WO2025011744A1

WO2025011744A1 - Transmission of sets of code blocks using two carriers and processing of a code block for fitting to respective resources

Info

Publication number: WO2025011744A1
Application number: PCT/EP2023/069003
Authority: WO
Inventors: Karri Markus Ranta-Aho; Kamakshi LAKSHMINARAYANAPURAM KRISHNAKUMAR
Original assignee: Nokia Technologies Oy
Current assignee: Nokia Technologies Oy
Priority date: 2023-07-10
Filing date: 2023-07-10
Publication date: 2025-01-16
Anticipated expiration: 2026-01-10

Abstract

Disclosed is a method comprising receiving, from a medium access control layer, a transmission block to be transmitted using at least a first carrier and a second carrier, wherein the first carrier and the second carried are on different radio frequencies with respect to one another, determining a first set of code blocks for the first carrier and a second set of code blocks for the second carrier, wherein the code blocks of the first set are mapped to their respective resources of the first carrier, performing processing of at least one code block of the first set to cause at least a subset of the code blocks of the first set to fit to their respective resources of the first carrier, performing processing of the transmission block, the processing comprising mapping the transmission block to the first set and the second set of code blocks for transmission, and transmitting the transmission block using the first carrier and the second carrier.

Description

TRANSMISSION OF SETS OF CODE BLOCKS USING TWO CARRIERS AND PROCESSING OF A CODE BLOCK FOR FITTING TO RESPECTIVE RESOURCES

Field

The following exemplary embodiments relate to wireless communication and using at least two different carriers for transmission of data.

Background

In cellular communication networks, one base station may provide one or more cells. One cell may be serving one carrier, for example, in time division duplex (TDD) there is an unpaired band operation one bi-directional carrier, and in frequency division duplex (FDD) there is a paired band operation one carrier in downlink (DL), one carrier in uplink (UL). Additionally, carrier aggregation (CA) technologies may be utilized to enable carriers of multiple cells to be aggregated together towards one user equipment (UE) for increased data rate.

Brief Description

The scope of protection sought for various embodiments of the invention is set out by the independent claims. The exemplary embodiments and features, if any, described in this specification that do not fall under the scope of the independent claims are to be interpreted as examples useful for understanding various embodiments of the invention. The base station, or any other suitable radio unit in a wireless digital communication network that comprises multiple antennas for the wireless communication enabling transmission of data, may then use cross polarized antennas to enable independent transmission paths for data transmission.

According to a first aspect there is provided an apparatus comprising means for performing: receiving, from a medium access control layer, a transmission block to be transmitted using at least a first carrier and a second carrier, wherein the first carrier and the second carried are on different radio frequencies with respect to one another, determining a first set of code blocks for the first carrier and a second set of code blocks for the second carrier, wherein the code blocks of the first set are mapped to their respective resources of the first carrier, performing processing of at least one code block of the first set to cause at least a subset of the code blocks of the first set to fit to their respective resources of the first carrier, performing processing of the transmission block, the processing comprising mapping the transmission block to the first set and the second set of code blocks for transmission, and transmitting the transmission block using the first carrier and the second carrier.

In some example embodiments according to the first aspect, the means comprises at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, to cause the performance of the apparatus.

According to a second aspect there is provided an apparatus comprising at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, are configured to cause the apparatus at least to: receive, from a medium access control layer, a transmission block to be transmitted using at least a first carrier and a second carrier, wherein the first carrier and the second carried are on different radio frequencies with respect to one another, determine a first set of code blocks for the first carrier and a second set of code blocks for the second carrier, wherein the code blocks of the first set are mapped to their respective resources of the first carrier, perform processing of at least one code block of the first set to cause at least a subset of the code blocks of the first set to fit to their respective resources of the first carrier, perform processing of the transmission block, the processing comprising mapping the transmission block to the first set and the second set of code blocks for transmission, and transmit the transmission block using the first carrier and the second carrier.

According to a third aspect there is provided a method comprising: receiving, from a medium access control layer, a transmission block to be transmitted using at least a first carrier and a second carrier, wherein the first carrier and the second carried are on different radio frequencies with respect to one another, determining a first set of code blocks for the first carrier and a second set of code blocks for the second carrier, wherein the code blocks of the first set are mapped to their respective resources of the first carrier, performing processing of at least one code block of the first set to cause at least a subset of the code blocks of the first set to fit to their respective resources of the first carrier, performing processing of the transmission block, the processing comprising mapping the transmission block to the first set and the second set of code blocks for transmission, and transmitting the transmission block using the first carrier and the second carrier.

In some example embodiment according to the third aspect the method is a computer implemented method.

According to a fourth aspect there is provided a computer program comprising instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: receive, from a medium access control layer, a transmission block to be transmitted using at least a first carrier and a second carrier, wherein the first carrier and the second carried are on different radio frequencies with respect to one another, determine a first set of code blocks for the first carrier and a second set of code blocks for the second carrier, wherein the code blocks of the first set are mapped to their respective resources of the first carrier, perform processing of at least one code block of the first set to cause at least a subset of the code blocks of the first set to fit to their respective resources of the first carrier, perform processing of the transmission block, the processing comprising mapping the transmission block to the first set and the second set of code blocks for transmission, and transmit the transmission block using the first carrier and the second carrier.

