Patent ID: 12192974

DETAILED DESCRIPTION OF THE INVENTION

In the following, embodiments of the present invention are described in further detail with reference to the enclosed drawings in which elements having the same or a similar function are referenced by the same or similar reference signs.

Also, in the following, reference is made to OFDM (orthogonal frequency division multiple access) networks and/or LTE (long term evolution) networks, embodiments described herein are not limited hereto.

Although, the embodiments described herein may relate to Log Term Evolution (LTE) any other communication scheme, in particular in connection with slotted communication using slots may be used. A slot may be regarded as an interval, e.g., in time and/or frequency that is possibly sub-structured, e.g., into symbols or the like, and provides for some kind of synchronization for communication, wherein synchronization is not limited to time.

FIG.1is a schematic representation of an example of such a network infrastructure, like a wireless communications system including a plurality of base stations eNB1to eNB5, each serving a specific area surrounding the base station schematically represented by the respective cells1001to1005. The base stations are provided to serve users within a cell. A user may be a stationary device or a mobile device. Further, the wireless communication system may be accessed by IoT devices which connect to a base station or to a user.FIG.1shows an exemplary view of only five cells, however, the wireless communication system may include more or less of such cells.FIG.1shows two users UE1and UE2, also referred to as user equipment (UE), that are in cell1002and that are served by base station eNB2. Another user UE3is shown in cell1004which is served by base station eNB4. The arrows1002,1022and1023schematically represent uplink/downlink connections for transmitting data from a user UE1, UE2and UE3to the base stations eNB2, eNB4or for transmitting data from the base stations eNB2, eNB4to the users UE1, UE2, UE3. Further,FIG.1shows two IoT devices1041and1042in cell1004, which may be stationary or mobile devices. The IoT device1041accesses the wireless communication system via the base station eNB4to receive and transmit data as schematically represented by arrow1051. The IoT device1042accesses the wireless communication system via the user UEs as is schematically represented by arrow1052. UE1, UE2and UEs may access the wireless communications system or network by communicating with the base station.

The wireless communications network system may be any single-tone or multicarrier system based on frequency-division multiplexing, like the orthogonal frequency-division multiplexing (OFDM) system, the orthogonal frequency-division multiple access (OFDMA) system defined by the LTE standard, or any other IFFT-based signal with or without CP, e.g. DFT-SOFDM. Other waveforms, like non-orthogonal waveforms for multiple access, e.g. filterbank multicarrier (FBMC), may be used. Other multiplexing schemes like time-division multiplexing (time-division duplex—TDD) may be used.

An OFDMA system for data transmission may include an OFDMA-based physical resource grid which comprises plurality of physical resource blocks (PRBs) each defined by 12 subcarriers by 7 OFDM symbols and including a set of resource elements to which various physical channels and physical signals are mapped. A resource element is made up of one symbol in the time domain and one subcarrier in the frequency domain. For example, in accordance with the LTE standard a system bandwidth of 1.4 MHz includes 6 PRBs, and the 200 kHz bandwidth in accordance with the NB-IOT enhancement of the LTE Rel. 13 standard includes 1 PRB. In accordance with LTE and NB-IOT, the physical channels may include the physical downlink shared channel (PDSCH) including user specific data, also referred to as downlink payload data, the physical broadcast channel (PBCH) including for example the master information block (MIB) or the system information block (SIB), the physical downlink control channel (PDCCH) including for example the downlink control information (DCI), etc. The physical signals may comprise reference signals (RS), synchronization signals and the like. The LTE resource grid comprises a 10 ms frame in the time domain having a certain bandwidth in the frequency domain, e.g. 1.4 MHz. The frame has 10 subframes of 1 ms length, and each subframe includes two slots of 6 or 7 OFDM symbols depending on the cyclic prefix (CP) length.

FIG.2ashows an exemplary scheme of an LTE frame88as described in connection withFIG.1, the frame88may have ten subframes of 10 ms length, wherein each subframe may include two slots89of six or seven OFDM symbols each, depending on the cyclic prefix (CP) length. For example, in LTE, each slot89may comprise a number of resource blocks92, wherein each resource block92may be divided into a number of, for example, 12 subcarriers in frequency and into six or seven symbols in time. Resource elements94of resource block92may have a length of one symbol and may occupy one subcarrier.

To transmit information, one, a plurality or all resources elements94of a resource block92may be utilized. Alternatively or in addition, more than one resource block92(all available resource elements therein or only a part thereof) may be used.

FIG.2bshows a schematic view of an alternative structure of frame88. Frame88may have a number of L slots89, wherein L may be any suitable number larger than 0, e.g., 1 or more, 2 or more, 5 or more, 10 or more or 15 or more such as 18. In accordance withFIG.2a, each slot89may comprise a number of symbols, wherein the number of symbols may be different to 6 or 7, e.g., 14 or any other number.

