TECHNICAL FIELD

The present disclosure relates to wireless communications, and in particular, to codeword-to-layer mapping.

BACKGROUND

Similar to Long Term Evolution (LTE)(the Third Generation Partnership Project (3 GPP) 4 ^th Generation (4G) mobile radio system), New Radio (NR) (the 3 GPP 5 ^th Generation 5G mobile radio system) may support device-to-device communication, often referred to as sidelink (SL) communication. Unlike in LTE, NR SL may be designed to handle more general type of communication covering not only group and broadcast, but also unicast. Additionally, NR SL communications may be expected to be used for a number of different services related to, e.g., vehicle-to- vehicle communication and public safety. Also, by enabling unicast transmissions, the NR SL may also provide for new services. To cater to these many different use cases, and to help ensure NR SL may be applied to further use cases, the physical layer may need to be designed in such a way that allows for flexibility and configurability. Additionally, the physical layer design may be designed to help secure high performance communication, and efficient implementation in the device.

In the area of channel coding, different sets of bits of a code word, originating from a sequence of information bits, can be formed to create different redundancy versions (RVs). The formation of these RVs may be performed by reading out information from a circular buffer. FIG. l is a diagram of different redundancy versions read out from a circular buffer of code word bits. Some of these sets of bits of the code word carry sufficient information such that the original information bits can be obtained. These RVs are referred to as being self-decodable. Some other RVs may not be self-decodable, but combined with a self-decodable RV so as to help increase the probability of correctly decoding the information bits.

In mobile radio systems like NR, reference signals for coherent demodulation of physical layer control and data channels signals are transmitted within an OFDM waveform. The reference signal (RS) is multiplexed with the physical layer channels and mapped on the OFDM time-frequency resource grid, in a predefined manner. In NR SL, sidelink control information (SCI) is divided into two parts, SCI1 and SCI2. The first SCI (SCI1) is transmitted over the physical sidelink control channel (PSCCH), which has a dedicated set of demodulation RS (DMRS), while the second SCI (SCI2) shares DMRS with the data channel PSSCH.

When the data channel is transmitted over multiple spatial Multiple-Input Multiple-Output (MIMO) layers, each layer may need to have its own associated DMRS antenna port. Since the data transmitted in a given layer is precoded with the same precoder as the associated DMRS, the data may be referred to as being transmitted on the associated DMRS port. The receiver at the entity receiving the signal may use the associated port when demodulating the data symbols of a layer. Precoding in this context may mean applying amplitude and/or phase shifts on each of the multiple antennas transmitting a signal.

Since SCI2 is transmitted together with the data channel, schemes to multiplex these two may be needed. For multi-layer transmission, different schemes could be used for the control channel, single layer mapping, single layer mapping with power boosting, and multi-layer mapping. FIGS. 2a-2c are diagrams of different multi-layer transmission schemes that include the following: (a) Single layer transmission with power boosting, (b) single layer mapping, and (c) multi-layer mapping.

In order to demodulate and decode the data channel, both SCIs may need to be decoded first. The decoding latency of the control channel may be kept low, in order to minimize the overall latency.

Existing solutions include: (1) single layer transmission with power boosting, (2) single layer transmission with data spatially multiplexed on other layers, and (3) multiplexing similar to PSSCH on the different layers. However, these existing solutions suffer from one or more of the following problems:

(1) the channel condition of the selected spatial layer may be poor, resulting in a low received power despite power boosting.

(2) partly similar to that of (1), but reliability is even worse since power is shared with PSSCH, and inter-layer interference.

(3) despite improving reliability through spatial diversity, the symbols in all layers need to be processed before decoding SCI2. Therefore, existing solutions do not allow for flexibility in mapping to adapt to the channel conditions, for example.

SUMMARY

Some embodiments advantageously provide methods, systems, and apparatuses for codeword-to-layer mapping, for example, based at least in part on at least one characteristic.

In one or more embodiments of the disclosure allows for adaptively changing the codeword-to-layer mapping of SCI2. The mapping may involve an entire codeword, or a number of redundancy versions (RV) of an underlying codeword. The mapping could make use of all, or a subset of layers.

In one or more embodiments, the algorithms for selecting the mapping scheme may be based at least in part on the knowledge of the channel state information at the wireless device, obtained through measurements or reports. The used mapping scheme could be signaled by a transmitting terminal in SCI1, or could be given by an earlier report by the receiving wireless device. Alternatively, the mapping could be given by semi-static (e.g., RRC) control signaling.

Additionally, if the channel code supports transmission of different redundancy versions (RV), transmitting different RVs of the same SCI codeword (CW) on different spatial layers may allow for improved reliability (as compared with known arrangements) through spatial diversity gains, as well as allow for reduced complexity of the decoding by allowing parallel or sequential decoding of the RVs on the different layers.

According to one aspect of the disclosure, a first wireless device configured to communicate first sidelink control information, SCI, and second SCI with a second wireless device is provided. The first wireless device includes processing circuitry configured to: determine a mapping of the second SCI to at least one layer; transmit the first SCI indicating the mapping of the second SCI to the at least one layer; and transmit the second SCI according to the determined mapping.

According to one or more embodiments of this aspect, the determining of the mapping is based at least in part on at least one characteristic associated with wireless communication. According to one or more embodiments of this aspect, the at least one characteristic includes at least one of a rank of a transmission, characteristic included in channel state information, power head room and a reliability requirement. According to one or more embodiments of this aspect, the processing circuitry is further configured to receive a mapping indication indicating a selection of the mapping of the second SCI to at least one layer from a set of available mappings where the determining of the mapping is based at least in part on the received mapping indication.

According to one or more embodiments of this aspect, the mapping of the second SCI to the at least one layer corresponds to code word-to-1 ay er mapping. According to one or more embodiments of this aspect, the codeword-to-1 ay er mapping corresponds mapping of a single codeword to at least one layer. According to one or more embodiments of this aspect, the at least one layer corresponds to a plurality of layers. According to one or more embodiments of this aspect, the codeword-to-1 ay er mapping corresponds to mapping of a plurality of redundancy versions of a codeword to multiple layers. According to one or more embodiments of this aspect, the plurality of redundancy versions of the codeword are transmitted in a same slot.