According to a fifth aspect there is provided a computer program comprising instructions stored thereon for performing at least the following: receiving, from a medium access control layer, a transmission block to be transmitted using at least a first carrier and a second carrier, wherein the first carrier and the second carried are on different radio frequencies with respect to one another, determining a first set of code blocks for the first carrier and a second set of code blocks for the second carrier, wherein the code blocks of the first set are mapped to their respective resources of the first carrier, performing processing of at least one code block of the first set to cause at least a subset of the code blocks of the first set to fit to their respective resources of the first carrier, performing processing of the transmission block, the processing comprising mapping the transmission block to the first set and the second set of code blocks for transmission, and transmitting the transmission block using the first carrier and the second carrier.

According to a sixth aspect there is provided a non-transitory computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least the following: receive, from a medium access control layer, a transmission block to be transmitted using at least a first carrier and a second carrier, wherein the first carrier and the second carried are on different radio frequencies with respect to one another, determine a first set of code blocks for the first carrier and a second set of code blocks for the second carrier, wherein the code blocks of the first set are mapped to their respective resources of the first carrier, perform processing of at least one code block of the first set to cause at least a subset of the code blocks of the first set to fit to their respective resources of the first carrier, perform processing of the transmission block, the processing comprising mapping the transmission block to the first set and the second set of code blocks for transmission, and transmit the transmission block using the first carrier and the second carrier.

According to a seventh aspect there is provided a non-transitory computer readable medium comprising program instructions stored thereon for performing at least the following: receiving, from a medium access control layer, a transmission block to be transmitted using at least a first carrier and a second carrier, wherein the first carrier and the second carried are on different radio frequencies with respect to one another, determining a first set of code blocks for the first carrier and a second set of code blocks for the second carrier, wherein the code blocks of the first set are mapped to their respective resources of the first carrier, performing processing of at least one code block of the first set to cause at least a subset of the code blocks of the first set to fit to their respective resources of the first carrier, performing processing of the transmission block, the processing comprising mapping the transmission block to the first set and the second set of code blocks for transmission, and transmitting the transmission block using the first carrier and the second carrier.

According to an eighth aspect there is provided a computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least the following: receive, from a medium access control layer, a transmission block to be transmitted using at least a first carrier and a second carrier, wherein the first carrier and the second carried are on different radio frequencies with respect to one another, determine a first set of code blocks for the first carrier and a second set of code blocks for the second carrier, wherein the code blocks of the first set are mapped to their respective resources of the first carrier, perform processing of at least one code block of the first set to cause at least a subset of the code blocks of the first set to fit to their respective resources of the first carrier, perform processing of the transmission block, the processing comprising mapping the transmission block to the first set and the second set of code blocks for transmission, and transmit the transmission block using the first carrier and the second carrier.

According to a ninth aspect there is provided a computer readable medium comprising program instructions stored thereon for performing at least the following: receiving, from a medium access control layer, a transmission block to be transmitted using at least a first carrier and a second carrier, wherein the first carrier and the second carried are on different radio frequencies with respect to one another, determining a first set of code blocks for the first carrier and a second set of code blocks for the second carrier, wherein the code blocks of the first set are mapped to their respective resources of the first carrier, performing processing of at least one code block of the first set to cause at least a subset of the code blocks of the first set to fit to their respective resources of the first carrier, performing processing of the transmission block, the processing comprising mapping the transmission block to the first set and the second set of code blocks for transmission, and transmitting the transmission block using the first carrier and the second carrier.

List of Drawings

In the following, the invention will be described in greater detail with reference to the embodiments and the accompanying drawings, in which

FIG. 1 illustrates an example embodiment of a radio access network.

FIG. 2 illustrates an example embodiment of parallel processing of code blocks.

FIG. 3 illustrates an example embodiment of processing a transmission block.

FIG. 4A and FIG. 4B illustrate example embodiments in which code blocks are mapped such that none of them is spread across different carriers.

FIG. 4C illustrates a flow chart according to an example embodiment or processing a transmission block.

FIG. 5 illustrates an example embodiment in which a transmission block is mapped to code blocks and the code blocks are mapped to resource blocks.

FIG. 6 illustrates a flow chart according to an example embodiment of code block segmentation.

FIG. 7 illustrates an example embodiment of an apparatus.