FIG.3shows an exemplary LTE OFDMA-based subframe with two antenna ports for different selected Tx antenna ports. The subframe includes two resource blocks (RB) each made up of one slot of the subframe and 12 subcarriers in the frequency domain. The subcarriers in the frequency domain are shown as subcarrier 0 to subcarrier 11, and in the time domain, each slot includes 7 OFDM symbols, e.g. in the slot 0 OFDM symbols 0 to 6 and in slot 1 OFDM symbols 7 to 13 so as to have 14 OFDM symbols in a subframe. The white boxes106represent resource elements allocated to the PDSCH including the payload or user data, also referred to a payload region. The resource elements for the physical control channels (including non-payload or non-user data), also referred to the control region, are represented by the hatched boxes103. In accordance with examples, resource elements103may be allocated to the PDCCH, to the physical control format indicator channel (PCFICH), and to the physical hybrid ARQ indicator channel (PHICH). The cross-hatched boxes107represent resource elements which are allocated to the RS that may be used for the channel estimation. The black boxes108represent unused resources in the current antenna port that may correspond to RSs in another antenna port. The resource elements103,107,108allocated to the physical control channels and to the physical reference signals are not evenly distributed over time. More specifically, in slot 0 of the subframe the resource elements associated with the symbol 0 and the symbol 1 are allocated to the physical control channels or to the physical reference signals, no resource elements in the symbols 0 and 1 are allocated to payload data. The resource elements associated with symbol 4 in slot 0 as well as the resource elements associated with symbols 7 and 11 in slot 1 of the subframe are allocated in part to the physical control channels or to the physical reference signals. The white resource elements shown inFIG.3may include symbols associated with payload data or user data and in the slot 0 for symbols 2, 3, 5 and 6, all resource elements106may be allocated to payload data, while less resource elements106are allocated to payload data in symbol 4 of slot 0, and no resource element is allocated to payload data in symbols 0 and 1. In slot 1, the resource elements associated with symbols 8, 9, 10, 12 and 13 are all allocated to payload data, while for symbols 7 and 11 less resource elements are allocated to payload data.

Reference to LTE, especially in view of a frame structure, is made by way of non-limited example only. Frames may comprise a different structure, especially in view of a number of subframes, slots and/or resource blocks.

FIG.4shows a schematic block diagram of a wireless communications network40according to an embodiment. The wireless communications network40comprises one, two, three or even a higher number of transmitters121,122respectively. The transmitters12may comprise, for example, a functionality of IoT devices104and/or of a UE.

The wireless communications network40comprises a base station14configured for operating a wireless communications network cell100of the wireless communications network40so as to provide communication in the cell100. The communication may relate to a direct communication between the transmitters121and122and/or to a communication between the transmitter121and the base station14and/or between the transmitter122and the base station14. For example, the base station14may set up a communication scheme as described in connection withFIGS.1to3as a basis for the embodiments described herein. I.e., the communication may be performed such that a communication frame is divided into a plurality of slots. Each slot comprises a plurality of associated physical resources as described in connection withFIG.2.

The transmitters121and122may be configured for transmitting a signal161,162, respectively. The respective frame881,882utilized, filled or referenced at the respective transmitter121,122respectively may be a same frame structure at the base station14, i.e., may correspond to a synchronization in time, frequency, and/or space at the base station14. Based on several mechanisms such as imprecise clocks of the transmitters121and122, the frames881and882may have an offset in time when the signals161and162arrive at the base station14. Further, based on different traveling times (Time Of Flight) of the signals161and162, mechanisms like timing advance may be applied so as to synchronize frames881and882at the base station14. I.e., the transmitters121and122may transmit at different times so as to compensate for the different time of flights.

The set-individual offset with regard to the synchronization in time, space and/or frequency at the base station14does not limit the signals to be transmitted to be directed to the base station each but also allow, alternatively or in addition a peer-to-peer communication, i.e., a transmission of signals directly between peers such as UEs or IoT devices. A peer-to-peer communication may benefit from the same advantages and may never the less agree on a common time/frequency/space structure as the one implemented at the base station14.

In difference to those concepts or effects and in difference to a constant offset in time for a specific transmission, the transmitter121and/or122is configured to offset the transmission of each utilized slot within a frame individually, i.e., so as to comprise a set-individual offset as described in connection withFIG.5. The set-individual offset refers to a set of physical resources used or employed within a slot. Resources of a frame or slot may exclusively be allocated to a single node. Alternatively, the base station may be configured for operating the wireless communications network cell according to a sparse allocation scheme. Alternatively or in addition, the transmitter may be configured for using the slots according to a sparse allocation scheme. A sparse allocation scheme may be understood as allocating only a subset of all possible resources to a node or application.

An example for a sparse allocation scheme is a non-orthogonal multiple access (NOMA) scheme. Such a NOMA scheme may be understood as allocating only a subset of slots to a transmitter or application and to reuse resources amongst transmitters or applications so as to generate an overload within the network. Collisions obtained thereby may be resolved such that an overall throughput may be increased. For example,FIG.5illustrates the frame88as having a number of N slots891to89N, each slot891to89Nhaving a time duration TSwithin the frame duration TF. For example, a layer181comprises resources of slots891and893. A layer182may comprise slots892and894. A slot183may comprise slots891and894. By way of example, the four slots891to894are associated or divided into three sets or layers of slots, wherein each slot is double-used by a user181to183. A different way of allocating or dividing resources may be implemented.

To each slot89, there may be associated a set22of resources that may implement at least one resource element94, a set or even complete resource block respectively. The set22of resources used by a transmitter may be set-individually offset with respect to a beginning or start241,242,243,244, respectively of a slot89i. The transmitter may send the signal161such that the resources2211are offset by the offset O11with respect to the beginning241of slot891. Further, the transmitter may be configured for transmitting the signal161such that the set2213of resources is offset by an offset O12with respect to the start243of slot893in time. Offsets O11and O12are different from each other and are individually selected or determined for each set2211and2213within a layer181to183.

