equipment according to claim 11 , wherein the processor-executable instructions further cause the first user equipment to:

receive an activation mode signal form a network node.