CN112119664A - Multiple access techniques in cellular networks - Google Patents

Abstract

A method and apparatus for non-orthogonal multiple access, in which a UE controls selection of transmission parameters for uplink transmission, reducing control overhead compared to network hold control. The uplink transmission may include an indication of a transmission parameter, such as a modulation coding scheme.

Description

Multiple access techniques in cellular networks

Technical Field

The present invention relates to multiple access techniques in cellular networks, and more particularly to non-orthogonal multiple access (non-orthogonal multiple access) of uplink channels in cellular networks.

Background

Wireless communication systems, such as third generation (3G) mobile telephone standards and techniques are well known. The 3G standards and technologies were developed by the Third Generation Partnership Project (3 GPP). Third generation wireless communications were developed to support macro cellular mobile telephone communications. Communication systems and networks are evolving towards broadband mobile systems.

In a cellular Radio communication system, a User Equipment (UE) is connected to a Radio Access Network (RAN) via a Radio link. The RAN includes: a set of base stations providing radio links to UEs located in cells covered by the base stations; and an interface to a Core Network (CN) that provides overall Network control. It is to be understood that the RAN and CN each perform corresponding functions with respect to the entire network. For convenience, the term cellular network will be used to refer to the combined RAN & CN and it will be understood that the term is used to refer to the various systems for performing the disclosed functions.

The third generation partnership project has developed a so-called Long Term Evolution (LTE) System, i.e., an Evolved Universal terrestrial Radio Access Network (E-UTRAN), in which one or more macrocells are supported by a base station eNodeB or eNB (Evolved NodeB). Recently, LTE has further evolved towards so-called 5G or NR (New Radio technology) systems, in which one or more macrocells are supported by a base station gNB. NR proposes the use of an Orthogonal Frequency Division Multiplexing (OFDM) physical transmission format.

One trend in wireless communications is to provide lower latency and more reliable service. For example, NR is intended to support Ultra-reliable low-latency Communications (URLLC), and large Machine-Type Communications (mtc) is intended to provide low latency and high reliability for small data packets (typically 32 bytes). The user-plane (user-plane) delay is 1ms, and the reliability is 99.99999%. Other proposed service types include enhanced Mobile BroadBand (eMBB) for high data rate transmission, and large-scale Machine-Type Communication (mtc) for supporting a large number of devices over an energy-efficient Communication channel for a long life cycle.

Communication over the Physical radio link is defined by many channels, e.g. in the Uplink direction, a Physical Uplink Shared Channel (PUSCH) is used for transmission from the UE to the base station. The PUSCH is transmitted using a set of time (slot) and frequency resources. In conventional systems, only one UE transmits on each set of time and frequency resources, so there is no overlap between transmissions. In a conventional spatial multiplexing system (spatial multiplexing), only one UE per spatial layer (spatial layer) transmits signals on each set of time and frequency resources. While such resource allocation reduces interference between UEs, capacity is limited by the available resources.

Techniques such as non-orthogonal multiple access (NOMA) may be utilized to allow multiple UEs to transmit on a particular resource to increase the capacity of available time and frequency resources. Fig. 1 shows an example of NOMA transmission, where multiple PUSCHs are transmitted on overlapping resources. Each transmission includes a Multiple Access (MA) signature to identify the UE that is transmitting and may also include a DMRS to assist in demodulation of the signal.

At the base station, the lower power signal appears as noise on the higher power signal. The higher power signal may be demodulated directly by removing noise and then may be removed from the received signal to recover the lower power signal. Such a receiving end is called a Successive Interference Cancellation (SIC) receiving end, but other receiving techniques may be used.

Since uplink resources are used for more than one UE transmission, the NOMA technique is advantageous in that resource efficiency is improved.

mtc services are typically characterized by a large number of devices, occasionally transmitting small data packets (typically 10-75 bytes). For example, one cell is expected to support thousands of devices. In this case, overhead of a signaling channel for configuring uplink communication (e.g., a scheduling and Modulation Coding Scheme (MCS)) may be prohibited, and thus unlicensed transmission may be used for the uplink. Similarly, the number of devices may be much larger than the available number of MA signatures, thus preventing unique identification of the UE.