In layer182, set2221of resources is offset by an offset O21with respect to the start242of slot892. Further, the set2222is offset by an offset O22with respect to the start244of slot894.

Further, in layer183, a set2231(that may be equal to the set2211) may be offset with a set-individual offset O31with respect to the start241. The set2232of layer183, that may be equal to the set2222, may be offset by an offset O32with respect to the start244.

Within one layer181to183and/or within sets22of a same slot89, the offsets may differ from each other, wherein, the offsets are selected, chosen or set such that the respective offset applies at the receiving node, e.g., the base station. This allows colliding sets, e.g., sets2211and2231, to be at least partially successfully decoded with a high probability.

A transmitter may use, select or have allocated any number of slots and/or any number of sets22and/or any number of resources allocated to a slot or OFDM symbol.

In other words, embodiments provide for a system where users access multiple instances of the channel resource for transmission. The motivation for the sparse resource mapping is to reduce the receiver complexity while effectively allowing for overloading the system. Embodiments provide for a system that extends known systems to consider (probably deterministic) sparse slot allocation, i.e., the transmission is spread over a subset of available slots within one frame (or subsets of physical resource blocks—PRBs—within an orthogonal grid). Additionally, embodiments allow to employ a user specific shift/offset in time and/or frequency domain, wherein user specific is related to user-specific patterns of set-individual offsets within one layer.

Embodiments are based on the assumptions that a sparse resource allocation can be assumed randomly, i.e., each user may pick a random slot/PRB(s) for transmission, as in a contention-based scenario. Alternatively, the allocation may be scheduled following a certain structure which can be regular (e.g., structured based on a predefined code-book or generated following a certain rule or may, alternatively, be irregular). Alternatively, or in addition, a UE/device or a set of UEs/devices with sporadic activation can use a preconfigured (rather than scheduled) set of resources such as a resource pool/bandwidth part or the like for non-orthogonal transmissions in a grant-free fashion. The preconfigured set of resources can be understood as a form of semi-persistent scheduling. A further assumption is that each slot may carry a replica of the user's code-word (e.g., in a random-access scheme) and/or may have parts of the message to be transmitted (i.e., the message is split and transmitted over multiple slots in case of a large code-word and/or a low code-rate).

FIG.6ashows a schematic diagram for illustrating an implementation of set-specific offsets according to an embodiment. By way of example, there is shown a two-dimensional grid of resources R1and R2, wherein, for example, those resources are selected from the resource frequency, time, and space.

By way of example, resource R1may be time and resource R2may be frequency. Sets221and222of resources that are used by a receiver may be located differently in time and/or frequency, but may also have one resource with same, similar, or identical value. For example, as described in connection withFIG.5, the sets221and222may have a same frequency at different times or different frequencies and the same times. Sets221and222are offset by set-individual offsets O1and O2in time.

FIG.6bshows a schematic diagram of sets221and222being offset by set-individual offsets O1, O2, respectively in frequency, i.e., resource R2.

FIG.6cshows a schematic diagram of the sets221and222being offset as well as in resource R1(time) and resource R2(frequency). E.g., set221is offset with an offset O11in time and with an offset O12in frequency with respect to a start242in time and of a minimum frequency261of the resources according to a synchronized schedule of the frame88.

Set222may be offset with an offset O21with respect to a start244in time and/or with an offset O22with respect to a minimum frequency262of the resources in the synchronized frame88, wherein synchronization refers, within the scope of the present embodiments, to time and frequency.

Offsets described herein relate to non-zero values in time and/or frequency. According to an embodiment, it may be sufficient that one offset, i.e., the time-value or the frequency-value is non-zero. According to embodiments, both values may be non-zero. Further, embodiments relate to transmitters that offset different sets within a single frame with offsets of different resources. I.e., a first set of resources within a frame of a transmitter may be offset with respect to time and a second set may be offset with respect to frequency only. Alternatively, at least one of the sets may be offset in two-dimensions or even in three-dimensions, i.e., a third resource.

When referring again toFIG.5, a maximum value of the set-individual offset in the illustrated two-dimensional grid, e.g., a time-frequency grid, may be selected such that a center of gravity of the used set of resources is located within the synchronized slot of the frame. I.e., a set-individual offset may comprise a time offset being larger than −0.5 of a time duration the slot and smaller than +0.5 of the time duration. Between those values, the set-individual offset may have any value, wherein, for example, the offsets may differ with respect to each other by at least 0.05 of the time duration of the slot, at least 0.1 of the time duration of the slot or 0.15 of the slot duration. Alternatively, although the described offset in time provides for the advantage that the transmitted part signal may uniquely associated with a slot, embodiments are not limited hereto such that an offset in time of less than −0.5 of the time duration and/or more than +0.5 of the time duration may be selected.

Alternatively or in addition, the set-individual offset may comprise a frequency offset. The frequency offset may be larger than −0.5 of a frequency bandwidth of a carrier or subcarrier used by the set and may be smaller than +0.5 of the frequency bandwidth. I.e., the set22being arranged within a carrier or subcarrier, the frequency offset may be smaller than half of the bandwidth in positive or in negative direction. Alternatively, although the described offset in frequency provides for the advantage that the transmitted part signal may uniquely associated, embodiments are not limited hereto such that an offset in frequency of less than −0.5 of the bandwidth and/or more than +0.5 of the bandwidth may be selected.

