KR20180133175A - Signal processing method, apparatus and base station using combined non-orthogonal multiple access and generalized space shift keying - Google Patents

Abstract

The present invention relates to a signal processing method, apparatus, and base station combined with NOMA and GSSK. The present invention is characterized by combining a GSSK scheme using antenna index information of a space area for external users with a NOMA scheme using distribution of a power area. According to the present invention, there is no limitation in the number of transmission antennas, and only the antenna index information is transmitted to users outside a cell. Thus, it is possible to reduce signal interference and improve frequency efficiency in comparison to when using only NOMA. Thus, more users can be secured. In addition, a user terminal for receiving a signal of the base station in which NOMA and GSSK are combined has an effect that a step of SIC is reduced by the number of GSSK users when a NOMA scheme is received, and BER is improved by using MLD as a signal detector when GSSK is received.

Description

Technical Field [0001] The present invention relates to a signal processing method, apparatus and base station combining NOMA and GSSK, and more particularly, to a signal processing method, apparatus and base station combining NOMA and GSSK,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal processing method, apparatus and base station combining NOMA (Non-Orthogonal Multiple Access) and GSSK (Generalized Space Shift Keying) A signal processing method, an apparatus, and a base station for improving frequency efficiency and reducing SIC (Successive Interference Cancellation) of a user terminal by combining a GSSK scheme using an antenna index information of a spatial domain for an outer user will be.

NOMA is one of the promising 5G technologies that can efficiently utilize frequency and time resources to achieve high frequency efficiency. The NOMA technique can use the power allocation to increase the system capacity, superposition coding in the transmitter, and SIC in the receiver, so that multiple signals can be transmitted at the same time using the same frequency band. However, since NOMA is based on power allocation, there is a problem that the channel gain difference between users is small and the performance of cell outer users is deteriorated. In other words, since NOMA multiplexes users by using power distribution, the cell users who are allocated maximum power are slowed down by Inter Cell Interference (ICI). In order to solve the problems of NOMA, technologies such as power allocation optimization, scheduling, and antenna allocation optimization have been proposed.

MIMO (Multiple-Input-Multiple-Output) technology is one of promising technologies to improve the frequency efficiency. SM (Spatial Modulation) is a new type of MIMO modulation technique . In order to maximize the gain of SM, technologies such as QSM (Quadrature Spatial Modulation), ESM (Enhanced Spatial Modulation) and QOS-SM (Quasi-Orthogonal Sequence Spatial Modulation) have been proposed. However, since the SM transmits the antenna information and the symbol information together, the complexity is high, which is a problem in implementation. SSK (Space Shift Keying), which transmits signals using only antenna information based on SM, has been proposed. However, there is a problem that the number of transmit antennas is limited due to the use of SSK. On the other hand, since the GSSK uses a plurality of active transmit antennas and uses the combination of antennas as a transmittable antenna set, there is no restriction on the number of transmit antennas, and more data than the SSK can be transmitted using the same number of transmit antennas .

A 10-2016-0091791 A.

 Jeyadeepan Jeganathan, et. al. &Quot; Generalized space shift keying modulation for MIMO channels ", IEEE 19th International Symposium on Personal, Indoor and Mobile Radio Communications. IEEE, 2008.

The present invention has been devised to solve the problems of the related art as described above, and it is an object of the present invention to improve the frequency efficiency by combining the NOMA scheme using the power region distribution and the GSSK scheme using the antenna index information of the spatial domain for outer users A signal processing method, an apparatus, and a base station.

It is another object of the present invention to reduce the SIC level of the terminal receiving the NOMA.

Another object of the present invention is to improve a bit error rate (BER) of a cell outer user terminal receiving GSSK.

According to an aspect of the present invention, there is provided a method for controlling a channel gain of a terminal in a mobile communication system, the method comprising: calculating a channel gain of each terminal in a channel and selecting a terminal from the terminal having the lowest channel gain; A signal processor for assigning a transmission scheme using antenna index information to the selected specific terminal and allocating a multiplexing scheme using power distribution to terminals other than the specific terminal; And transmitting the super-coded signal using the antennas activated by the antenna mapping to the specific terminal and transmitting the signal using specific antennas selected based on the antenna index information to the terminals other than the specific terminal A base station apparatus is provided.