The UE may also not transmit the first time (from RRC IDLE (RRC IDLE) or RRC INACTIVE (RRC INACTIVE)) to RRC CONNECTED (RRC CONNECTED), thereby negating the ability to use RRC for UE transmission parameter configuration.

Therefore, there is a need for an improved NOMA uplink transmission system.

Disclosure of Invention

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

The present invention provides a method of uplink data transmission from a user equipment, UE, to a base station in a wireless cellular communication network, the uplink transmission using a non-orthogonal multiple access, NOMA, protocol, the method comprising the steps of: the UE selects a modulation coding scheme for uplink data transmission; and transmitting an uplink transmission using the modulation coding scheme, the uplink transmission including an indication of the selected modulation coding scheme; wherein the uplink transmission is transmitted using an unlicensed transmission protocol.

The modulation coding scheme may be selected from a subset of modulation coding schemes, where the subset of modulation coding schemes is a set selected from a larger set of modulation coding schemes available to the UE.

The indication of the modulation coding scheme may be transmitted in an uplink control information report.

The modulation coding scheme may be selected based on the performance of a previous set of uplink unlicensed NOMA transmissions.

The modulation coding scheme may be selected by selecting a modulation coding scheme that enhances or reduces robustness, respectively, based on a failure or success of a previous uplink unlicensed NOMA transmission.

The modulation coding scheme may be selected from an ordered list of coding schemes, the ordered list being ordered by robustness, each coding scheme having a robustness index.

Depending on the failure or success of at least one previous transmission, a coding scheme with a robustness index higher or lower than the robustness index of the coding scheme used for the previous transmission may be selected, respectively.

The robustness index may be higher or lower than the first step size or the second step size, respectively.

The robustness index may be higher if m consecutive uplink transmissions are not successfully acknowledged.

The robustness index may be lower if n consecutive uplink transmissions are successfully acknowledged.

The modulation coding scheme may be selected according to downlink performance information obtained from downlink synchronization.

The modulation coding scheme may be selected according to a BLER value.

The upstream transmission may include a multiple access signature (multiple access signature).

The selection of the modulation and coding scheme may be independent of the base station.

The CRC of the uplink transmission may be scrambled with the identity of the UE.

The identity may be a UE xrti or a UE ID.

The indication of the modulation coding scheme may be provided by a dedicated field in a PUSCH channel.

The dedicated field may include 2 to 5 bits.

The format of the indication of the modulation coding scheme may be defined by at least one RRC configuration message.

The RRC configuration message may include a set of parameters including a betaOffsetMCS-Index0 and a betaOffsetMCS-Index1, which provide an Index for the UE, respectively

For use when the UE multiplexes up to 2 MCS bits or more than 2 MACs and up to 5 MCS bits in PUSCH.

The parameters used by the UE in the algorithm to select the modulation and coding scheme may be defined by the base station.

The invention also provides a mobile device configured to perform the above method.

The non-transitory computer readable storage medium may include at least one of a hard disk, a Compact Disc Read Only Memory (CD-ROM), an optical Memory, a magnetic Memory, a Read Only Memory (ROM), a Programmable Read Only Memory (PROM), an Erasable Programmable Read Only Memory (EPROM), an Electrically Erasable Programmable Read Only Memory (EEPROM), and a Flash Memory.

Drawings

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Elements in the figures have been simplified and are not necessarily drawn to scale. For ease of understanding, reference numerals have been included in the various figures.

Fig. 1 is an exemplary diagram of NOMA transmission.

Fig. 2 is a diagram illustrating an uplink transmission method.

Fig. 3 is a schematic diagram of a receiving method.

Fig. 4 is a diagram illustrating an uplink transmission method.

Fig. 5 is a schematic diagram of a receiving method.

Detailed Description

The embodiments described herein are only a few embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

As described above, overhead issues may prevent the use of grant-based UL NOMA transmissions, especially for devices using mtc-type services, thereby limiting the ability of the base station to select and configure UL transmission parameters. Furthermore, each MA signature may be used by multiple UEs, thereby preventing identification of UEs based on MA signatures.