FIG.6dshows a comparison between different offset schedules. Different layers18imay access or use different slots of frame88, e.g. according to a sparse allocation scheme such as non-orthogonal multiple access (NOMA). Alternatively, a different scheme may be implemented and/or all slots may be accessed or used by one or more layers.

By way of example, the different schemes to be compared inFIG.6dare illustrated over a common time axis t of time duration tFrameof frame89, wherein the details explained may be transferred to any other resource being equipped with an offset such as frequency. The time axis may be valid for the base station, i.e., shows the arrival of signals at the base station.

The upper portion ofFIG.6dshows a synchronized or non-staggered or offset-free communication using the communication scheme or frame structure ofFIG.2b. Offset free refers, as the set-individual offset, to a synchronization at the base station, i.e., the signals of the transmitters arriving at the base station may be, for example, free of an offset, e.g., using a timing advance or the like.

The centered portion ofFIG.6dshows a known regular staggered communication in which each layer18has a constant, i.e., layer-specific offset such that a transmitter using layer182uses offset Δ1for all slots and a transmitter using layer183uses a different offset Δ1for all slots.

The lower portion ofFIG.6dshows a concept in accordance with embodiments. The concept may be referred to as irregular staggered which does not exclude that set-specific offsets for a regular or irregular pattern within a frame but refers to differing offset values within a layer18. For example, in layer181a set-specific offset O11, is implemented for the first set2211of physical resources used in slot891and set-specific offset O12is implement for the second set2212of physical resources used in slot893. Offsets O11and O12may differ from each other. Similarly, in layer182a set-specific offset O21, is implemented for the first used set2221of physical resources used in slot892and set-specific offset O22is implement for the second used set2222of physical resources used in slot89L. Similarly, in layer183a set-specific offset O31, is implemented for the first used set2231of physical resources used in slot893and set-specific offset O32is implement for the second used set2232of physical resources used in slot89L.

The set-individual offset O12may be comparatively large but is selected such that a center of gravity3812of the set2212is still within the associated or dedicated slot893. Accordingly, centers of gravity of the other sets may be inside the associated slots. The center of gravity of a slot such as center of gravity3812may be determined by a center of time or half of the time duration and/or by a center of frequency or half of the used frequency bandwidth.

Whilst offset values of different layers may be same or equal, even for a same slot used in different layers, set-specific offset values within a same layer18imay differ from each other with regard to at least one resource or dimension of the grid. That is, by way of example, when implementing a set-specific offset in two dimensions such as time and frequency, differing in time, set-specific offsets may be same or equal in frequency and/or vice versa.

FIG.7ashows a schematic block diagram of the wireless communications network cell100in a configuration having the base station14receiving signals from nine transmitting UEs121to129.

FIG.7bshows a schematic diagram of an example scheme for scheduling the six OFDMA symbols to the nine UEs121to129ofFIG.7aso as to overload the wireless channel and to enable the nine transmitters to transmit simultaneously. Although this overload may lead to interference, based on a pattern according to which the different symbols are accessed, successful decoding may be possible. Alternatively or in addition to the number of symbols, the frame may be divided differently. An overloading allocation28this allocates only specific symbols or allocated sets32of resources to respective layers181to189.

To each transmitter121to129, a respective layer181to189may be associated. As described, more than one layer may be associated to a transmitter. The layers18associated to a single transmitter may be cyclically shifted so as to allow a single transmitter using resources that are spaced within the respective resources so as to increase an overall communication quality. For example, if a specific time slot or frequency range is blocked, probability may be low or reduced for a spaced apart time or frequency.

An overloading allocation34with offsets allows to obtain an offset to each allocated set321to3218over all layers181to189. The offset may be different between sets32within a layer181to189.

In other words, one aspect of the embodiments described herein is that each user/layer has a random or deterministic offset, i.e., time delay or frequency shift or space shift in the range of at most ±half the respective maximum values such as a slot-duration or frequency bandwidth for each transmission, in particular, sparse transmissions. Each user/layer may transmit on more than one slot within one frame, for example, in a regular sparse scheme. Each of these transmissions may have a certain time shift and/or frequency shift on top. If shifts/delays are selected in the range of ±half the slot duration, the system may be denoted as “frame asynchronous”, i.e., parts of the message may exceed the frame-boundaries, e.g., when the first slot has a negative time-offset and/or the last slot has a positive time-offset. If shifts are selected such that all transmissions area allocated within the frame, the system may be denoted as frame-synchronous. This may be obtained, for example, when leaving the first and/or last slot unused, e.g., in a sparse transmission, when providing for a positive offset for the first slot and/or a negative offset for the last slot. Although this was described in connection with time, the slots can also be frequency bins or any other resource.

When referring again toFIG.7a, the delay to be applied may be determined by a network controller being in communication with the base station. Such a network controller may be at least partially implemented at a distant entity in communication with the base station and/or may at least partially be implemented as part of the base station. The network controller may at least partially be implemented in one or more transmitters.

The network controller36may be configured for determining an upper bound and/or a lower bound of the set-individual offset. Such information may be broadcasted, for example, by the network controller36and/or the base station14. The transmitters121and129may select their respective offset to be applied within the boundaries communicated by the network controller36and/or the base station14. That is, according to an embodiment, the transmitter selects its offset within the boundaries. Alternatively or in addition, the network controller may be configured for determining the set-individual offset. The network controller may thus provide for a direct value, a range from which the set-specific offset is to be selected and/or a codebook containing a plurality of offset-values, e.g., to determine a sequence of offset-values for a plurality of slots or frames such that by using such a sequence additional information or redundancy may be transmitted. The sequence may be determined or selected, for example, so as to obtain any kind of pseudo-random sequence being influenced, for example by a user-ID, a type of the device, a type of application operated by the transmitter or the like. Such a sequence may be preconfigured by way of a codebook.

