Transmission block size determination
There is provided mechanisms for operation in a communication network. A method in a wireless device adapted for operation in the communication network comprises obtaining a pre-defined rule for computing a default transmission data block size on the basis of one or more input parameters selected from: a number of allocated physical resource blocks, a number of allocated time-domain symbols, an effective number of resource elements per physical resource block and/or symbol, a number of spatial layers, a modulation order, and a code rate.
1. A method of operating a wireless device in a communication network, the method comprising:
obtaining a pre-defined rule for computing a default transmission data block size based on one or more input parameters selected from:
a number of allocated physical resource blocks,
an effective number of resource elements per physical resource block and/or symbol,
a number of spatial layers,
a modulation order, and
a code rate; and
receiving first signaling at least partially overriding values obtained by the pre-defined rule, wherein the first signaling is received as:
a broadcast in a System Information Block transmission; or
a flag in a downlink control information (“DCI”) message and whether to limit the transmission data block size by partially overriding values obtained by the pre-defined rule depends on in which search space the DCI message is located.
2. The method of claim 1 , wherein obtaining includes receiving second signaling indicative of the pre-defined rule and/or at least one of its input parameters.
3. The method of claim 1 , wherein the pre-defined rule follows a pre-agreed specification of the communication network.
4. The method of claim 1 , wherein the pre-defined rule for computing the transmission data block size comprises a factor given by:
N PRB ·N RE ·v·Q m ·r,
where N PRB represents the allocated number of physical resource blocks, where N RE represents the effective number of resource elements per physical resource block, where v represents the number of spatial layers, where Q m represents the modulation order, and where r represents the code rate.
5. The method of claim 4 , wherein the pre-defined rule specifies the transmission data block size to be aligned with byte size.
6. The method of claim 4 , wherein the pre-defined rule for computing the transmission data block size is given by:
C
·
⌈
N
PRB
·
N
RE
·
v
·
Q
m
·
r
C
⌉
,
where ┌x┐ is a ceiling function, giving the smallest integer no smaller than x, and C is a positive integer representing a size unit.
7. The method of claim 6 , where C=8.
8. The method of claim 1 , wherein the first signaling indicates at least one combination of a Modulation and Coding Scheme (“MCS”) level and a resource allocation size and further indicates transmission data block size value associated with this combination.
9. The method of claim 8 , wherein the at least one combination of MCS level and resource allocation size is selected from combinations of MCS level and resource allocation size as stored in a fixed look-up table.
10. The method of claim 8 , wherein the at least one combination of MCS level and resource allocation size is selected from combinations of MCS level and resource allocation size as fixed in a specification of the communication network.
11. The method of claim 1 , wherein the first signaling is higher layer signaling.
12. The method of claim 1 , wherein the first signaling is received as broadcast in the System Information Block transmission.
13. The method of claim 1 , wherein the first signaling is received as the flag in the DCImessage.
14. The method of claim 13 , wherein the flag is a Radio Network Temporary Identifier.
15. The method of claim 1 , wherein the first signaling limits the transmission data block size to a formula given by:
C
·
⌈
N
PRB
·
N
RE
·
v
·
Q
m
·
r
C
⌉
,
where [χ] is a ceiling function, giving the smallest integer no smaller than χ, and C is a positive integer representing a size unit.
16. The method of claim 15 , where C=8.
17. The method of claim 9 , wherein whether to use the look-up table, a specification, or a formula depends on a bit in the DCI message.
18. The method of claim 1 , wherein the first signaling limits the transmission data block size to 144, 176, 208, 224, 256, or 328 bits.
19. The method of claim 8 , further comprising:
receiving a downlink assignment;
determining whether a combination of MCS level and a resource allocation size applicable for the downlink assignment corresponds to a combination indicated by the first signaling; and
responsive to a positive outcome of the determination, receiving downlink data in accordance with the downlink assignment applying a transmission data block size indicated by the first signaling.
20. The method of claim 1 , further comprising:
receiving downlink data from a node of the communication network while applying the default transmission data block.