According to another aspect of the disclosure, a first wireless device configured to communicate with a second wireless device is provided. The first wireless device includes processing circuitry configured to: receive first sidelink control information, SCI, and second SCI; decode the first SCI, the first SCI indicating a mapping of the second SCI to at least one layer; and decode the second SCI based at least in part on the indicated mapping.

According to one or more embodiments of this aspect, the mapping of the second SCI to at least one layer is based at least in part on at least one characteristic associated with wireless communication. According to one or more embodiments of this aspect, the at least one characteristic includes at least one of a rank of a transmission, characteristic included in channel state information, power head room and a reliability requirement. According to one or more embodiments of this aspect, the processing circuitry is further configured to: select a mapping of the second SCI to at least one layer from a set of available mappings; and transmit a mapping indication to the second wireless device indicating the selected mapping. According to one or more embodiments of this aspect, the mapping of the second SCI to the at least one layer corresponds to codeword-to-layer mapping. According to one or more embodiments of this aspect, the codeword-to-layer mapping corresponds mapping of a single codeword to at least one layer. According to one or more embodiments of this aspect, the at least one layer corresponds to a plurality of layers. According to one or more embodiments of this aspect, the codeword-to-layer mapping corresponds to mapping of a plurality of redundancy versions of a codeword to multiple layers. According to one or more embodiments of this aspect, the plurality of redundancy versions of the codeword are transmitted in a same slot.

According to another aspect of the disclosure, a method for a first wireless device for communicating first sidelink control information, SCI, and second SCI with a second wireless device is provided. A mapping of the second SCI to at least one layer is determined. The first SCI indicating the mapping of the second SCI to the at least one layer is transmitted. The second SCI is transmitted according to the determined mapping.

According to one or more embodiments of this aspect, the determining of the mapping is based at least in part on at least one characteristic associated with wireless communication. According to one or more embodiments of this aspect, the at least one characteristic includes at least one of a rank of a transmission, characteristic included in channel state information, power head room and a reliability requirement. According to one or more embodiments of this aspect, receiving a mapping indication indicating a selection of the mapping of the second SCI to at least one layer from a set of available mappings is received. The determining of the mapping is based at least in part on the received mapping indication.

According to one or more embodiments of this aspect, the mapping of the second SCI to the at least one layer corresponds to codeword-to-layer mapping. According to one or more embodiments of this aspect, the codeword-to-layer mapping corresponds mapping of a single codeword to at least one layer. According to one or more embodiments of this aspect, the at least one layer corresponds to a plurality of layers. According to one or more embodiments of this aspect, the codeword-to-layer mapping corresponds to mapping of a plurality of redundancy versions of a codeword to multiple layers. According to one or more embodiments of this aspect, the plurality of redundancy versions of the codeword are transmitted in a same slot.

According to another aspect of the disclosure, a method for a first wireless device for communicating with a second wireless device is provided. First sidelink control information, SCI, and second SCI are received. The first SCI is decoded where the first SCI indicates a mapping of the second SCI to at least one layer. The second SCI is decoded based at least in part on the indicated mapping.

According to one or more embodiments of this aspect, the mapping of the second SCI to at least one layer is based at least in part on at least one characteristic associated with wireless communication. According to one or more embodiments of this aspect, the at least one characteristic includes at least one of a rank of a transmission, characteristic included in channel state information, power head room and a reliability requirement. According to one or more embodiments of this aspect, a mapping of the second SCI to at least one layer is selected from a set of available mappings. A mapping indication is transmitted to the second wireless device indicating the selected mapping.

According to one or more embodiments of this aspect, the mapping of the second SCI to the at least one layer corresponds to codeword-to-layer mapping. According to one or more embodiments of this aspect, the codeword-to-layer mapping corresponds mapping of a single codeword to at least one layer. According to one or more embodiments of this aspect, the at least one layer corresponds to a plurality of layers. According to one or more embodiments of this aspect, the codeword-to-layer mapping corresponds to mapping of a plurality of redundancy versions of a codeword to multiple layers. According to one or more embodiments of this aspect, the plurality of redundancy versions of the codeword are transmitted in a same slot.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present embodiments, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein: FIG. l is a diagram of different redundancy versions read out from a circular buffer of codeword bits;

FIG. 2 is a diagram of different multi-layer transmission schemes;

FIG. 3 is a schematic diagram of an exemplary network architecture illustrating a communication system according to the principles in the present disclosure;

FIG. 4 is a block diagram the wireless devices in the communication system according to some embodiments of the present disclosure;

FIG. 5 is a flowchart of an example process in a transmitting wireless device according to some embodiments of the present disclosure;

FIG. 6 is a flowchart of another example process in a transmitting wireless device according to some embodiments of the present disclosure;

FIG. 7 is a flowchart of an example process in a receiving wireless device according to some embodiments of the present disclosure;

FIG. 8 is a flowchart of another exemplary process in a receiving wireless device according to some embodiments of the present disclosure;

FIG. 9 is CW-to-layer mapping selection at a wireless device according to some embodiments of the disclosure;

FIG. 10 is another CW-to-layer mapping selection at a wireless device according to some embodiments of the disclosure;

FIG. 11 is a diagram of different multi-layer RV mapping schemes according to some embodiments of the disclosure; and

FIG. 12 is a flowchart of a decoding process in a multi-RV transmission according to some embodiments of the disclosure.

DETAILED DESCRIPTION

Before describing in detail exemplary embodiments, it is noted that the embodiments reside primarily in combinations of apparatus components and processing steps related to codeword-to-layer mapping based at least in part on at least one characteristic. Accordingly, components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. Like numbers refer to like elements throughout the description.

As used herein, relational terms, such as “first” and “second,” “top” and “bottom,” and the like, may be used solely to distinguish one entity or element from another entity or element without necessarily requiring or implying any physical or logical relationship or order between such entities or elements. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the concepts described herein. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and/or “including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

In embodiments described herein, the joining term, “in communication with” and the like, may be used to indicate electrical or data communication, which may be accomplished by physical contact, induction, electromagnetic radiation, radio signaling, infrared signaling or optical signaling, for example. One having ordinary skill in the art will appreciate that multiple components may interoperate and modifications and variations are possible of achieving the electrical and data communication.

In some embodiments described herein, the term “coupled,” “connected,” and the like, may be used herein to indicate a connection, although not necessarily directly, and may include wired and/or wireless connections.