The offset may be determined for a single transmitter, for all transmitters and/or group-wise for a group of transmitters. For example, transmitters that are collocated with respect to each other, for example, transmitters121to123, transmitters124to126and transmitters127to129, may be controlled so as to implement a same or at least comparable set-individual offset.

Such a group-based selection of the set-specific offset or a sequence thereof may be done based, for example, on a device category such that devices of a same category may have same offset-values or same boundaries, wherein different boundaries of different types of devices may be connected/overlapping or disjoint. Example types of devices are Internet-of-Things (IOT), voice, URLLC, eMBB (enhanced Mobile Broadband), etc., wherein this does not exclude a finer granularity, e.g., within IoT devices, for example, devices relating to water, gas, power etc. Alternatively or in addition, such a group based selection may also refer to an application being executed or implemented at the transmitter. This allows to facilitate autonomous networks excluding a centralized base station. Further, groups may also relate to types of services, e.g., voice services, IoT services, gold services or the like. For some or each of such services a specific offset or range thereof may be defined.

The base station14may transmit a signal to the transmitters121to129, for example, as a signal having a dedicated receiver and/or by use of a broadcast signal. The signal may indicate the determined set-individual offset. The transmitter121to129may apply the set-individual offset according to the received signal. That is, alternatively or in addition to setting only the boundaries of the specific set-individual offset, the set-individual offset may be determined completely by the network controller36. Alternatively or in addition, the transmitter121to129may select the set-individual offset randomly.

According to an embodiment, the base station14may operate the wireless communications network cell100according to a specific communication mode or in one of a predefined communication mode. A first mode may be, for example, to allocate all slots to a transmitter. a second mode may be, for example, to have a first overload rate such as 3:2. A third mode may be implemented so as to implement a second overload rate such as 9:6 as indicated inFIG.7bor a different rate. The base station14may implement only one of those modes or may be configured to switch between modes, for example, responsive to a number of transmitters requesting communication within the cell100. In either way, the transmitters may have knowledge about a specific number of sets22that may be used for communication within a frame. The transmitters12may further have knowledge about pre-defined patters of set-individual offsets, for example, by receiving a respective signal from the network controller36over the base station14. Alternatively, such information may be common for the whole network and thus known to the transmitter. The transmitter121to129may select one of the patterns set-individual offset and may implement the set-individual offset according to the selected pattern.

By way of example, the network controller36may be configured for determining a plurality of sets of offsets. Each set of offsets may contain a plurality of offset-values associated to a plurality of sets22of physical resources. The transmitter may be configured for selecting one of the plurality of sets of offsets and to apply the set-individual offset to a plurality of sets22of physical resources within a frame.

According to an embodiment, each of the sets of offset-values may comprise a unique offset-pattern associated to the set of offset values. Such a uniqueness may also be known to the base station14and may thus enhance decoding or resolving interference as, for example, detected offsets for a subset of used sets22may lead to a pre-known or at least decodable set-individual offset for one or more remaining sets.

FIG.8ashows a schematic block diagram illustrating the concept of mapping or dividing the signal16to be transmitted by a transmitter12into a number of part signals421to42P, wherein P may be any number larger than 1, for example, 2, 3, 4, 5, or even a larger number, e.g., 10, 15 or higher. The content of the signal16may be split so as to be included into one or more part signals421to42P. For example, the content of the signal16may be coded with a code rate such that information that needs to be transmitted is increased. When exceeding a number of OFDM symbols within a slot, a higher number of slots may be used so as to commonly transmit the signal16. Alternatively or in addition, one or more of the part signals421to42Pmay contain a retransmission of a different part signal. I.e., the content of any part signal421to42Pmay be same and/or different when compared to each of the remaining part signals. Each of the part signals421to42Pmay be mapped to a respective set221to22Pof frame88. That is, the transmitter may be configured for dividing the signal16into a number of part signal and/or to retransmit at least a part of the signal as a part signal.

The number of part signals42may be known at the beginning of mapping the signal16into part signals, e.g., based on the number of fractions used or that may be used. Alternatively, the number may dynamically be chosen, e.g., when awaiting a positive or negative acknowledgement (ACK/NACK) that may cause the transmitter to transmit a further retransmission as part of the signal, thereby spontaneous or dynamically increasing the number of part signals. That is, the number of re-transmissions can be fixed or adaptive, e.g. each UE re-transmits until an ACK is received of a maximum number of re-transmissions is performed. Embodiments relate to the set-individual offset being implemented as a pattern. For example, each part of the message (part signal) is derived from the number of repetitions may indicate its number of retransmissions by the offset chosen. (e.g. the first transmission has 0 offset, the second has 1, the third has 2 . . . etc.). This has the advantage that a receiver can estimate the number of re-transmissions that may be used for successful decoding.

I.e., a part signal may be at least a first re-transmission of another part signal, wherein the set-individual offset is selected such that the set-individual offset applied to the re-transmitting part-signal is associated with a number of prior transmissions.