Description of Embodiments

The following embodiments are exemplifying. Although the specification may refer to “an”, “one”, or “some” embodiment(s) in several locations of the text, this does not necessarily mean that each reference is made to the same embodiment(s), or that a particular feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments. As used in this application, the term ‘circuitry’ refers to all of the following: (a) hardware-only circuit implementations, such as implementations in only analog and/or digital circuitry, and (b) combinations of circuits and software (and/or firmware), such as (as applicable): (i) a combination of processor(s) or (ii) portions of processor(s)/software including digital signal processor(s), software, and memory(ies) that work together to cause an apparatus to perform various functions, and (c) circuits, such as a microprocessor(s) or a portion of a microprocessor(s), that require software or firmware for operation, even if the software or firmware is not physically present. This definition of ‘circuitry’ applies to all uses of this term in this application. As a further example, as used in this application, the term ‘circuitry’ would also cover an implementation of merely a processor (or multiple processors) or a portion of a processor and its (or their) accompanying software and/or firmware. The term ‘circuitry’ would also cover, for example and if applicable to the particular element, a baseband integrated circuit or applications processor integrated circuit for a mobile phone or a similar integrated circuit in a server, a cellular network device, or another network device. The above-described embodiments of the circuitry may also be considered as embodiments that provide means for carrying out the embodiments of the methods or processes described in this document.

The techniques and methods described herein may be implemented by various means. For example, these techniques may be implemented in hardware (one or more devices), firmware (one or more devices), software (one or more modules), or combinations thereof. For a hardware implementation, the apparatus(es) of embodiments may be implemented within one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), graphics processing units (GPUs), processors, controllers, microcontrollers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof. For firmware or software, the implementation can be carried out through modules of at least one chipset (e.g. procedures, functions, and so on) that perform the functions described herein. The software codes may be stored in a memory unit and executed by processors. The memory unit may be implemented within the processor or externally to the processor. In the latter case, it can be communicatively coupled to the processor via any suitable means. Additionally, the components of the systems described herein may be rearranged and/or complemented by additional components in order to facilitate the achievements of the various aspects, etc., described with regard thereto, and they are not limited to the precise configurations set forth in the given figures, as will be appreciated by one skilled in the art.

Embodiments described herein may be implemented in a communication system, such as in at least one of the following: Long Term Evolution (LTE), LTE -Advanced, a fifth generation (5G) mobile or cellular communication system, 5G-Advanced and/or 6G. The embodiments are not, however, restricted to the systems given as an example but a person skilled in the art may apply the solution to other communication systems provided with necessary properties.

FIG. 1 depicts examples of simplified system architectures showing some elements and functional entities, the entities being logical units, whose implementation may differ from what is shown. The connections shown in FIG. 1 are logical connections; the actual physical connections may be different. It is apparent to a person skilled in the art that the system may comprise also other functions and structures than those shown in FIG. 1. The example of FIG. 1 shows a part of an example embodiment of a radio access network.

FIG. 1 shows terminal devices 100 and 102 configured to be in a wireless connection on one or more communication channels in a cell with a base station (such as (e/g)NodeB) 104 providing the cell. The terminal devices 100 and 102 may also be called as mobile device, or user equipment (UE), or user terminal, user device, etc. The base station 104 may also be referred to as a node, or an access node, or any other type of interfacing device including a relay station capable of operating in a wireless environment. The physical link from a terminal device to a (e/g)NodeB is called uplink (UL) or reverse link and the physical link from the (e/g)NodeB to the terminal device is called downlink (DL) or forward link. It should be appreciated that (e/g)NodeBs or their functionalities may be implemented by using any access node, host, server or access point etc. entity suitable for such a usage. It is to be noted that although one cell is discussed in this exemplary embodiment, for the sake of simplicity of explanation, multiple cells may be provided by one access node in some example embodiments.

A communication system may comprise more than one (e/g)NodeB in which case the (e/g)NodeBs may also be configured to communicate with one another over links, wired or wireless, designed for the purpose. These links may be used for signalling purposes. The (e/g)NodeB is a computing device configured to control the radio resources of communication system it is coupled to. The (e/g)NodeB includes or is coupled to transceivers. From the transceivers of the (e/g)NodeB, a connection is provided to an antenna unit that establishes bi-directional radio links to user devices (UEs). The antenna unit may comprise a plurality of antennas or antenna elements. The (e/g)NodeB is further connected to core network 110 (CN or next generation core NGC). Depending on the system, the counterpart on the CN side maybe a serving gateway (S-GW, routing and forwarding user data packets), packet data network gateway (P-GW), for providing connectivity of terminal devices to external packet data networks, or mobile management entity (MME), etc.

The user equipment (UE) illustrates one type of an apparatus to which resources on the air interface are allocated and assigned, and thus any feature described herein with a UE may be implemented with a corresponding apparatus, such as a relay node. An example of such a relay node is a layer 3 relay (self-backhauling relay) towards the base station. Another example of such a relay node is a layer 2 relay. Such a relay node may comprise a UE part and a Distributed Unit (DU) part. A CU (centralized unit) may coordinate the DU operation via F1AP -interface for example. The UE may refer to a portable computing device that includes wireless mobile communication devices operating with or without a subscriber identification module (SIM), or an embedded SIM, eSIM. A UE may also be a device having capability to operate in Internet of Things (loT) network which is a scenario in which objects are provided with the ability to transfer data over a network without requiring human- to-human or human-to-computer interaction. The UE may also utilise cloud computing. The UE (or in some embodiments a layer 3 relay node) is configured to perform one or more of user equipment functionalities. It is to be noted that the UE may also be a vehicle or a household appliance capable of using cellular communication.

Additionally, although the apparatuses have been depicted as single entities, different units, processors and/or memory units (not all shown in FIG. 1) may be implemented.