The term “network node” used herein can be any kind of network node comprised in a radio network which may further comprise any of base station (BS), radio base station, base transceiver station (BTS), base station controller (BSC), radio network controller (RNC), g Node B (gNB), evolved Node B (eNB or eNodeB), Node B, multi-standard radio (MSR) radio node such as MSR BS, multi-cell/multicast coordination entity (MCE), integrated access and backhaul (IAB) node, relay node, donor node controlling relay, radio access point (AP), transmission points, transmission nodes, Remote Radio Unit (RRU) Remote Radio Head (RRH), a core network node (e.g., mobile management entity (MME), self-organizing network (SON) node, a coordinating node, positioning node, MDT node, etc.), an external node (e.g., 3rd party node, a node external to the current network), nodes in distributed antenna system (DAS), a spectrum access system (SAS) node, an element management system (EMS), etc. The network node may also comprise test equipment. The term “radio node” used herein may be used to also denote a wireless device (WD) such as a wireless device (WD) or a radio network node.

In some embodiments, the non-limiting terms wireless device (WD) or a user equipment (UE) are used interchangeably. The WD herein can be any type of wireless device capable of communicating with a network node or another WD over radio signals, such as wireless device (WD). The WD may also be a radio communication device, target device, device to device (D2D) WD, machine type WD or WD capable of machine to machine communication (M2M), low-cost and/or low-complexity WD, a sensor equipped with WD, Tablet, mobile terminals, smart phone, laptop embedded equipped (LEE), laptop mounted equipment (LME), USB dongles, Customer Premises Equipment (CPE), an Internet of Things (IoT) device, or a Narrowband IoT (NB-IOT) device, etc.

Also, in some embodiments the generic term “radio network node” is used. It can be any kind of a radio network node which may comprise any of base station, radio base station, base transceiver station, base station controller, network controller, RNC, evolved Node B (eNB), Node B, gNB, Multi-cell/multicast Coordination Entity (MCE), IAB node, relay node, access point, radio access point, Remote Radio Unit (RRU) Remote Radio Head (RRH).

An indication generally may explicitly and/or implicitly indicate the information it represents and/or indicates. Implicit indication may for example be based on position and/or resource used for transmission. Explicit indication may for example be based on a parametrization with one or more parameters, and/or one or more index or indices, and/or one or more bit patterns representing the information.

Transmitting in downlink may pertain to transmission from the network or network node to the terminal. Transmitting in uplink may pertain to transmission from the terminal to the network or network node. Transmitting in sidelink may pertain to (direct) transmission from one terminal to another. Uplink, downlink and sidelink (e.g., sidelink transmission and reception) may be considered communication directions. In some variants, uplink and downlink may also be used to described wireless communication between network nodes, e.g. for wireless backhaul and/or relay communication and/or (wireless) network communication for example between base stations or similar network nodes, in particular communication terminating at such. It may be considered that backhaul and/or relay communication and/or network communication is implemented as a form of sidelink or uplink communication or similar thereto.

D2D communication (sidelink communication) may comprise transmission and/or reception of data. It may be considered that D2D communication may generally comprise and/or be defined by data being transmitted from one terminal, e.g. the transmitter or transmitter wireless device, (in particular directly) to another wireless device, e.g., the receiver or receiver wireless device, in particular without the data transmitted being transmitted and/or relayed via a cellular network and/or base station or radio node of such. D2D communication may comprise relaying and/or hopping via a plurality of wireless devices. It may be considered that D2D communication is supported by a network, e.g., by the network and/or base station or radio node providing resource allocation, e.g., allocating resource pools for D2D communication. D2D communication may for example comprise D2D discovery transmission and/or D2D data transmission (the data may in particular be user data and/or payload data). Generally, D2D transmissions may be provided on resources used for UL and/or DL transmissions in cellular communication. However, in some variants, the resources may be UL resources (in the cellular context), e.g., as determined by a standard like LTE, NR, etc.

Note that although terminology from one particular wireless system, such as, for example, 3GPP LTE and/or New Radio (NR), may be used in this disclosure, this should not be seen as limiting the scope of the disclosure to only the aforementioned system. Other wireless systems, including without limitation Wide Band Code Division Multiple Access (WCDMA), Worldwide Interoperability for Microwave Access (WiMax), Ultra Mobile Broadband (UMB) and Global System for Mobile Communications (GSM), may also benefit from exploiting the ideas covered within this disclosure.

Note further, that functions described herein as being performed by a wireless device or a network node may be distributed over a plurality of wireless devices and/or network nodes. In other words, it is contemplated that the functions of the network node and wireless device described herein are not limited to performance by a single physical device and, in fact, can be distributed among several physical devices.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Embodiments provide codeword-to-layer mapping based at least in part on at least one characteristic. Referring again to the drawing figures, in which like elements are referred to by like reference numerals, there is shown in FIG. 3 a schematic diagram of a communication system 10, according to an embodiment, such as a 3GPP-type cellular network that may support standards such as LTE and/or NR (5G), which comprises an access network 12, such as a radio access network, and a core network 14. The access network 12 comprises a plurality of network nodes 16a, 16b, 16c (referred to collectively as network nodes 16), such as NBs, eNBs, gNBs or other types of wireless access points, each defining a corresponding coverage area 18a, 18b, 18c (referred to collectively as coverage areas 18). Each network node 16a, 16b, 16c is connectable to the core network 14 over a wired or wireless connection 20. A first wireless device (WD) 22a located in coverage area 18a is configured to wirelessly connect to, or be paged by, the corresponding network node 16a. A second WD 22b and third WD 22c in coverage area 18b are wirelessly connectable to the corresponding network node 16b, and in some embodiments described herein are in wireless sidelink communication with each other. Further, one or more wireless devices 22 may be in direct communication with each other when not in the coverage area of one or more network nodes 16 or irrespective if the one or more wireless devices 22 are within one or more coverage areas of one or more network nodes 16. Depending on the embodiment, WD 22b may be referred to as a first wireless device 22 while the WD 22c is referred to as a second wireless device, or vice-versa. While a plurality of WDs 22a, 22b (collectively referred to as wireless devices 22) are illustrated in this example, the disclosed embodiments are equally applicable to a situation where a sole WD is in the coverage area or where a sole WD is connecting to the corresponding network node 16. Note that although only two WDs 22 and three network nodes 16 are shown for convenience, the communication system may include many more WDs 22 and network nodes 16.