21. A method of operating a network node in a communication network, the method comprising:
obtaining a pre-defined rule for computing a default transmission data block size based on one or more input parameters selected from:
a number of allocated physical resource blocks,
an effective number of resource elements per physical resource block and/or symbol,
a number of spatial layers,
a modulation order, and
a code rate; and
transmitting first signaling at least partially overriding values obtained by the pre-defined rule, wherein the first signaling is received as:
a broadcast in a System Information Block transmission; or
a flag in a downlink control information (“DCI”) message and whether to limit the transmission data block size by partially overriding values obtained by the pre-defined rule depends on in which search space the DCI message is located.
22. A wireless device for operation in a communication network, the wireless device comprising:
processing circuitry; and
memory coupled to the processing circuitry and having instructions stored therein that are executable by the processing circuitry to cause the wireless device to perform operations comprising:
obtaining a pre-defined rule for computing a default transmission data block size based on one or more input parameters selected from:
a number of allocated physical resource blocks,
an effective number of resource elements per physical resource block and/or symbol,
a number of spatial layers,
a modulation order, and
a code rate; and
receiving first signaling at least partially overriding values obtained by the pre-defined rule, wherein the first signaling is received as:
a broadcast in a System Information Block transmission; or
a flag in a downlink control information (“DCI”) message and whether to limit the transmission data block size by partially overriding values obtained by the pre-defined rule depends on in which search space the DCI message is located.
23. A network node for operation in a communication network, the network node comprising:
processing circuitry; and
memory coupled to the processing circuitry and having instructions stored therein that are executable by the processing circuitry to cause the network node to perform operations comprising:
obtaining a pre-defined rule for computing a default transmission data block size on one or more input parameters selected from:
a number of allocated physical resource blocks,
an effective number of resource elements per physical resource block and/or symbol,
a number of spatial layers,
a modulation order, and
a code rate; and
transmitting first signaling at least partially overriding values obtained by the pre-defined rule, wherein the first signaling is received as:
a broadcast in a System Information Block transmission; or
a flag in a downlink control information (“DCI”) message and whether to limit the transmission data block size by partially overriding values obtained by the pre-defined rule depends on in which search space the DCI message is located.
24. A non-transitory computer-readable medium having instructions stored therein that are executable by a processor of a wireless device, causes the wireless device to perform operations comprising:
obtaining a pre-defined rule for computing a default transmission data block size based on one or more input parameters selected from:
a number of allocated physical resource blocks,
an effective number of resource elements per physical resource block and/or symbol,
a number of spatial layers,
a modulation order, and
a code rate; and receiving first signaling at least partially overriding values obtained by the pre-defined rule, wherein the first signaling is received as:
a broadcast in a System Information Block transmission; or
a flag in a downlink control information (“DCI”) message and whether to limit the transmission data block size by partially overriding values obtained by the pre-defined rule depends on in which search space the DCI message is located.
25. A non-transitory computer-readable medium having instructions stored therein that are executable by a processor of a network node, causes the network node to perform operations comprising:
obtaining a pre-defined rule for computing a default transmission data block size based on one or more input parameters selected from:
a number of allocated physical resource blocks,
an effective number of resource elements per physical resource block and/or symbol,
a number of spatial layers,
a modulation order, and
a code rate; and
transmitting first signaling at least partially overriding values obtained by the pre-defined rule, wherein the first signaling is received as:
a broadcast in a System Information Block transmission; or
a flag in a downlink control information (“DCI”) message and whether to limit the transmission data block size by partially overriding values obtained by the pre-defined rule depends on in which search space the DCI message is located.
26. The method of claim 1 , wherein the one or more input parameters includes a number of allocated time-domain symbols.
27. The method of claim 21 , wherein the pre-defined rule for computing the transmission data block size comprises a factor given by:
N PRB ·N RE ·v·Q m ·r,
where N PRB represents the allocated number of physical resource blocks, where N RE represents the effective number of resource elements per physical resource block, where v represents the number of spatial layers, where Q m represents the modulation order, and where r represents the code rate.
28. The wireless device of claim 22 , wherein the pre-defined rule for computing the transmission data block size comprises a factor given by:
N PRB ·N RE ·v·Q m ·r,
where N PRB represents the allocated number of physical resource blocks, where N RE represents the effective number of resource elements per physical resource block, where v represents the number of spatial layers, where Q m represents the modulation order, and where r represents the code rate.