The communication system may also able to communicate with other networks, such as a public switched telephone network or the Internet 112, and/or utilise services provided by them. The communication network may also be able to support the usage of cloud services, for example at least part of core network operations may be carried out as a cloud service (this is depicted in FIG. 1 by “cloud” 114). The communication system may also comprise a central control entity, or a like, providing facilities for networks of different operators to cooperate for example in spectrum sharing. It is also possible that node operations will be distributed among a plurality of servers, nodes or hosts. Application of cloudRAN architecture enables RAN real time functions being carried out at the RAN side (in a distributed unit, DU 104) and non-real time functions being carried out in a centralized manner (in a centralized unit, CU 108).

It is to be noted that the depicted system is an example of a part of a radio access system and the system may comprise a plurality of (e/g)NodeBs, Ues may have access to a plurality of radio cells and the system may comprise also other apparatuses, such as physical layer relay nodes or other network elements, etc. Additionally, in a geographical area of a radio communication system a plurality of different kinds of radio cells as well as a plurality of radio cells may be provided. Radio cells may be macro cells (or umbrella cells) which are large cells, usually having a diameter of up to tens of kilometers, or smaller cells such as micro-, femto- or picocells. The (e/g)NodeBs of FIG. 1 may provide any kind of these cells. A cellular radio system may be implemented as a multilayer network including several kinds of cells. In some exemplary embodiments, in multilayer networks, one access node provides one kind of a cell or cells, and thus a plurality of (e/g)NodeBs are required to provide such a network structure.

Although different cellular communication technologies allow CA to be used towards a UE for increased data rate, the aggregation may be achieved by operating separate independent cells in parallel and thus there may still be considered to be one cell per one carrier. Therefore, hardware (HW) resources that are for processing layer 1 (LI) may be deployed per carrier, and transport blocks (TB) that are processed for transmission and reception may be processed in parallel HW units, which may also be considered as logical unit. In CA, the data to be transported may be divided to cellspecific, in other words carrier-specific, transport blocks (TBs), which may be processed for transmission independently. When there are independent TBs per one carrier, the parallel processing of TBs may be considered to be supported naturally. Yet, in case a TB is to be mapped to a cell that has multiple carriers and those carriers are on different frequency blocks, then further processing is required for the parallelization. The different frequency blocks may be contiguous or non-contiguous. Thus, the one TB is to be mapped to two, or more, carriers for transmission.

FIG. 2 illustrates a simplified example embodiment of parallel processing of code blocks (CBs). In this example embodiment, a TB 210 is received from a medium access control (MAC) layer. Then a cyclic redundancy check (CRC) is calculated and attached to the TB 210 as illustrated in step 215, producing a set of bits 220 comprising the TB 210 and the CRC. In other words, the TB 210 may comprise n number of bits and the CRC may comprise m number of bits. The set of bits 220 thus comprises n+m number of bits. Then the set of bits 220, is subjected to CB segmentation, as illustrated in step 230. For the segmentation, it may be sufficient to know the size of the TB to be able to determine the CBs. As the receiver is also able to determine where the CBs are based on scheduling information, it is not necessary to go through code blocks sequentially from the first CB to the last CB to find the next CB. The TB is thus divided into the CBs 232, 234, 236 and 238 after which low density parity check (LPDC) encoding is performed as illustrated in step 240. In this example embodiment, each CB 232, 234, 236 and 238 is independently encoded, which allows for parallelization of channel encoding in the transmitter, and correspondingly decoding in the receiver. Thus, the obtained encoded CBs 242, 244, 246 and 248 may be concatenated, as illustrated in step 250, for further processing for transmitting. This may be understood as a logical operation and the subsequent steps may alternatively be implemented individually per encoded code block or per a group of encoded code blocks. In this example embodiment, the concatenation results in the encoded TB 260, for which scrambling 265 is performed to obtain a scrambled TB 270. Then in step 275 modulation, layer and port mapping is performed after which modulation symbols per layer per antenna port 280 are obtained. Then in step 285 mapping to resource blocks (RBs) is performed to obtain modulation symbols per carrier 290 for the transmission.

FIG. 3 illustrates an example embodiment in which processing of a TB received from a MAC layer is illustrated for two different scenarios 300 and 350. In scenario 300 there is parallel processing, which may be used when CA is utilized. In scenario 350, the processing is jointly performed for two different carriers when CA is used with a cell aggregating different carriers. The different carriers may be understood to be on different radio frequencies. In other words, there may be multiple, frequency blocks, such as non-contiguous frequency blocks, mapped to a cell and thus the processing may be performed jointly.

In scenario 300, two separate TBs 310 and 315 are processed in two parallel processes, one for a first carrier 340, which is (transmit) Tx carrier, and one for a second carrier 345, which is also a Tx carrier. The size of the TB 310 may be the same as the size of the TB 315 or it may be different. The TB 310 andTB 315 in this example embodiment carry different sets of data bits. Thus, for the carrier 340, the TB 310 is processed by performing LI processing 320 and RB mapping 330, and for the carrier 345 the TB 315 is processed by performing LI processing 325 and RB mapping 335.