Also, it is contemplated that a WD 22 can be in simultaneous communication and/or configured to separately communicate with more than one network node 16 and more than one type of network node 16. For example, a WD 22 can have dual connectivity with a network node 16 that supports LTE and the same or a different network node 16 that supports NR. As an example, WD 22 can be in communication with an eNB for LTE/E-UTRAN and a gNB for NR/NG-RAN. Further, it is contemplated that WD 22 can be in direct communication with another WD 22, e.g., sidelink communication, when WD 22 is separately communicating with network node 16 and/or when WD is not separately communicating with network node 16.

A wireless device 22b (also referred to as a transmitting wireless device 22) is configured to include a determination unit 19 which is configured to perform one or more wireless device functions described herein such as with respect to codeword-to- layer mapping based at least in part on at least one characteristic. A wireless device 22c (also referred to as a receiving wireless device 22) is configured to include a de mapping unit 21 which is configured to perform one or more wireless device functions as described herein.

Example implementations, in accordance with an embodiment, of the WDs 22 discussed in the preceding paragraphs will now be described with reference to FIG. 4. The communication system 10 includes the WD 22b already referred to. The WD 22b may have hardware 24 that may include a radio interface 26 configured to set up and maintain a wireless connection with a network node 16 serving a coverage area 18 in which the WD 22b is currently located, and/or another wireless device such as WD 22c via sidelink communications. The radio interface 26 may be formed as or may include, for example, one or more RF transmitters, one or more RF receivers, and/or one or more RF transceivers.

The hardware 24 of the WD 22 further includes processing circuitry 28. The processing circuitry 28 may include a processor 30 and memory 32. In particular, in addition to or instead of a processor, such as a central processing unit, and memory, the processing circuitry 28 may comprise integrated circuitry for processing and/or control, e.g., one or more processors and/or processor cores and/or FPGAs (Field Programmable Gate Array) and/or ASICs (Application Specific Integrated Circuitry) adapted to execute instructions. The processor 30 may be configured to access (e.g., write to and/or read from) memory 32, which may comprise any kind of volatile and/or nonvolatile memory, e.g., cache and/or buffer memory and/or RAM (Random Access Memory) and/or ROM (Read-Only Memory) and/or optical memory and/or EPROM (Erasable Programmable Read-Only Memory).

Thus, the WD 22b may further comprise software 34, which is stored in, for example, memory 32 at the WD 22b, or stored in external memory (e.g., database, storage array, network storage device, etc.) accessible by the WD 22b. The software 34 may be executable by the processing circuitry 28. The software 34 may include a client application 36. The client application 36 may be operable to provide a service to a human or non-human user via the WD 22b. The client application 36 may interact with the user to generate the user data that it provides.

The processing circuitry 28 may be configured to control any of the methods and/or processes described herein and/or to cause such methods, and/or processes to be performed, e.g., by WD 22b. The processor 30 corresponds to one or more processors 30 for performing WD 22b functions described herein. The WD 22b includes memory 32 that is configured to store data, programmatic software code and/or other information described herein. In some embodiments, the software 34 and/or the client application 36 may include instructions that, when executed by the processor 30 and/or processing circuitry 28, causes the processor 30 and/or processing circuitry 28 to perform the processes described herein with respect to WD 22b. For example, the processing circuitry 28 of the wireless device 22 may include a determination unit 19 configured to perform one or more wireless device 22 functions described herein such as with respect to codeword-to-1 ay er mapping based at least in part on at least one characteristic, as described herein.

WD 22c include hardware and software as described above with respect to WD 22b except that WD 22c is configured as a receiving node. For example, the processing circuitry 28 of the wireless device 22 may include a de-mapping unit 21 configured to perform one or more wireless device 22 functions described herein such as with respect to codeword-to-layer mapping based at least in part on at least one characteristic, as described herein.

In some embodiments, the inner workings of the WDs 22 may be as shown in FIG. 4 and independently, the surrounding network topology may be that of FIG. 3.

Although FIGS. 3 and 4 show various “units” such as determination unit 19, and de-mapping unit 21 as being within a respective processor, it is contemplated that these units may be implemented such that a portion of the unit is stored in a corresponding memory within the processing circuitry. In other words, the units may be implemented in hardware or in a combination of hardware and software within the processing circuitry.

FIG. 5 is a flowchart of an example process in a wireless device 22 such as wireless device 22b that acts as a transmitting wireless device 22 according to some embodiments of the disclosure. One or more Blocks and/or functions performed by wireless device 22 may be performed by one or more elements of wireless device 22 such as by determination unit 19 in processing circuitry 28, processor 30, radio interface 26, etc. In one or more embodiments, wireless device 22 such as via one or more of processing circuitry 28, processor 30 and radio interface 26 is configured to determine (Block SI 00) a codeword-to-layer mapping for a second sidelink control information, SCI, codeword (SCI2) based at least in part on at least one characteristic, as described herein. In one or more embodiments, wireless device 22 such as via one or more of processing circuitry 28, processor 30 and radio interface 26 is configured to indicate (Block SI 02) the codeword-to-layer mapping using a first SCI codeword (SCI1), as described herein.

According to one or more embodiments, the radio interface 26 and/or processing circuitry 28 configured is further configured to transmit the first SCI codeword (SCI1) based at least in part on the determined code-word-to-layer mapping. According to one or more embodiments, the at least one characteristic includes at least one of a rank of a transmission, channel state information, power head room and reliability requirements. According to one or more embodiments, the codeword-to-layer mapping corresponds to one of: mapping a single codeword to at least layer, mapping of multiple redundancy versions of a codeword onto multiple layers, mapping of a same codeword onto multiple layers.