One way to identify the UE is to include the xrrnti or UE ID of the UE in the UCI of the PUSCH transmission multiplex. Although this may identify the UE directly, 16 or 24 bits of overhead may be required over a 10-150 byte payload. In addition, these bits must be encoded in a robust (robust) and fixed MCS, thus further increasing overhead. An alternative that does not require any overhead is to use the UE identity to scramble the CRC transmission. Although in this case the UE can only be identified after data demodulation and CRC checking, the reduced overhead may be more attractive, especially for the transmission of small data.

Fig. 2 shows a flow chart of a method of transmitting a signal from a UE to a base station. In step 20, the UE prepares for transmission on the PUSCH the required data, including a MA signature selected from a set of MA signatures assigned to the UE. The UE may randomly select the MA signature. The UE scrambles CRC of the prepared data using xrrnti or UE ID of the UE in step 21, and transmits a message on PUSCH using a grant-free transmission protocol in step 22. Multiple UEs connected to a particular base station may use the method of fig. 2 at the same time, and thus resources may be occupied by transmissions of more than one UE. Similarly, more than one message may be transmitted with the same MA signature.

Fig. 3 illustrates a method of decoding a received transmission and identifying a UE that is transmitting. In step 30, the base station receives NOMA transmissions from one or more UEs and detects MA signatures. Since each MA signature may be shared among more than one UE, the signature allows the base station to identify a group of UEs that may have received a transmission, rather than uniquely identifying the UEs.

In step 31, the base station demodulates the received signal using a blind detection algorithm (blind detection algorithm). At this stage of the process, the base station does not know the identity of the UE being transmitted, nor the MCS used for the transmission. A SIC type receiving end can be utilized to demodulate the received signal and recover each of the overlapping transmissions. Due to the insufficient knowledge of the received signal by the base station, the base station may need to test a large number of options during blind demodulation. That is, blind demodulation can be performed in a larger search space. Recovering multiple NOMA signals using a SIC receiving end may make the process more challenging.

After signal recovery, the CRC is checked and descrambled (descrambled) to identify the xrrnti or UE ID of the UE that the UE uses to scramble (descramble) the CRC, step 32.

Selecting a unique MCS for all relevant devices may reduce the search space for the demodulation process. Therefore, the blind demodulation process only needs to test the MCS. However, the selected MCS must be the one that is most robust in performance, since it will be used in all cases, and therefore it must support worst case link conditions. Usually, a QPSK MCS with a lower code rate is used, which has stronger robustness (robust), but the spectrum efficiency is poor.

These standards (e.g., TS 28.214, Table 6.1.4.1-1) define a set of possible MCS schemes. To reduce the set of MCSs that must be tested during blind demodulation, a subset of MCSs may be allocated to UEs transmitting NOMA traffic (traffic), thereby reducing the search space. The scheme can flexibly select a proper MCS according to the link condition, but simultaneously considers the complexity of demodulation. When transmitting the NOMA message using the procedure shown in fig. 1, the UE selects an appropriate MCS from the allocated subset.

Due to the infrequent nature of mtc transmissions, it is unlikely that the base station will acquire enough signals from the UE to know the current channel conditions and therefore select a suitable MCS. In addition, the overhead of transmitting the configuration message to each UE may be large. Instead, the UE must synchronize on the downlink channel before transmission, so the UE has up-to-date information about the downlink channel conditions. The downlink channel condition is a reasonable indicator (reasonable indicator) of the uplink channel condition and thus can be used to guide the selection of a suitable MCS irrespective of the base station.

The UE may select the MCS using any suitable procedure. In an example, the UE may pre-configure a particular MCS. For example, a low-end (low-end) UE transmitting a small amount of data may always utilize a simple MCS, such as QPSK.

Fig. 4 shows a method of selecting MCS for NOMA UL transmission. In step 40, the UE wakes up and performs DL synchronization before NOMA transmission. Based on the measured DL SINR and optionally the ACK/NACK history for the previous PUSCH transmission (41), the UE selects the appropriate MCS in step 42.

In step 43, the UE performs data transmission on the PUSCH using the selected MCS, e.g., as shown in fig. 2. The transmitted message may include an indication of the selected MCS, which may be utilized by the base station at step 44 to demodulate the received signal. Upon demodulation, the base station transmits an ACK/NACK at step 45.

The UE may update its ACK/NACK history for use in future transmissions and may then return to a sleep state (sleep).