In scenario 350, the TB 360 is processed together for the carrier 340 and for the carrier 345. The TB 360 in this example embodiment has a size that is equivalent, or substantially corresponds to the combined size of the TB 310 and TB 315. Thus, the TB 310 is processed by performing LI processing 370 and RB mapping 380. In this scenario it is also to be ensured that each CB maps to one contiguous frequency spectrum block to allow for parallel encoding and decoding processing on a per- spectrum-block, in other words, per carrier, basis. Thus, TB 360, after encoding, leads to N CBs to be mapped on a plurality of spectrum blocks, in other words, carriers. Unless specific steps are taken, this may lead to one CB being mapped such that part of it is on one carrier and another part on another carrier: For example, CBs #l...#n- 1 may fit fully on carrier 1, then CB n would spread on both carriers, and CBs #n+l...#N may then fit fully on carrier 2. Yet, it may be desirable to have each CB mapped fully on one carrier instead of multiple carriers.

It is to be noted that mapping a TB to one or more CBs may be understood as comprising segmenting the TB such that in the bit-sequence, that is the TB, boundaries of the one or more CBs are determined. This may be sufficient such that no data is to be moved or manipulated in some additional ways. After this, the one or more CBs are encoded by feeding them to an encoder. The encoding may be performed in parallel, in serial manner, or using a combination of both. For example, there may be X number of encoders encoding Y number of CBs, where X is fixed in the hardware design and Y depends on the TB size and can be greater than X.

It is also to be noted that when a CB fits to its respective resources available on a carrier, it may be understood that the CB exactly matches the capacity of its respective resources, or the CB is processed such that it fits to its respective resources, the processing of the CB may comprise for example truncating the CB, modifying the CB, and/or adapting the CB for example by adapting its modulation and coding scheme (MCS). It is also to be noted that if a CB fits in its respective resources, it may be understood such that the CB fits fully, but there may still be resources left.

If a CB comprises N bits before encoding, then after encoding the CB may be the size of M bits, where N<M. In some examples, it is possible not to transmit all the M bits if the actually transmitted number of encoded bits is still greater than N. This way it may be possible to decode the CB at the receiver, depending on the number of bit errors and, in some examples, also to some extent on which bits out of the M bits not transmitted.

In case one TB is to be transmitted using at least two carriers, carrier 1 and carrier 2, the transmission may not be sequential between the two carriers, but may be at least partially time-overlapping. When determining the fitting of one or more CBs to its respective resources, may comprise determining the chosen MCS, allocated resources to transmit the TB on the carriers and based on this it may be determined where the CB boundaries are before encoding of any of the CBs. It may also be determined how many bits each CB is after encoding.

FIG. 4A illustrates an example embodiment in which CBs are mapped such that none of them is spread across different carriers. In other words, such that none of the CBs are transmitted using resources from more than one carrier of the different carriers, but that each CB is transmitted using resources of one carrier. In yet other words, the CBs are transmitted using resources that are available on one carrier. In this example embodiment, TB 400 that is received from MAC is processed by performing LI processing as illustrated in block 410. After this, the mapping of CBs to resource blocks (RBs), which may be understood as resources, is performed. The mapping in this example embodiment is CB-aware RB mapping illustrated as block 415. The CB- aware mapping maps the CBs to the RBs of the carriers such that in case a CB would be mapped to two carriers, the first carrier 420 and the second carrier 425, because there are not enough resources left in the first carrier 420 to fit that CB fully into the resources of the first carrier 420, the CB is shifted to start from the beginning of the resources second carrier 425. In other words, the CB is moved completely to the resources of the second carrier 425, and consequently, a subset of the CBs mapped to the resources of the first carrier 420 fit the first carrier 420 and are transmitted using the first carrier. This avoids splitting the CB onto two different carriers. The resource elements (REs), which may be understood as resources, of the first carrier 420 that would have carried part of the CB may be left unused. Then scheduling may be performed such that it minimizes the amount of waste by taking this into account.

Various options may then be utilized to address the aspect of some of the RBs being left unused. One example option is that additional REs are allocated to the second carrier 425 to fit the CB as well as other remaining CBs. The allocation may be performed automatically. The scheduler may then take into account the resource allocation as it may be aware of this. Another example option is that the remaining CBs are truncated, in other words, the bits of the CB that do not fully fit to the first carrier are not transmitted. In this option, additional REs may not be allocated to the second carrier 425. The scheduler may be aware of this and may take it into account in the resource allocation to minimize the number of bits cut.

A further example option is that the code rate of the remaining CBs are adapted to the available resources on the physical layer. The adapting may thus allow larger number of bits to fit the resources available on the second carrier. In this option, additional REs may not be allocated to the second carrier 425. The scheduler may be aware of this and may take it into account in the resource allocation to reach the desired modulation and coding scheme (MCS).

It is also to be noted that in some example embodiments, the code rate of the CBs allocated to their respective resources available in the first carrier 420 may also be adjusted, by for example increasing the code rate, to ensure that the CBs fit to those resources.