FIG. 6 is a flowchart of another example process in a wireless device 22 such as wireless device 22b that acts as a transmitting wireless device 22 according to some embodiments of the disclosure. One or more Blocks and/or functions performed by wireless device 22 may be performed by one or more elements of wireless device 22 such as by determination unit 19 in processing circuitry 28, processor 30, radio interface 26, etc. In one or more embodiments, wireless device 22 such as via one or more of processing circuitry 28, processor 30 and radio interface 26 is configured to determine (Block SI 04) a mapping of the second SCI to at least one layer, as described herein. In one or more embodiments, wireless device 22 such as via one or more of processing circuitry 28, processor 30 and radio interface 26 is configured to transmit (Block SI 06) the first SCI indicating the mapping of the second SCI to the at least one layer, as described herein. In one or more embodiments, wireless device 22 such as via one or more of processing circuitry 28, processor 30 and radio interface 26 is configured to transmit (Block SI 08) the second SCI according to the determined mapping, as described herein.

According to one or more embodiments, the determining of the mapping is based at least in part on at least one characteristic associated with wireless communication. According to one or more embodiments, the at least one characteristic includes at least one of a rank of a transmission, characteristic included in channel state information, power head room and a reliability requirement. According to one or more embodiments, the processing circuitry 28 is further configured to receive a mapping indication indicating a selection of the mapping of the second SCI to at least one layer from a set of available mappings, and where the determining of the mapping is based at least in part on the received mapping indication. According to one or more embodiments, the mapping of the second SCI to the at least one layer corresponds to codeword-to-layer mapping. According to one or more embodiments, the codeword-to-layer mapping corresponds mapping of a single codeword to at least one layer. According to one or more embodiments, the at least one layer corresponds to a plurality of layers. According to one or more embodiments, the codeword-to-layer mapping corresponds to mapping of a plurality of redundancy versions of a codeword to multiple layers. According to one or more embodiments, the plurality of redundancy versions of the codeword are transmitted in a same slot.

FIG. 7 is a flowchart of another example process in a wireless device 22 such as wireless device 22b that acts as a transmitting wireless device 22 according to some embodiments of the disclosure. One or more Blocks and/or functions performed by wireless device 22 may be performed by one or more elements of wireless device 22 such as by de-mapping unit 21 in processing circuitry 28, processor 30, radio interface 26, etc. In one or more embodiments, wireless device 22 such as via one or more of processing circuitry 28, processor 30 and radio interface 26 is configured to receive (Block SI 10) transmission of a first SCI codeword (SCI1), the first SCI codeword being based at least in part on a code-word-to-layer mapping, according to one or more embodiments of the disclosure.

According to one or more embodiments, the radio interface 26 and/or processing circuitry 28 configured is further configured to: determine a codeword-to- layer mapping for second sidelink control information, SCI, codeword (SCI2) that is based at least in part on at least one characteristic, and the codeword-to-layer mapping being indicated using the first SCI codeword (SCI1). According to one or more embodiments, the radio interface 26 and/or processing circuitry 28 configured is further configured to: determine a mapping scheme indicated by the first SCI codeword (SCI1), de-map the second SCI codeword (SCI2), and decode the second SCI codeword (SCI2) based at least in part on the de-mapping. According to one or more embodiments, the at least one characteristic includes at least one of a rank of a transmission, channel state information, power head room and reliability requirements. According to one or more embodiments, the codeword-to-layer mapping corresponds to one of: mapping a single codeword to at least layer, mapping of multiple redundancy versions of a codeword onto multiple layers, mapping of a same codeword onto multiple layers.

FIG. 8 is a flowchart of another example process in a wireless device 22 such as wireless device 22b that acts as a transmitting wireless device 22 according to some embodiments of the disclosure. One or more Blocks and/or functions performed by wireless device 22 may be performed by one or more elements of wireless device 22 such as by de-mapping unit 21 in processing circuitry 28, processor 30, radio interface 26, etc. In one or more embodiments, wireless device 22 such as via one or more of processing circuitry 28, processor 30 and radio interface 26 is configured to receive (Block SI 12) first sidelink control information, SCI, and second SCI, as described herein. In one or more embodiments, wireless device 22 such as via one or more of processing circuitry 28, processor 30 and radio interface 26 is configured to decode (Block SI 14) the first SCI where the first SCI indicates a mapping of the second SCI to at least one layer, as described herein. In one or more embodiments, wireless device 22 such as via one or more of processing circuitry 28, processor 30 and radio interface 26 is configured to decode (Block SI 16) the second SCI based at least in part on the indicated mapping, as described herein.

According to one or more embodiments, the mapping of the second SCI to at least one layer is based at least in part on at least one characteristic associated with wireless communication. According to one or more embodiments, the at least one characteristic includes at least one of a rank of a transmission, characteristic included in channel state information, power head room and a reliability requirement. According to one or more embodiments, the processing circuitry 28 is further configured to: select a mapping of the second SCI to at least one layer from a set of available mappings, and transmit a mapping indication to the second wireless device 22 indicating the selected mapping.

According to one or more embodiments, the mapping of the second SCI to the at least one layer corresponds to codeword-to-layer mapping. According to one or more embodiments, the codeword-to-layer mapping corresponds mapping of a single codeword to at least one layer. According to one or more embodiments, the at least one layer corresponds to a plurality of layers. According to one or more embodiments, the codeword-to-layer mapping corresponds to mapping of a plurality of redundancy versions of a codeword to multiple layers. According to one or more embodiments, the plurality of redundancy versions of the codeword are transmitted in a same slot.

Having generally described arrangements for codeword-to-layer mapping based at least in part on at least one characteristic, details for these arrangements, functions and processes are provided as follows, and which may be implemented by one or more wireless device 22.

Embodiments provide codeword-to-layer mapping based at least in part on at least one characteristic. One or more embodiments of the disclosure described herein are described in relation to 3 GPP NR sidelink. However, these one or more embodiments are equally applicable to any other Radio Access Technologies (RAT) using multi-layer transmission.

According to one or more embodiments, the transmitting wireless device 22 such as for example via one or more of processing circuitry 28, processor 30 and radio interface 26 is configured to adopt (e.g., adapt, select, determine, etc.) the codeword (CW)-to-layer mapping of SCI based at least in part on at least one communication characteristics such as at least one of: the rank of the transmission, channel state information, power head room, reliability requirements etc. The CW-to-layer mapping may refer and/or corresponds to at least one of: mapping of a single CW to one or multiple layers, mapping of multiple redundancy versions (RVs) of a CW onto multiple layers (RV-to-layer mapping), mapping of the same CW onto multiple layers (repetition).