FIG.8bshows a further schematic block diagram illustrating the concept of mapping the signal16to be transmitted by a transmitter12into a number of part signals42. According to an option A) the signal16may be transmitted in one single slot89iof frame88, i.e., the signal16may be incorporated into a single part signal421. This part signal421may be repeatedly transmitted in the associated slots which are, for example, all slots89of frame88. That is, the part signal421is transmitted as part signal421,1in the first allocated or selected slot891, as part signal421,2in the second slot892, as part signal421,3in the third slot893and so on. The part signals421,iwith i=1, . . . , I may thus contain equal information or be equal.

According to an option B), the signal16is divided into a number of I part signals42iwith i=1, . . . , I and be each a fraction of signal16and thus comprise different information. Each of the part signals42imay be transmitted in a corresponding slot89i.

Option A) and B) are extreme cases in either having no retransmission and only fractions in option B) or only retransmissions and no fractions in option A). Embodiments are not limited hereto but allow for mixing both options up, i.e., to have fractions as well as repetitions/retransmissions. Further embodiments are not limited to transmissions in which each slot is assigned to a user but can also be implemented in sparse allocation schemes.

Embodiments allow thus to an improved diversity that can be exploded at the receiver for decoding. Embodiments may be used for an extension to NOMA with sparse resource allocation in order to increase the time-diversity and to resolve collisions, but are not limited hereto and may also be implemented in connection with regular resource allocations. Embodiments may alternatively or in addition be used as an extension, i.e., on top, to time-hoping concepts. Such a design is proposed for ultra-reliable low latency communication (URLLC), see [2]. In connection with the embodiments described herein, a low latency may be obtained together with a high probability of decoding messages at the receiver such that both targets may be achieved, i.e., having a high throughput and having a high reliability. An example for a known URLLC given in [2], where K repetitions are scheduled persistently to the UE in order to increase the reliability states that: “even more than one UE is assigned the same periodicity, offset and symbol allocation with the slot, and if these UEs become active at the same time, then they will collide persistently. Frequency hopping can address this situation to some extent provided there are sufficiently many RBs available to hop across relative to the RB allocation needed for each UE. However, especially if reliability is an important consideration (such as for eURLLC), the number of RBs that may be used for each transmission may itself be large. In such a scenario, an alternative option is to have hopping in the time domain. The same design is applicable to both PUSCH repetition with and without grant.”

Embodiments are related to a sign and additional user dependent fractional offset to the repetitions (on resource element (RE)-level in time/frequency domain) in order to provide persistent collision.

A transmitter according to an embodiment, for example, the transmitter121and/or122ofFIG.4and/or one or more of the transmitters121to129ofFIG.7amay comprise an interface configured for transmitting a signal in a wireless communications network cell of a wireless communications network. The transmitter may comprise a control unit configured for mapping the signal into a number of part signals, as described, for example, in connection withFIG.8a. The control unit may be configured for transmitting the number of part signals with a corresponding number of associated slots or sets22of the wireless communications network cell using a corresponding number of sets of physical resources. Each set may contain at least a subset of the associated plurality of physical resources of the slot. The control unit may be configured for transmitting the number of part signals with a set-individual offset such that each set of physical resources is shifted with respect to a synchronized start of the slot in time and/or frequency. That is, the part signals may be transmitted in a set22each, wherein each set may have a subset or all of the available resources of a slot.

A base station according to an embodiment, for example, the base station14, may be configured for operating a wireless communications network cell, e.g., cell100, according to a wireless communications network scheme. The scheme may comprise a plurality of frames, each frame comprising a plurality of slots, each slot comprising a plurality of associated physical resources. The base station may comprise an interface configured for receiving a first number of part signals from a first transmitter. The interface may be configured for receiving a second number of part signals from a second transmitter. Each part signal is associated to a slot of a dedicated frame, i.e., the first number of part signals and the second number of part signals are received within the same frame and are scheduled, by the respective transmitter, to the same frame. Each part signal of the first number of part signals comprises a set-individual offset within the first number and with respect to a synchronized start of the slot. Each part signal of the second number of part signals comprises a set-individual offset within the second number and with respect to the synchronized start of the slot. According to embodiments, the set-individual offsets of the first number and of the second number may be same, for example, based on a group-wise definition of a network controller and/or by selecting the same values by the respective transmitter. Alternatively, the offsets may be different when compared to each other. In both cases, the set-individual offsets may comprise different offset values within the first number and within the second number of parked signals. the base station may comprise a decoding unit configured for decoding the received first part signals and the received second part signals and for correcting interference caused by an overlap of the first part signals with the second part signals.