FIG. 4B illustrates another example embodiment in which CB are mapped such that they are not spread across different carriers. It is to be noted that there may be two or more carriers that are used to transmit a TB. In this example embodiment, TB 400 that is received from MAC is processed by performing spectrum block-aware CB segmentation as illustrated in block 430. In the spectrum block -aware segmentation the TB 410 is segmented to CBs so that the size of the last CB to be mapped to the first carrier 420 is adjusted such that it fits to the first carrier 420 and does not flow over to the second carrier 425. This adjustment may be performed such that the last CB fills the remaining resources of the first carrier 420, which are allocated to transmission of the TB, in an exact manner, which may be understood as fitting exactly, or fitting perfectly. The segmentation may be performed after CRC attachment. In this example embodiment, the size of the last CB is determined such that it fills the remaining allocated REs on the first carrier 420 after accounting for the resources needed for CBs up to the last CB to be allocated to the first carrier 420.

The processing of the TB 400 then continues by performing LI processing as illustrated by block 440 and then performing RB mapping as illustrated in block 450. After this, the transmission is performed using the first carrier 420 and the second carrier 425. Optionally, also the last CB allocated for the second carrier 425 may be processed such that its size is adjusted to fit the resources allocated in the second carrier 425. The adjustments may be performed such that the last CB allocated for the second carrier 425 fits the resources in an exact manner.

It is also to be noted that in some example embodiments, the code rate of the CBs allocated to their respective resources available in the first carrier 420 may also be adjusted, by for example increasing the code rate, to ensure that the CBs fit to those resources. FIG. 4C illustrates a flow chart according to an example embodiment in which TB is processed such that a CB is not allocated to two different carriers, when a TB is processed and mapped on to at least two different carriers.

In this example embodiment, in step 460, a TB is received from MAC layer and split into a plurality of sub-TBs. Then it is determined that if there are sub-TBs that are to be processed, as illustrated in step 465. A sub-TB may be understood as one part of the TB, such as a part allocated to one or more CBs associated with one carrier. If yes, then the one sub-TB is processed by mapping it to one or more CBs as illustrated in step 470. After this, matching of CBs to their respective resources available on their respective carriers is performed as illustrated in step 480. The matching, which may also be understood as processing, may be performed for example by using one or more of the following: adaptation of resource allocation, CB truncation, rate matching and CB size adaption.

It is to be noted that allocation of resources in each carrier for transmitting data to a UE is performed by a scheduler of a base station. The allocation may be performed per carrier, and it may be a function of overall available resources on the carrier and other traffic the scheduler decides to multiplex on that carrier at the same time. The MCS may be determined by the scheduler based on channel conditions to match targeted transmission success probability. As the allocated resources and the modulation order are known, it may be determined how many coded bits are to be transmitted, and the coding scheme determines the ratio of uncoded-bits to coded- bits. Thus, for example in the example embodiments described above, it may be determined how many coded bits fit on the first carrier and how many on the second carrier. Based on this it may be determined how many uncoded bits fit the carriers, then such a TB may be selected that fits to the carriers. This may be based on counting in the overhead coming from CRC(s), and then the TB may be split to sub-TBs so that they fit each carrier. The fitting may be fitting exactly. The example embodiments of FIG. 4A-4C allow a single cell to control resources across multiple carriers, which may correspond to carriers on different frequency bands, and achieve aggregation of fragmented frequency spectrum blocks without additional signaling overhead. This may also allow fast scheduling and flexibility in scheduling time and/or frequency resources across one or more blocks. This may allow efficient use of frequency spectrum blocks, which may be non-contiguous or contiguous. When frequency spectrum for scheduling a transmission is available as non-contiguous blocks, the scheduler may consider one TB that spreads across the spectrum blocks, or multiple TBs with one or more TBs per each spectrum-block. Multiple TBs may come with additional overhead bits to be provided in the scheduling information provided using downlink control information (DC1).

FIG. 5 illustrates an example embodiment in which a TB 500 is mapped to CBs 540 and RBs 550 that are on different fragments of frequency spectrum. The TB 500 has CRC attached to it and in this example embodiment it is mapped across multiple different carriers. In this example embodiment, there are three carriers, in other words, the frequency spectrum is fragmented into three different non-contiguous parts. The TB 500 in this example embodiment is mapped to the CBs 540, and the CBs 510 and 512 are CBs for the first carrier, the CBs 520, 522 and 524 are CBs for the second carrier and the CB 530 is for the third carrier. The CB 510 is then mapped to RBs 560, the CB 512 is mapped to the RBs 562, the CB 520 is mapped to the RBs 570, the CB 522 is mapped to the RBs 572, the CB 524 is mapped to the RBs 574 and the CB 530 is mapped to the RBs 580.