In one or more embodiments, the transmitting wireless device 22 (e.g., WD 22b) such as for example via one or more of processing circuitry 28, processor 30, determination unit 19 and radio interface 26 is configured to select the mapping scheme (e.g., selects the CW-to-layer mapping). An overview of one or more embodiments of an example mapping scheme is illustrated in FIG. 9. The transmitting wireless device 22 such as for example via one or more of processing circuitry 28, determination unit 19, processor 30 and radio interface 26 is configured to determine the suitable mapping based at least in part on available information, e.g., is configured to determine CW-to-layer mapping based on at least one of reliability requirements, available measurements and reports (Block SI 18). In one or more embodiments, the mapping is selected from a predefined set of available mappings. The transmitting wireless device 22 such as for example via one or more of processing circuitry 28, determination unit 19, processor 30 and radio interface 26 is configured to signal (Block SI 20) the selected mapping to the receiving wireless device 22, e.g., through a number of bits in SCI1 carried by PSCCH (details of this example signaling is described below). The transmitting wireless device 22 such as for example via one or more of processing circuitry 28, processor 30, determination unit 19 and radio interface 26 is configured to map the SCI2 symbols according to (e.g., based at least in part on) the selected scheme, e.g., map CW (Block S122).

At the receiving wireless device 22 (e.g., WD 22c), the mapping scheme of SCI2 is determined (Block S124), e.g., by decoding SCI1, such as for example via one or more of processing circuitry 28, de-mapping unit 21, processor 30 and radio interface 26. After de-mapping, SCI2 can be decoded such as for example via one or more of processing circuitry 28, processor 30, de-mapping unit 21 and radio interface 26 (Block s 126).

In one or more embodiments, the receiving wireless device 22 such as for example via one or more of processing circuitry 28, processor 30, de-mapping unit 21, and radio interface 26 is configured to select the mapping scheme and reports the selected mapping scheme to the transmitting wireless device 22, as illustrated in FIG. 10. For example, initially, the receiving wireless device 22 such as for example via one or more of processing circuitry 28, processor 30, de-mapping unit 21 and radio interface 26 is configured to determines the suitable mapping based at least in part on available information such as, for example, one or more characteristics associated with the wireless device 22, e.g., determine mapping scheme based at least on reliability requirements, available measurements, etc. (Block S128). The mapping is chosen from a predefined set of available mappings. Received wireless device 22 then via one or more of processing circuitry 28, processor 30, de-mapping unit 21 and radio interface 26 is configured to signal the selected mapping to the transmitting wireless device 22, e.g., as part of a channel state information report, (Block S130). After receiving the mapping scheme at the transmitting wireless device 22, the transmitting wireless device 22 determines the mapping scheme and performs the transmission of SCI2 with the selected scheme, e.g., maps CW to layers, (Block S132- SI 34). The receiving wireless device 22 can then such as for example via one or more of processing circuitry 28, processor 30 and radio interface 26, de-mapping unit 21 is configured to de-map and decode payload based at least in part on the agreed scheme (Block SI 36).

In one or more embodiments, the adaptive mapping scheme described herein may be disabled and set to a fixed mapping scheme through higher layer signaling. In one or more embodiments, the adaptive mapping scheme described herein may be disabled, and instead the mapping scheme may be made dependent on the number of layers used for PUSCH transmission, e.g., the mapping scheme is based at least in part on the number of layers used for PUSCH. This means that in one or more embodiments the layer mapping used for SCI2 and data transmissions may be the same.

Mapping schemes

Different mapping schemes can be implemented, e.g., depending on whether the coding scheme used for SCI2 supports redundancy versions or not.

According to one or more embodiments, different redundancy versions (RV) of the same SCI codeword (CW) are transmitted on different layers. For example, for 2 -layers transmissions of SCI, RV0 of SCI CW is transmitted on layer 1 and RV1 of the SCI CW is transmitted on layer 2. This allows for improved reliability through spatial diversity gains which may be more critical for the transmission of control information as compared to higher throughput data transmissions. Furthermore, this example may allow for reduced complexity of the decoding by allowing sequential decoding of the RVs on different layers. Meaning, if a receiver wireless device 22 successfully decodes the SCI after decoding a single layer such as for example via one or more of processing circuitry 28, processor 30, de-mapping unit 21 and radio interface 26, it stops performing multilayer processing further.

The RV-to-layer mapping may be done/performed in different ways/processes depending on (e.g., based at least in part on) one or more characteristics associated with at least one of the network, wireless device 22, communication channel configuration, etc. such as one or more of the reliability of the transmission, channel state information, power headroom, etc.: According to one or more embodiments, if reliable channel state information (CSI) is available where the wireless device 22 knows which layer has the best SNR, the wireless device 22 such as for example via one or more of processing circuitry 28, processor 30 and radio interface 26 could “borrow”, e.g., reallocate, power from the other layers on the given resources to use power boosting and single layer transmission, transmitting a single self- decodable RV.

According to one or more embodiments, the wireless device 22 such as for example via one or more of processing circuitry 28, processor 30 and radio interface 26 can transmit different RVs on different layers but prioritize putting the self-decodable RV on the layer which has the highest SNR. This can be combined with power boosting of one of the layers.

According to one or more embodiments, the wireless device 22 such as for example via one or more of processing circuitry 28, processor 30 and radio interface 26 is configured can transmit the same self-decodable RV on all or a subset of layers. This may allow the receiver wireless device 22 (e.g., WD 22c) to apply one or more different combining schemes, e.g., maximum ratio combining (MRC), on the data in one, all, or a subset of layers before decoding. If a subset of layers is used for transmission, power may be borrowed from the other layers to allow for power boosting.

According to one or more embodiments, different RVs can be sent on different layers. The layers used can substitute all, or a subset of the available layers. If a subset of layers is used, power may be borrowed from the other layers to allow for power boosting.

When the coding scheme does not have the notion of RVs, the CW-to-layer mapping could also be done/performed in different ways depending on the reliability of the transmissions, channel state information and power headroom, etc.