As described above, the MCS for each UL NOMA transmission is selected by the UE (i.e., the UE performs link rate adaptation). Although the MCS may be selected based on conventional BER or BLER statistics, this is unlikely to be effective in mtc type systems that rarely perform small data transmissions (small transmissions) and therefore link characteristics may vary greatly between transmissions.

The procedures listed below may be used to select an MCS for UL NOMA transmissions, such as the method of fig. 4. The method increases or decreases the selected MCS with the latest PUSCH transmission result, which is expressed as follows: -

If lasttxfailed, MCS max (MCS-K1, MCSmin), end;

if lastntxsuceded, MCS min (MCS + K2, MCSmax) ends.

MCSmin is the index of the available MCS with the best robustness (e.g., 0 for NR OMA), and MCSmax is the index of the highest throughput MCS (index).

If the last NOMA Tx of the UE is not acknowledged, lasttxfailed is 1, otherwise it is 0.

K1 and K2 are integer values greater than or equal to 1.

If the last m NOMA UL transmissions fail, lasttxfailed is 1, and m is a configurable integer greater than or equal to 1.

If the last n NOMA UL transmissions have succeeded, lastntxsuceded is 1, n being a configurable integer greater than or equal to 1.

Thus, when ordered according to robustness, the process increases or decreases the MCS according to the success or failure of a configurable number of the most recent PUSCH transmissions. As described above, if there is no ACK/NACK (acknowledged/unacknowledged) history (e.g., no ACK transmission, or insufficient previous transmission), the MCS may be selected based on an evaluation of the signal quality of the downlink synchronization or other channel quality (e.g., DL SINR, DL RSRP, DL RSSI, or any equivalent value).

Generally, the selection of the MCS can be said to be based on the latest events (receiver events) related to the transmission channel.

The selected MCS may be indicated in the PUSCH using a "UCI reporting in physical uplink shared channel" (clause 9.3 in TS 38.213) procedure in which the UE multiplexes UCI information in the PUSCH.

A new offset value, specific to the signaling MCS, may be defined by the UE to determine the number of resources used for MCS indication in the multiplexed PUSCH. The offset value may be sent to the UE by higher layers or by scheduling PUSCH transmission in DCI format. In particular, a new set of parameters, betaoffsetmc-index0 and betaoffsetmc-index1, respectively, provides the index for the UE

For use when the UE multiplexes up to 2 MCS bits or more than 2 MCS bits and up to 5 MCS bits, respectively, in the PUSCH.

Fig. 5 shows a flow chart of a NOMA PUSCH reception method when the PUSCH comprises an indication of an MCS. In step 50, the base station detects the MA signature (which, as described above, allows to identify the group of UEs to which the transmitting UE belongs), and then in step 51, the base station demodulates the MCS field. At step 52, the received signal is demodulated and recovered using the indicated MCS, e.g., using a SIC receiving end. Since the MCS is known, there is no penalty (penalty) incurred at this stage due to lack of knowledge of the particular UE transmitting the signal. The UE may be identified in step 53 after CRC checking and descrambling from which the xRNTI or UE ID used for scrambling the CRC may be recovered.

Although not shown in detail, any device or apparatus forming part of a network may comprise at least a processor, a memory unit, and a communication interface, wherein the processor unit, the memory unit, and the communication interface are configured to perform the method of any aspect of the present invention. Further options and selections are described below.

The signal processing functions in the embodiments of the present application, particularly the signal processing capabilities of the gNB and the UE, may be implemented by computing systems or architectures that are well known to those skilled in the art. The computing system may be a desktop, laptop or notebook computer, hand-held computing device (PDA, cell phone, palmtop, etc.), mainframe, server, client, or any other type of special or general purpose computing device as may be satisfactory or applicable to a given application or environment. The computing system may include one or more processors that may execute a general or special purpose processing engine such as, for example, a microprocessor, microcontroller or other control module.

The computing system may also include a main Memory, such as Random Access Memory (RAM) or other dynamic Memory, for storing information and instructions to be executed by the processor. The main memory may also be used for storing temporary variables or other intermediate information during execution of instructions by the processor. The computing system may also include a Read Only Memory (ROM) or other static storage device for storing static information and instructions for execution by the processor.