The selection of the specific terminal can be selected based on the state of the channel.

The transmission scheme using the antenna index information may be a GSSK scheme.

The multiplexing scheme using the power distribution may be a NOMA scheme.

The antenna mapping may be such that all transmission antennas and active transmission antennas are mapped according to the GSSK scheme.

According to another aspect of the present invention, there is provided a mobile station comprising: a determination unit determining whether a signal received from a base station is a signal superposed on a power region or a signal based on antenna index information; A first reconstructor for reconstructing the superimposed coded signal using SIC; And a second reconstructor for reconstructing a coded signal based on the antenna index information.

The determination unit may determine based on information including the pilot signal received from the base station.

The second restoration unit may select an antenna index from the mapping table and use the selected antenna index as information.

The second restoration unit may detect a signal using the MLD.

The superposition coded signal may be a signal coded by the NOMA method.

The coded signal based on the antenna index information may be a signal coded by the GSSK scheme.

According to another aspect of the present invention, there is provided a method of processing a signal of a base station, the method comprising: calculating a channel gain of each terminal in a channel; Selecting; Allocating a transmission scheme using antenna index information to the selected specific terminal and assigning a multiplexing scheme using power allocation to terminals other than the specific terminal; And transmitting a superposition-coded signal using the antennas activated by the antenna mapping to the specific terminal, and transmitting signals to the terminals other than the specific terminal using specific antennas selected based on the antenna index information A signal processing method is provided.

The selection of the specific terminal can be selected based on the state of the channel.

The antenna mapping may be such that all transmission antennas and active transmission antennas are mapped according to the GSSK scheme.

According to another aspect of the present invention, there is provided a signal processing method for a terminal, including: a signal received from a base station, the signal being superposition-coded in a power domain, Determining whether the signal is a signal; If the received signal is a superposition coded signal, reconstructing it using SIC; And if the received signal is a coded signal based on the antenna index information, selecting the antenna index from the mapping table and using the selected antenna index as information.

The determining may be based on information including the pilot signal received from the base station.

The coded signal based on the antenna index information can detect a signal using MLD.

According to another preferred embodiment, there is provided a computer program stored in a computer-readable recording medium for executing a method according to each of the above-described methods.

According to still another preferred embodiment, there is provided a computer-readable recording medium on which a program for executing the above-described respective methods is recorded.

As described above, according to the present invention, a NOMA scheme using a power area distribution is allocated to some users based on a channel state and a channel gain of user terminals, and an antenna index information of a spatial domain is used for a remaining user, GSSK scheme, transmitting a super-coded signal using the antennas activated by the GSSK antenna mapping to the NOMA user, and transmitting the super-coded signal to the GSSK user using the specific antennas selected based on the antenna index information. By providing a signal processing method, apparatus, and base station that combine NOMA and GSSK, there is no restriction on the number of transmit antennas. By transmitting only the antenna index information to the cell outer user, signal interference can be reduced. Get more users by improving And it is.

The user terminal receiving the signal of the base station combined with the NOMA and the GSSK has an effect of reducing the number of steps of the SIC by the number of GSSK users when receiving the NOMA scheme. Maximum Likelihood Detector) is used to improve the BER.