According to one or more embodiments, if reliable channel state information (CSI) is available where the wireless device 22 knows which layer has the best SNR, the wireless device 22 could “borrow” power from the other layers on the given resources to use power boosting and single layer transmission, transmitting a single codeword. According to one or more embodiments, the wireless device 22 such as for example via one or more of processing circuitry 28, processor 30, de-mapping unit 21 and radio interface 26 can transmit the same codeword on all, or a subset of layers. This may allow the receiver wireless device 22 (e.g., WD 22c) to apply one or more different combining schemes, e.g., maximum ratio combining (MRC), on the data in one, all, or a subset of layers before decoding. If a subset of the layers is used for transmission, power may be borrowed from the other layers to allow for power boosting.

Configuration and signaling

The CW-to-layer, or RV-to-layer, mapping may be signaled to the receiver wireless devices 22 using the dynamic (e.g., SCI1 or 1 ^st stage SCI) or semi-static (e.g., RRC) control signaling.

According to one or more embodiments, the RV-to-layer mapping is performed using SCI. For instance, a bit map is carried in SCI1 (e.g., 1st stage SCI). Assuming 4 layers, and 4 RVs, 4 triplets of bits are formed, one per layer. Each pair may signal the RV on that layer. Example: Let 111 indicate no RV transmitted. The bitmap [111,000,111,001] would indicate nothing (e.g., no RV) on layer 1 and 3, RV0 on layer 2, and RV1 on layer 4. In another example, a table of allowed RV-to-layer mapping is (pre-)configured and the index to the table is indicated using SCI1.

According to one or more embodiments, a total number of RVs used for transmission of SCI2 can be (pre-)configured. For instance, (pre- )configuration can limit the use of only one RV, e.g., RV0 or two RVs, e.g., RV0 + RV2 etc.

Furthermore, according to one or more embodiments, which RVs to transmit in case of a multi-layer transmission may be selected based at least in part on one or more characteristics such as based at least in part on at least one of: per layer absolute SNR, per layer relative SNR, etc. Alternatively, RVs to transmit in case of multi-layer transmission may be selected based on (pre-)configuration. For instance, different RV-to-layer patterns may be used such as RV0 + RV2+ RV3 + RV1, or RV0 + RV2 + RV0 + RV2, etc. FIGS. 1 l(a)-(d) are diagrams of different multi-layer RV mapping schemes such as (a) single layer transmission with power boosting, (b) single layer mapping;

(c) multi-layer mapping, (d) transmission of RVs on selected layers.

According to one or more embodiments, at the receiver wireless device 22, the decoding process in case of RV-to-layer mapping is described in FIG. 12. According to one or more embodiments, the receiving wireless device 22 such as for example via one or more of processing circuitry 28, processor 30, de-mapping unit 21, and radio interface 26 is configured to determine RV-to-layer mapping based on signaling, as described herein (Block S138). According to one or more embodiments, the receiving wireless device 22 such as for example via one or more of processing circuitry 28, processor 30, de-mapping unit 21, and radio interface 26 is configured to demodulate layer carrying an RV (Block S140). According to one or more embodiments, the receiving wireless device 22 such as for example via one or more of processing circuitry 28, processor 30, de-mapping unit 21, and radio interface 26 is configured to decode using available RVs (Block S142).

According to one or more embodiments, the receiving wireless device 22 such as for example via one or more of processing circuitry 28, processor 30, de-mapping unit 21, and radio interface 26 is configured to determine whether decoding was successful (Block S144). According to one or more embodiments, the receiving wireless device 22 such as for example via one or more of processing circuitry 28, processor 30, de-mapping unit 21, and radio interface 26 is configured to, if decoding is successful, determine reception is successful (Block S146). According to one or more embodiments, the receiving wireless device 22 such as for example via one or more of processing circuitry 28, processor 30, de-mapping unit 21, and radio interface 26 is configured to, if decoding fails or is not successful, determine whether additional RVs are available (Block S148).

According to one or more embodiments, the receiving wireless device 22 such as for example via one or more of processing circuitry 28, processor 30, de-mapping unit 21, and radio interface 26 is configured to, if additional RVs are available, perform Block S140 using another available RV. According to one or more embodiments, the receiving wireless device 22 such as for example via one or more of processing circuitry 28, processor 30, de-mapping unit 21, and radio interface 26 is configured to, if additional RVs are not available, determine reception failed (Block S150).

For CW-to4ayer mapping, the mapping may be signaled to the receiver wireless devices 22 such as for example via one or more of processing circuitry 28, processor 30, de-mapping unit 21 and radio interface 26 is configured to using the dynamic (e.g., SCI1 or 1 ^st stage SCI) or semi-static (e.g., RRC) control signaling.

According to one or more embodiments, the CW-to-layer mapping is performed using SCI, e.g., SCI1. In one example, a bitmap with the same length as the maximum number of layers may be used to indicate which layers are used for transmission. An additional bit may indicate whether the CW is repeated, or if a new longer codeword based on the same data has been created. In one or more embodiments, a table of allowed CW-to-layer mappings is (pre-) configured and the index to the table is signaled using SCI1.

Therefore, one or more embodiments described herein, provide for a wireless device 22 that is configured to adaptively select a codeword-to-layer mapping and also allocate/reallocate power (in one or more embodiments) to the layers based at least in part on at least one characteristics described herein such as at least one of: rank of the transmission, channel state information, power head room, reliability requirements, etc. The signaling aspects of the mapping are also described herein.

Therefore, one or more embodiments, described herein advantageously allow for flexibility in the mapping of the SCI2 codeword onto the different spatial layers being used for PSSCH data. Since the reliability requirements on SCI2 and data may differ, a flexible decoupling of the mapping can help to better adapt the mapping and/or transmission to the channel conditions. In some scenarios, the data channel could benefit from a high rank transmission with lower reliability and with the aid of retransmissions (and soft combining), while SCI2 may need to be correctly decoded in each transmission with high reliability. The layers used for mapping SCI2 can also be updated adaptively as the effective channel gain of the different layers change, e.g., due to mobility.

The reliability may also be achieved through (adaptive) coding, but flexible CW-to-layer mapping can add a layer of flexibility and provide additional means for achieving reliability. Additionally, a reduced implementation complexity can be achieved in some scenarios, where CWs are repeated over layers, or where different RVs are transmitted on different layers. In these scenarios, only a subset of transmitted repetitions/RVs may be needed in the decoding process.