The computing system may also include an information storage system including, for example, a media drive and a removable storage interface. The media drive may include a drive or other mechanism to support fixed or removable storage media, such as a hard disk drive, a floppy disk drive, a magnetic tape drive, an optical disk drive, a compact disk drive (CD) or Digital Video Drive (DVD) read-write drive (R or RW), or other fixed or removable media drive. The storage medium may include, for example, a hard disk, floppy disk, magnetic tape, optical disk, CD, DVD, or other fixed or removable medium that is read by and written to by a media drive. The storage media may include a computer-readable storage medium having stored thereon particular computer software or data.

In alternative embodiments, the information storage system may include other similar components for allowing computer programs or other instructions or data to be loaded into the computing system. These components may include, for example, a removable storage unit and interface, such as a program cartridge and cartridge interface, a removable memory (e.g., a flash memory or other removable memory module) and memory slot, and other removable storage units and interfaces that allow software and data to be transferred from the removable storage unit to the computing system.

The computing system may also include a communication interface. The communication interface may be used to allow software and data to be transferred between the computing system and external devices. For example, the communication interfaces can include a modem, a network interface (such as an Ethernet or other network card), a communication port (such as a Universal Serial Bus (USB) port), a PCMCIA slot and card, and the like. Software and data transferred via the communications interface are in the form of signals which may be electronic, electromagnetic, optical or other signals capable of being received by the communications interface medium.

In this application, the terms "computer program product," "computer-readable medium," and the like are used generally to refer to tangible media, such as memory, storage devices, or storage units. These and other forms of computer-readable media may store one or more instructions for use by a processor, including a computer system, to cause the processor to perform specified operations. These instructions, which are generally referred to as "computer program code" (which may be grouped in the form of computer programs or other groupings), when executed, enable the computer system to perform functions of embodiments of the present application. It is noted that the code may directly cause the processor to perform specified operations, may be compiled to do so, and/or may be combined with other software, hardware, and/or firmware elements (e.g., libraries for performing standard functions) to do so.

The non-computer readable medium may comprise at least one from the group of: hard disks, Compact disk Read Only memories (CD-ROMs), optical storage devices, magnetic storage devices, Read Only Memories (ROMs), Programmable Read Only Memories (PROMs), Erasable Programmable Read Only Memories (EPROMs), Electrically Erasable Programmable Read Only Memories (EEPROMs), and Flash memories (Flash memories).

In embodiments implemented by software, the software may be stored in a computer-readable medium and loaded into the computing system using, for example, a removable storage drive. A control module (e.g., software instructions or executable computer program code) executed by a processor in a computer system causes the processor to perform functions as described herein.

Further, the present application may be applied in any circuit for performing signal processing functions in a network element. For example, it is further contemplated that a semiconductor manufacturer may employ the innovative concepts in the design of a stand-alone device, which may be a microcontroller (DSP) of a digital signal processor, an Application Specific Integrated Circuit (ASIC), and/or any other subsystem element.

For clarity of description, the foregoing description has described embodiments of the present application with reference to a single processing logic. However, the present application may equally well implement signal processing functions by means of a plurality of different functional units and processors. Thus, references to specific functional units are only to be seen as references to suitable means for providing the described functionality rather than indicative of a strict logical, physical structure or organization.

Aspects of the present application may be implemented in any suitable form including hardware, software, firmware or any combination of these. The present application may optionally be implemented, at least partly, as computer software, a computer software component, such as an FPGA device, running on one or more data processors and/or digital signal processors or configurable modules. Thus, the elements and components of an embodiment of the application may be physically, functionally and logically implemented in any suitable way. Indeed the functionality may be implemented in a single unit, in a plurality of units or as part of other functional units.

Although the present application has been described with reference to the preferred embodiments, the above-described preferred embodiments are not intended to limit the present application, and the scope of the present application is defined by the following claims. Furthermore, while descriptions of features related to particular embodiments may appear, one skilled in the art may, in light of the present disclosure, appreciate various features of such embodiments. In the claims, the term "comprising" does not exclude the presence of other elements or steps.

Further, although individually listed, a plurality of means, elements or method steps may be implemented by e.g. a single unit or processor. Furthermore, although different features may comprise different claims, these may possibly advantageously be combined, and the inclusion in different claims does not imply that a combination of features is not feasible and/or advantageous. Likewise, the inclusion of a feature in one set of claims does not imply a limitation to this set of claims, but rather indicates that the feature is equally applicable to other claim categories, as appropriate.