1 is a conceptual diagram showing a conventional NOMA wireless communication environment.
2 is a conceptual diagram illustrating a wireless communication environment according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating a frequency band according to an embodiment of the present invention in comparison with the prior art.
4 is a graph simulating frequency efficiency according to an embodiment of the present invention.
5 is a block diagram illustrating a configuration of a base station according to an embodiment of the present invention.
6 is a diagram illustrating a specific example of an antenna mapping table according to an embodiment of the present invention.
7 is a block diagram illustrating a configuration of a base station according to another embodiment of the present invention.
8 is a flowchart illustrating a specific example of a signal processing method of a base station according to another embodiment of the present invention.
9 is a block diagram illustrating a configuration of a UE according to another embodiment of the present invention.
10 is a flowchart illustrating a specific example of a signal processing method of a terminal according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. In the following description, only parts necessary for understanding the operation according to the embodiment of the present invention are shown and described, and the other parts of the drawings and descriptions are omitted so as not to obscure the gist of the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In addition, terms and words used in the following description and claims should not be construed to be limited to ordinary or dictionary meanings, but are to be construed in a manner consistent with the technical idea of the present invention As well as the concept.

Throughout the specification, when a part is referred to as being "connected" to another part, it is not limited to the case where it is "directly connected," but is "electrically connected" Or wirelessly or wirelessly over a wired / wireless network. Also, when a part is referred to as " including " an element, it does not exclude other elements unless specifically stated otherwise.

For simplicity of explanation, one or more methods are shown and described herein as a series of steps, for example in the form of a flowchart or a flowchart, but the present invention is not limited by the order of the steps, As it can be done in a different order than that shown and described herein or concurrently with other steps. Furthermore, not all illustrated steps may have to be implemented in accordance with the present invention.

In describing the various embodiments of the present invention, corresponding elements are denoted by the same names and the same reference numerals. In order to explain the embodiments of the present invention, the size of components, the thickness of lines, and the like in the drawings referred to may be exaggerated for the sake of understanding.

The present invention relates to a signal processing method for improving the frequency efficiency and reducing the SIC of a user terminal by combining a signal processing method using a power domain distribution and a signal processing method using an antenna index information of a spatial domain for an outer user, And a base station.

Although the NOMA method is described as a main example as the above-mentioned " signal processing method using distribution of the power region " throughout the specification, the present invention is not limited to the NOMA method, and various methods such as a method similar to the NOMA method, Is used.

Although the GSSK scheme is described as a main example as the above-mentioned " signal processing scheme using the antenna index information of the spatial domain ", the present invention is not limited to the GSSK scheme, and various schemes such as a GSSK scheme or a GSSK scheme Is used.

1 is a conceptual diagram showing a conventional NOMA wireless communication environment.

Referring to Figure 1, a base station 10 and user terminals 21, 22 are shown.

The base station 10 is a base station that provides mobile communication services to a plurality of user terminals 21 and 22, and may be displayed as a NodeB, an eNodeB, or the like.

The terminals 21 and 22 may be represented by user equipment (UE) and mobile station (MS), and may be mobile or stationary user terminals.

NOMA is one of the promising next generation mobile communication technologies and it operates based on power distribution and SIC unlike the existing multiple access technology Orthogonal Multiple Access (OMA). Because power splitting is used to multiplex signals, multiple users can use the same frequency domain at the same time. In NOMA, users are multiplexed in the power domain and each user is assigned power by their channel gain.

At this time, generally, the power ratio is allocated to the terminal 21 which is closer to the terminal 22, which is farther from the base station 10, so that the power ratio is distributed differently because the nearby terminal 21 uses the SIC Thereby removing the signal of the user located far away. In FIG. 1, transmission power ratios for respective terminals are differently allocated.

Figure 1 is a system model of NOMA when there are two users. UE1 21, which is a user close to the base station, can remove the signal of UE2 and decode the signal using SIC. Also, the signal transmitted to the UE 2 (22) is attenuated and the signal of the UE 1 (21) acts like a negligible noise, so that the original signal can be decoded without using the SIC. Assuming that there are three users and the UE 3 is farther from the base station 10 than the UE2 22, since signals of all users are included in the signals received by the UE 1, The UE 3 and the UE 2 are sequentially removed, and the signal of the last remaining UE 1 (21) is decoded. The more users, the greater the proportion of this signal cancellation process.