In the following, additional embodiments and aspects of the invention will be described which can be used individually or in combination with any of the features and functionalities described herein.1. Wireless communications network comprising:a base station configured for operating a wireless communications network cell of the wireless communications network so as to provide communication in a plurality of slots89, each slot89comprising a plurality of associated physical resources;at least one transmitter12configured for transmitting a signal16in the wireless communications network cell100by mapping the signal16into a number of part signals42and for transmitting the number of part signals42with a corresponding number of associated slots89using a corresponding number of sets22of physical resources, each set22containing at least a subset of the associated plurality of physical resources of the slot89;wherein each set22of physical resources is received at the base station14shifted with a set-individual offset O with respect to a synchronized start24,26of the slot89.2. The wireless communications network of aspect 1, wherein the set-individual offset O comprises an offset in time and/or in frequency.3. The wireless communications network of aspect 1 or 2, wherein the set-individual offset O is set such that in a two-dimensional time-frequency grid a center of gravity of the set22of resources is within the associated slot89.4. The wireless communications network of one of previous aspects, wherein the set-individual offset O comprises a time offset and wherein the time offset is larger than −0.5 of a time duration of the slot89and smaller than +0.5 of the time duration.5. The wireless communications network of one of previous aspects, wherein the set-individual offset O comprises a frequency offset and wherein the frequency offset is larger than −0.5 of a frequency bandwidth of a carrier and smaller than +0.5 of the frequency bandwidth.6. The wireless communications network of one of previous aspects, wherein the set-individual offset O is a non-zero offset selected individually for each set22within a frame88comprising a number of slots89.7. The wireless communications network of one of previous aspects,wherein a network controller36being in communication with the base station14is configured for determining an upper bound and a lower bound of the set-individual offset O and wherein the transmitter12is configured for determining the set-individual offset O so as to be within the lower bound and the upper bound; and/orwherein the network controller36is configured for determining the set-individual offset, wherein the base station14is configured for transmitting a signal to the transmitter12, indicating the determined set-individual offset O, wherein the transmitter12is configured for applying the set-individual offset according to the signal; and/orwherein the transmitter12is configured for selecting the set-individual offset O randomly.8. The wireless communications network of one of previous aspects, wherein a network controller36being in communication with the base station14is configured for determining a plurality of sets of offsets, each set of offsets containing a plurality of offset-values associated to a plurality of sets22of physical resources, wherein the transmitter12is configured for selecting one of the plurality of sets of offsets and to apply the set-individual offsets O to a plurality of sets22of physical resources within a frame889comprising a number of slots89.9. The wireless communications network of aspect 8, wherein the each of the sets of offset-values comprises a unique offset-pattern associated to the set of offset-values.10. The wireless communications network of one of previous aspects, wherein the second part signal422is at least a first re-transmission of the first part signal421, wherein the set-individual offset is selected such that the set-individual offset applied to the second part-signal422is associated with a number of prior transmissions.11. The wireless communications network of one of previous aspects, wherein a network controller36being in communication with the base station14is configured for determining the set-individual offset of a first slot89aor last slot89Nof a frame so as to exceed the frame88.12. The wireless communications network of one of previous aspects, wherein the base station14is configured for operating the wireless communications network cell100according to a sparse allocation scheme and/or wherein the transmitter12is configured for using the slots89according to the sparse allocation scheme.13. The wireless communications network of one of previous aspects, wherein the base station14is configured for operating the wireless communications network cell100according to a non-orthogonal multiple access scheme and/or wherein the transmitter12is configured for using the slots according to the non-orthogonal multiple access scheme.14. The wireless communications network of aspect 13, wherein the base station14is configured for operating the wireless communications network according to a frame structure, each frame88comprising a number of slots89, wherein the non-orthogonal multiple access scheme provides for a plurality of layers18, each layer18comprising a subset of the number of slots89, wherein the transmitter12is configured for using at least one layer18for transmission.15. The wireless communications network of aspect 14, wherein the transmitter12is configured for using at least a first and a second layer18within a frame88.16. The wireless communications network of aspect 15, wherein the first layer18and the second layer18are cyclically shifted within the plurality of layers.17. The wireless communications network of one of previous aspects, wherein the transmitter12is configured for dividing the signal16into the number of part signals42and/or to retransmit at least a part of the signal16as a part signal16.18. The wireless communications network of aspect 17, wherein the transmitter is configured for dynamically mapping the signal into a dynamically changing number of part signals.19. The wireless communications network of one of previous aspects, wherein the set-specific offset is defined for a group of transmitters, the group being formed based on at least one of:an application of the transmitter;a device type of the transmitter; anda service provided by the transmitter.20. Wireless Communications network comprising:a base station14configured for operating a wireless communications network cell100of the wireless communications network so as to provide communication in a plurality of slots88, each slot88comprising a plurality of associated physical resources;at least one transmitter12configured for transmitting a signal16in the wireless communications network cell100by mapping the signal16into a number of part signals42and for transmitting the number of part signals42associated to a corresponding number of slots using a corresponding number of sets22of physical resources, each set22containing at least a subset of the associated plurality of physical resources of the slot;wherein each set22of physical resources is received at the base station shifted with a frequency offset O1, O2, O12, O22with respect to a synchronized minimum frequency261,262of the slot88.21. The wireless communications network of aspect 20, wherein the frequency offset O1, O2, O12, O22is a set-individual offset O.22. A transmitter12comprising:an interface configured for transmitting a signal16in a wireless communications network cell100of a wireless communications network;a control unit configured for mapping the signal16into a number of part signals42and for transmitting the number of part signals42with a corresponding number of associated slots89of the wireless communications network cell100using a corresponding number of sets22of physical resources, each set22containing at least a subset of the associated plurality of physical resources of the slot89;wherein the control unit is configured for transmitting the number of part signals42with a set-individual offset O such that each set22of physical resources is shifted with respect to a synchronized start of the slot.23. A base station14configured for operating a wireless communications network cell100according to a wireless communications network scheme comprising a plurality of frames88, each frame88comprising a plurality of slots89, each slot89comprising a plurality of associated physical resources, the base station14comprising:an interface configured for receiving a first number of part signals42from a first transmitter121; and a second number of part signals42from a second transmitter122, each part signal42being associated to a slot89of a dedicated frame88, wherein each part signal89of the first number of part signals comprises a set-individual offset O within the first number and with respect to a synchronized start24of the slot 8; and wherein each part signal42of the second number part signals comprises a set-individual offset O within the second number and with respect to the synchronized start24of the slot88;a decoding unit configured for decoding the received first part signals42and the received second part signals42and for correcting interference caused by an overlap of the first part signals42with the second part signals42.24. Method for operating a wireless communications network, the method comprising:operating a wireless communications network cell100of the wireless communications network so as to provide communication in a plurality of slots89such that each slot89comprises a plurality of associated physical resources;transmitting a signal16in the wireless communications network cell by mapping the signal16into a number of part signals42;transmitting the number of part signals42with a corresponding number of associated slots89using a corresponding number of sets22of physical resources, each set22containing at least a subset of the associated plurality of physical resources of the slot89;such that each set22of physical resources is received at a base station14shifted with a set-individual offset O with respect to a synchronized start24,26of the slot89.25. Method for operating a wireless communications network, the method comprising:operating a wireless communications network cell100of the wireless communications network so as to provide communication in a plurality of slots88such that each slot88comprises a plurality of associated physical resources;transmitting a signal16) in the wireless communications network cell by mapping the signal16) into a number of part signals42);transmitting the number of part signals42with a corresponding number of associated slots89using a corresponding number of sets22of physical resources, each set22containing at least a subset of the associated plurality of physical resources of the slot89;such that each set22of physical resources is received at a base station14shifted with a frequency offset O1, O2, O12, O22with respect to a synchronized minimum frequency26of the slot88.26. Method for operating a transmitter12, the method comprising:transmitting a signal16in a wireless communications network cell100of a wireless communications network using an interface by mapping the signal16into a number of part signals42; and by transmitting the number of part signals42with a corresponding number of associated slots89of the wireless communications network cell100using a corresponding number of sets22of physical resources, each set22containing at least a subset of the associated plurality of physical resources of the slot89;transmitting the number of part signals42with a set-individual offset O such that each set22of physical resources is shifted with respect to a synchronized start24,26of the slot.27. Method for operating a base station14configured for operating a wireless communications network cell100according to a wireless communications network scheme comprising a plurality of frames88, each frame88comprising a plurality of slots89, each slot89comprising a plurality of associated physical resources, the method comprising:receiving a first number of part signals42from a first transmitter121; and receiving a second number of part signals42from a second transmitter122, each part signal42being associated to a slot89of a dedicated frame88, wherein each part signal42of the first number of part signals comprises a set-individual offset O within the first number and with respect to a synchronized start24,26of the slot; and wherein each part signal42of the second number part signals comprises a set-individual offset O within the second number and with respect to the synchronized start24,26of the slot; anddecoding the received first part signals42and the received second part signals42and for correcting interference caused by an overlap of the first part signals42with the second part signals42.28. Non transitory storage medium having stored thereon a computer program having a program code for performing, when running on a computer, a method according to one of aspects 24 to 27.