Further, the ordering of features in the claims does not imply that the features must be performed in a particular order, and in particular the order of individual steps in a method claim does not imply that the steps must be performed in this order. Rather, the steps may be performed in any suitable order. Furthermore, singular references do not exclude a plurality. Thus, the singular forms "a", "an", "first", "second", etc. do not exclude the plural forms.

Although the present application has been described with reference to the preferred embodiments, the above-described preferred embodiments are not intended to limit the present application, and the scope of the present application is defined by the following claims. Furthermore, while descriptions of features related to particular embodiments may appear, one skilled in the art may, in light of the present disclosure, appreciate various features of such embodiments. In the claims, the term "comprising" or "including" does not exclude the presence of other elements.

Claims (22)

1. A method of uplink data transmission from a UE to a base station in a wireless cellular communication network, wherein the uplink transmission uses a non-orthogonal multiple access, NOMA, protocol, the method comprising the steps of:

the UE selects a modulation coding scheme for uplink data transmission; and the number of the first and second groups,

transmitting an uplink transmission using the modulation coding scheme, the uplink transmission including an indication of the selected modulation coding scheme;

wherein the uplink transmission is transmitted using an unlicensed transmission protocol.

2. The method of claim 1, wherein the modulation and coding scheme is selected from a subset of modulation and coding schemes, wherein the subset of modulation and coding schemes is a set selected from a larger set of modulation and coding schemes available to the UE.

3. The method according to claim 1 or 2, wherein the indication of the modulation coding scheme is transmitted in an uplink control information report.

4. Method according to any of claims 1 to 3, wherein the modulation and coding scheme is selected based on the performance of a previous set of uplink unlicensed NOMA transmissions.

5. The method according to any of claims 1 to 4, wherein the modulation coding scheme is selected by selecting a modulation coding scheme that increases or decreases robustness based on a failure or success, respectively, of a previous uplink unlicensed NOMA transmission.

6. The method according to any of claims 1 to 4, wherein the modulation coding scheme is selected from an ordered list of coding schemes, the ordered list being ordered by robustness, each coding scheme having a robustness index.

7. Method according to claim 6, wherein a coding scheme with a robustness index higher or lower than the robustness index of the coding scheme used for the previous transmission is selected depending on the failure or success, respectively, of at least one previous transmission.

8. The method of claim 7, wherein the robustness index is higher or lower than the first step size or the second step size, respectively.

9. The method of claim 7, wherein the robustness index is higher if m consecutive uplink transmissions are unsuccessfully acknowledged.

10. The method of claim 7, wherein the robustness index is lower if n consecutive uplink transmissions are successfully acknowledged.

11. The method according to any of claims 1 to 10, wherein the modulation coding scheme is selected based on downlink performance information obtained from downlink synchronization.

12. The method according to any of claims 1 to 11, wherein said modulation coding scheme is selected based on BLER values.

13. The method according to any of claims 1 to 12, wherein the uplink transmission comprises a multiple access signature.

14. The method according to any of claims 1 to 13, wherein the modulation and coding scheme is selected independently of the base station.

15. The method of any of claims 1 to 14, wherein the CRC of the uplink transmission is scrambled with an identity of the UE.

16. The method of claim 14, wherein the identity is a UE xrntiti or a UE ID.

17. The method according to any of claims 1 to 16, wherein the indication of the modulation coding scheme is provided by a dedicated field in a PUSCH channel.

18. The method of claim 17, wherein the dedicated field comprises 2 to 5 bits.

19. The method according to any of claims 1 to 18, wherein the format of the indication of the modulation coding scheme is defined by at least one RRC configuration message.

20. The method of claim 19 wherein the RRC configuration message includes a set of parameters including betaOffsetMCS-Index0 and betaOffsetMCS-Index1, which provide an Index for the UE, respectively

For use when the UE multiplexes up to 2 MCS bits or more than 2 MACs and up to 5 MCS bits in PUSCH.

21. The method according to any of claims 1 to 20, characterized in that the parameters used by the UE in the algorithm to select the modulation coding scheme are defined by the base station.

22. A mobile device configured to perform the method of any of claims 1 to 21.

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