In this example embodiment, a packet scheduler is aware of the three carriers available that may be used to transmit data. It is also aware of the channel quality of each carrier and may thus base the scheduling decisions and MCS selection on channel quality. For DL, the channel quality of each carrier may be obtained from UE channel state measurement reports of a UE, or based on base station’s measurements of the uplink transmissions. For UL, the channel quality of each carrier may be obtained from measurements of the uplink transmissions of a base station in which the scheduler is comprised. When the scheduler decides to allocate a set of frequency resources for a specific time duration for transmission to a UE, it determines the MCS to be used in the transmission. The MCS may be common across the three carriers, or it may be different for different carriers. The allocated time and/or frequency resources together with the allocated MCS(s) thus determine unambiguously the number of information bits that can be transmitted. The CBs 540 are generated then from the TB 500 so that each code block is mapped to one and contiguous spectrum block, in other words, to one of the three carriers.

When a TB is to be transmitted using different carriers, for example two different carriers, the first carrier and the second carrier, the TB into a first set of CBs and a second set of CBs, the first set of CBs being mapped to the resources of the first carrier and the second set of CBs being mapped to the resources of the second carrier. In an example embodiment, it is then determined how to ensure that CBs from the first set are not transmitted using resources of both the first and the second carrier, but instead, each CB of the first set is transmitted using resources of just one of the carriers. In this example embodiment, two options may be taken. In the first option at least one CB of the first set is processed. For example, the processing is performed to the last CB, CB #n, of the first set. The processing may be for example of the following three alternatives: 1) the CB #n is moved completely to the second carrier, and additional resources are allocated to the second carrier; 2) the CB #n is truncated; and/or 3) code rate of the CB #n is adapted. As a second option in this example embodiment, the size of at least the CB #n of the first set is adjusted.

It is to be noted that the first option, and its three alternatives, may be combined with the second option as well. The combinations may comprise at least one of the alternatives of the first option, and the second option. Additionally, or alternatively, when determining how to ensure that the CBs of the first set are transmitted using resources of just one of the carriers, there may be a prioritisation that is applied with respect to the first option, and its alternatives, and the second option. Thus, for example, there may be a priority associated with the alternatives of the first option and with the second option. It is to be noted that also combinations of the first option, and its alternatives, as well as the second option, may be associated with a priority. Then, the approach of the highest alternative is considered first, but if determined not to be applicable, then the second highest alternative is considered, and if that one is not applicable either, then the third highest priority is considered, and so on. For example, one alternative of the first option may be considered first, based on the associated priorities, and if not possible, due to lack of additional resources for example, or not beneficial, then the second option is considered as fallback. Or as another example, based on the priority associated with the second option, the second option is considered first, but if no applicable, then one alternative of the first option is considered, and so on.

FIG. 6 illustrates a flow chart according to an example embodiment of code block segmentation. In this example embodiment, a TB is to be transmitted using at least two carriers and the at least two carriers may be fragmented in a frequency spectrum. In step 600 of this flow chart, a TB is received from a MAC layer. The TB is to be transmitted to a receiver over the air. The TB is received with accompanying information such as an indication of the number of carriers and MCS per each carrier. Then, in step 610, sizes of sub-TBs of the TB received are determined. The sizes may be bits per carrier. After this, in step 620, a CB size for each carrier is determined. In step 630 then the number of CBs for each carrier is determined. The determination may be performed based on one or more of the following; available REs, modulation order, or code rate of each carrier.

In step 635 it is then determined if there are additional bits after determining the number of CBs for one carrier. In case one the CBs, the last CB for the said carrier, would be partially allocated to another carrier, then, in this example embodiment, then that CB is allocated to the next carrier. If there are additional bits left, then the flow chart proceeds to step 640 in which input bits for the next carrier are determined, after which the process returns to step 620. In case there are no additional bits, then the flow chart proceeds to step 650 that comprises encoding and further processing CBs such that each CB carry a CRC of L bits. The size of the CRC may be fixed, or it may depend on for example a base graph selected. Per each carrier, the number of CBs may vary depending on one or more of the following: the physical resource blocks (PRBs) allocated per fragment, the used MCS, or the base graph selected. Then, in step 660 the CBs are mapped to the allocated PRBs so that CBs are not divided to another carrier.

It is to be noted that while retrieving the TB at a receiver, CBs from multiple spectrum-blocks are to be concatenated and a 24-bit CRC may be deducted to retrieve the entire transport block.

FIG. 7 illustrates an example embodiment of an apparatus that may be an access node or be comprised in an access node such as a gNB. The apparatus may be, for example, a circuitry or a chipset applicable to an access node to realize the described embodiments. The apparatus 700 may be an electronic device comprising one or more electronic circuitries. The apparatus 700 may comprise a communication control circuitry 710 such as at least one processor, and at least one memory 720 including a computer program code (software) 722 wherein the at least one memory and the computer program code (software) 722 are configured, with the at least one processor, to cause the apparatus 700 to carry out any one of the example embodiments of the access node described above.

The memory 720 may be implemented using any suitable data storage technology, such as semiconductor-based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The memory may comprise a configuration database for storing configuration data. For example, the configuration database may store current neighbour cell list, and, in some example embodiments, structures of the frames used in the detected neighbour cells. The apparatus 700 may further comprise a communication interface 730 comprising hardware and/or software for realizing communication connectivity according to one or more communication protocols. The communication interface 730 may provide the apparatus with radio communication capabilities to communicate in the cellular communication system. The communication interface may, for example, provide a radio interface to terminal devices. The apparatus 700 may further comprise another interface towards a core network such as the network coordinator apparatus and/or to the access nodes of the cellular communication system. The apparatus 700 may further comprise a scheduler 740 that is configured to allocate resources.