Some Examples

Example A1. A first wireless device (22) configured to communicate with a second wireless device (22), the first wireless device (22) configured to, and/or comprising a radio interface (26) and/or comprising processing circuitry (28) configured to: determine a codeword-to-layer mapping for a second sidelink control information, SCI, codeword (SCI2) based at least in part on at least one characteristic; and indicate the codeword-to-layer mapping using a first SCI codeword (SCI1).

Example A2. The first wireless device (22) of Example Al, wherein the first wireless device (22) and/or radio interface (26) and/or processing circuitry (28) is further configured to: transmit the first SCI codeword (SCI1) that is based at least in part on the determined code-word-to-layer mapping.

Example. A3. The first wireless device (22) of Example Al, wherein the at least one characteristic includes at least one of a rank of a transmission, channel state information, power head room and reliability requirements.

Example A4. The first wireless device (22) of Example Al, wherein the codeword-to-layer mapping corresponds to one of: mapping a single codeword to at least layer, mapping of multiple redundancy versions of a codeword onto multiple layers, mapping of a same codeword onto multiple layers.

Example Bl. A method implemented by a first wireless device (22) configured to communicate with a second wireless device (22), the method comprising: determining a codeword-to-layer mapping for a second sidelink control information, SCI, codeword (SCI2) based at least in part on at least one characteristic; and indicating the codeword-to-layer mapping using a first SCI codeword (SCI1). Example B2. The method of Example Bl, further comprising transmitting the first SCI codeword (SCI1) that is based at least in part on the determined code- word-to-layer mapping.

Example. B3. The method of Example Bl, wherein the at least one characteristic includes at least one of a rank of a transmission, channel state information, power head room and reliability requirements.

Example B4. The method of Example Bl, wherein the codeword-to-layer mapping corresponds to one of: mapping a single codeword to at least layer, mapping of multiple redundancy versions of a codeword onto multiple layers, mapping of a same codeword onto multiple layers.

Example Cl . A first wireless device (22) configured to communicate with a second wireless device (22), the first wireless device (22) configured to, and/or comprising a radio interface (26) and/or comprising processing circuitry (28) configured to: receive transmission of a first SCI codeword (SCI1), the first SCI codeword being based at least in part on a code-word-to-layer mapping.

Example C2. The first wireless device of Example Cl, wherein the first wireless device (22) and/or radio interface (26) and/or processing circuitry (28) is further configured to: determine a codeword-to-layer mapping for a second sidelink control information, SCI, codeword (SCI2) based at least in part on at least one characteristic; and the codeword-to-layer mapping being indicated by the first SCI codeword

(SCI1).

Example C3. The first wireless device (22) of Example C2, wherein the first wireless device (22) and/or radio interface (26) and/or processing circuitry (28) is further configured to: determine a mapping scheme of the second SCI codeword (SCI2); de-map the second SCI codeword (SCI1); and decode the second SCI codeword based at least in part on the de-mapping. Example. C4. The first wireless device (22) of Example Cl, wherein the at least one characteristic includes at least one of a rank of a transmission, channel state information, power head room and reliability requirements.

Example C5. The first wireless device (22) of Example Cl, wherein the codeword-to-layer mapping corresponds to one of: mapping a single codeword to at least layer, mapping of multiple redundancy versions of a codeword onto multiple layers, mapping of a same codeword onto multiple layers.

Example D1. A method implemented by a first wireless device (22) that is configured to communicate with a second wireless device (22), the method comprising: receiving transmission of a first SCI codeword (SCI1), the first SCI codeword being based at least in part on a code-word-to-layer mapping.

Example D2. The method of Example Dl, further comprising: determining a codeword-to-layer mapping for a second sidelink control information, SCI, codeword (SCI2) based at least in part on at least one characteristic; and the codeword-to-layer mapping being indicated by the first SCI codeword

(SCI1).

Example D3. The method of Example D2, further comprising: determining a mapping scheme of the second SCI codeword (SCI2); de-mapping the second SCI codeword (SCI1); and decoding the second SCI codeword based at least in part on the de-mapping.

Example. D4. The method of Example Dl, wherein the at least one characteristic includes at least one of a rank of a transmission, channel state information, power head room and reliability requirements.

Example D5. The method of Example D 1 , wherein the codeword-to-layer mapping corresponds to one of: mapping a single codeword to at least layer, mapping of multiple redundancy versions of a codeword onto multiple layers, mapping of a same codeword onto multiple layers.

As will be appreciated by one of skill in the art, the concepts described herein may be embodied as a method, data processing system, computer program product and/or computer storage media storing an executable computer program. Accordingly, the concepts described herein may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects all generally referred to herein as a “circuit” or “module.” Any process, step, action and/or functionality described herein may be performed by, and/or associated to, a corresponding module, which may be implemented in software and/or firmware and/or hardware. Furthermore, the disclosure may take the form of a computer program product on a tangible computer usable storage medium having computer program code embodied in the medium that can be executed by a computer. Any suitable tangible computer readable medium may be utilized including hard disks, CD-ROMs, electronic storage devices, optical storage devices, or magnetic storage devices.

Some embodiments are described herein with reference to flowchart illustrations and/or block diagrams of methods, systems and computer program products. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer (to thereby create a special purpose computer), special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer readable memory or storage medium that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instruction means which implement the function/act specified in the flowchart and/or block diagram block or blocks.

The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

It is to be understood that the functions/acts noted in the blocks may occur out of the order noted in the operational illustrations. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Although some of the diagrams include arrows on communication paths to show a primary direction of communication, it is to be understood that communication may occur in the opposite direction to the depicted arrows.

Computer program code for carrying out operations of the concepts described herein may be written in an object oriented programming language such as Java® or C++. However, the computer program code for carrying out operations of the disclosure may also be written in conventional procedural programming languages, such as the "C" programming language. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer. In the latter scenario, the remote computer may be connected to the user's computer through a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).

Many different embodiments have been disclosed herein, in connection with the above description and the drawings. It will be understood that it would be unduly repetitious and obfuscating to literally describe and illustrate every combination and subcombination of these embodiments. Accordingly, all embodiments can be combined in any way and/or combination, and the present specification, including the drawings, shall be construed to constitute a complete written description of all combinations and subcombinations of the embodiments described herein, and of the manner and process of making and using them, and shall support claims to any such combination or subcombination.

It will be appreciated by persons skilled in the art that the embodiments described herein are not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings without departing from the scope of the following claims.