Although some aspects have been described in the context of an apparatus, it is clear that these aspects also represent a description of the corresponding method, where a block or device corresponds to a method step or a feature of a method step. Analogously, aspects described in the context of a method step also represent a description of a corresponding block or item or feature of a corresponding apparatus.

Depending on certain implementation requirements, embodiments of the invention can be implemented in hardware or in software. The implementation can be performed using a digital storage medium, for example a floppy disk, a DVD, a CD, a ROM, a PROM, an EPROM, an EEPROM or a FLASH memory, having electronically readable control signals stored thereon, which cooperate (or are capable of cooperating) with a programmable computer system such that the respective method is performed.

Some embodiments according to the invention comprise a data carrier having electronically readable control signals, which are capable of cooperating with a programmable computer system, such that one of the methods described herein is performed.

Generally, embodiments of the present invention can be implemented as a computer program product with a program code, the program code being operative for performing one of the methods when the computer program product runs on a computer. The program code may for example be stored on a machine-readable carrier.

Other embodiments comprise the computer program for performing one of the methods described herein, stored on a machine-readable carrier.

In other words, an embodiment of the inventive method is, therefore, a computer program having a program code for performing one of the methods described herein, when the computer program runs on a computer.

A further embodiment of the inventive methods is, therefore, a data carrier (or a digital storage medium, or a computer-readable medium) comprising, recorded thereon, the computer program for performing one of the methods described herein.

A further embodiment of the inventive method is, therefore, a data stream or a sequence of signals representing the computer program for performing one of the methods described herein. The data stream or the sequence of signals may for example be configured to be transferred via a data communication connection, for example via the Internet.

A further embodiment comprises a processing means, for example a computer, or a programmable logic device, configured to or adapted to perform one of the methods described herein.

A further embodiment comprises a computer having installed thereon the computer program for performing one of the methods described herein.

In some embodiments, a programmable logic device (for example a field programmable gate array) may be used to perform some or all of the functionalities of the methods described herein. In some embodiments, a field programmable gate array may cooperate with a microprocessor in order to perform one of the methods described herein. Generally, the methods may be performed by any hardware apparatus.

While this invention has been described in terms of several embodiments, there are alterations, permutations, and equivalents which fall within the scope of this invention. It should also be noted that there are many alternative ways of implementing the methods and compositions of the present invention. It is therefore intended that the following appended claims be interpreted as including all such alterations, permutations and equivalents as fall within the true spirit and scope of the present invention.

REFERENCES

[1] 3GPP: R1-1810623, Transmitter side signal processing of ACMA, Hughes[2] 3GPP: R1-1811274, “Enhanced SPS and grant-free transmissions”