Even though the invention has been described above with reference to examples according to the accompanying drawings, it is clear that the invention is not restricted thereto but can be modified in several ways within the scope of the appended claims. Therefore, all words and expressions should be interpreted broadly and they are intended to illustrate, not to restrict, the embodiment. It will be obvious to a person skilled in the art that, as technology advances, the inventive concept can be implemented in various ways. Further, it is clear to a person skilled in the art that the described embodiments may, but are not required to, be combined with other embodiments in various ways.

Claims

1. An apparatus comprising at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, are configured to cause the apparatus at least to: receive, from a medium access control layer, a transmission block to be transmitted using at least a first carrier and a second carrier, wherein the first carrier and the second carried are on different radio frequencies with respect to one another; determine a first set of code blocks for the first carrier and a second set of code blocks for the second carrier, wherein the code blocks of the first set are mapped to their respective resources of the first carrier; perform processing of at least one code block of the first set to cause at least a subset of the code blocks of the first set to fit to their respective resources of the first carrier; perform processing of the transmission block, the processing comprising mapping the transmission block to the first set and the second set of code blocks for transmission; and transmit the transmission block using the first carrier and the second carrier.

2. An apparatus according to claim 1, wherein the apparatus is further caused to process the at least one code block of the first set by moving the code block completely to a beginning of resources of the second carrier.

3. An apparatus according to claim 2, wherein the apparatus is further caused to leave resources of the first carrier unused when the said at least one code block of the first set is moved completely to the beginning of the resources of the second carrier.

4. An apparatus according to claim 3, wherein the apparatus is further caused to allocate additional resource elements to the second carrier to fit the second set of code blocks and the said at least one code block moved to the second carrier.

5. An apparatus according to claim 3, wherein a last code block of the second set of code blocks is truncated to fit to the resources of the second carrier.

6. An apparatus according to claim 3, wherein code rate of the second set of code blocks is adapted to the resources available on the second carrier.

7. An apparatus according to claim 6, wherein code rate of the said at least one code block is also adapted to the resources available on the second carrier.

8. An apparatus according to claim 1, wherein the apparatus is further caused to process the at least one code block of the first set by increasing the code rate.

9. An apparatus according to claim 1, wherein the apparatus is further caused to process the at least one code block of the first set by determining its size to fit its respective resources of the first carrier.

10. An apparatus according to claim 9, wherein the at least one code block of the first set is the last code block of the first set and wherein its size is determined after accounting for resources required for the other code blocks of the first set and its size is determined to fit the said respective resources in an exact manner.

11. An apparatus according to any of the claims 8 to 10, wherein the at least the subset of the first set of code blocks comprises the first set of code blocks entirely.

12. An apparatus according to any previous claim, wherein the apparatus is further caused to process at least one code block of the second set by determining its size to fit its respective resources available on the second carrier.

13. An apparatus according to claim 12, wherein the at least one code block of the second set is the last code block of the second set and wherein its size is determined after accounting for resources required for the other code blocks of the second set and its size is determined to fit the said respective resources in an exact manner.

14. An apparatus according to any previous claim, wherein the transmission block comprises a cyclic redundancy check.

15. An apparatus according to any previous claim, wherein the transmission block is received with accompanying information regarding at least one of frequency allocation and modulation and coding scheme.

16. An apparatus according to any previous claim, wherein determining the first set of code blocks comprises determining the amount of code blocks in the first set of code blocks and their sizes, and determining the second set of code blocks comprises determining the amount of code blocks in the second set of code blocks and their sizes.

17. A method comprising: receiving, from a medium access control layer, a transmission block to be transmitted using at least a first carrier and a second carrier, wherein the first carrier and the second carried are on different radio frequencies with respect to one another; determining a first set of code blocks for the first carrier and a second set of code blocks for the second carrier, wherein the code blocks of the first set are mapped to their respective resources of the first carrier; performing processing of at least one code block of the first set to cause at least a subset of the code blocks of the first set to fit to their respective resources of the first carrier; performing processing of the transmission block, the processing comprising mapping the transmission block to the first set and the second set of code blocks for transmission; and transmitting the transmission block using the first carrier and the second carrier.

18. A computer program comprising instructions which, when executed by an apparatus, cause the apparatus to perform at least the following: receive, from a medium access control layer, a transmission block to be transmitted using at least a first carrier and a second carrier, wherein the first carrier and the second carried are on different radio frequencies with respect to one another; determine a first set of code blocks for the first carrier and a second set of code blocks for the second carrier, wherein the code blocks of the first set are mapped to their respective resources of the first carrier; perform processing of at least one code block of the first set to cause at least a subset of the code blocks of the first set to fit to their respective resources of the first carrier; perform processing of the transmission block, the processing comprising mapping the transmission block to the first set and the second set of code blocks for transmission; and transmit the transmission block using the first carrier and the second carrier.