In the NOMA, the cell outer user, that is, the user 22 farthest from the base station has the lowest frequency efficiency. Although NOMA is a next-generation communication candidate technology with excellent frequency efficiency, since the signal is transmitted by allocating power according to the channel gain, the gain is reduced when the difference in channel gain between users is small. Also, more power is allocated to a cell outside user having a relatively poor channel environment, so that a cell outside user is exposed to large noise and performance is lower than that of a cell center user.

FIG. 2 is a conceptual diagram illustrating a wireless communication environment according to an embodiment of the present invention. FIG. 3 is a diagram comparing frequency bands with the prior art, FIG. 4 is a graph comparing and simulating frequency efficiency, FIG. 6 is a diagram showing a specific example of the antenna mapping table. FIG.

Referring to Figure 2, a base station 10 and user terminals 21, 22, 23, 24 are shown. In order to improve the frequency efficiency, the base station 10 is a base station that performs signal processing by combining a NOMA scheme using a power area distribution and a GSSK scheme using outer-layer antenna index information for outer users.

In order to solve the problem of the NOMA method described in FIG. 1, the user terminal 24 remote from the base station or communicating using the GSSK method is used in the case of the user terminal 24 of the cell, and the remaining terminals 21, 22, FIG. Although four terminals are shown in FIG. 2, the present invention is not limited thereto. Also, although the GSSK is used for the terminal 24 that is the farthest and the terminals 21, 22, and 23 are shown using the NOMA, the present invention is not limited thereto.

Conventional modulation schemes mainly transmit information using amplitude, frequency, phase, or a combination of these. However, recently proposed SSK and GSSK transmit information using spatial domain, ie, antenna information, as a modulation method for multiple wireless antenna systems. In addition, since SSK and GSSK transmit only antenna index information, not data symbols, there are disadvantages in that the number of bits that can be transmitted at one time in the same environment is smaller than that of SM. However, because it uses only antenna index information, it shares the advantages of SM and has lower complexity than SM.

In particular, since GSSK uses a plurality of active transmission antennas, it is advantageous to transmit more information than existing SSK using a combination of antennas.

In this embodiment, four users are assumed, and the channel gain of the four users is the highest in the UE1 21 and the lowest in the UE4 24 in the order of the closest from the base station 10. [

The base station 10 may calculate the channel gain of each of the terminals 21, 22, 23 and 24 in the channel and select a terminal from the terminal having the smallest calculated channel gain. A transmission method (GSSK, etc.) using antenna index information may be allocated to the selected specific terminal, and a multiplexing method (NOMA or the like) using power distribution may be allocated to terminals other than the specific terminal.

At this time, the UE 4 (24) having the lowest channel gain is regarded as a cell outer user and uses the spatial domain in the GSSK scheme. The remaining three user terminals 21, 22, and 23 using NOMA can distribute power using fractional transmit power allocation (FTPA) and transmit signals using superposition coding.

The number of users assigned to the GSSK scheme depends on the state of the channel, and the optimal number of users can be calculated. Since the state of the channel varies with each transmission, the optimal allocation can be continuously changed have. In this embodiment, the GSSK scheme is allocated only to the UEs 4 and 24 having the lowest channel gains. However, the GSSK scheme may be assigned to the UEs 23 and 23 having the lowest channel gain, It is not.

Referring to FIG. 3, it is assumed that the number of users is 6 and the bandwidth allocated to each user is B, which is a comparison between the conventional system and the frequency band of the system according to the present invention. And NOMA assumes that two users are assigned to overlap.

3 (a) shows a case in which only NOMA is used, a total bandwidth of 3B is required for 6 users to transmit data.

However, FIG. 3B and FIG. 3C show a case where the SSK and the GSSK are combined in the NOMA scheme. Since one user uses the spatial domain, the same user can be supported only by the bandwidth of 2B . Therefore, it can be seen that combining NOMA with the spatial domain scheme has superior frequency efficiency compared to the conventional NOMA.

3 (b) and 3 (c), it is possible to confirm how many transmit antennas are activated (shown by a black square) in the spatial domain. In FIG. 3 (b), the SSK has only one active transmission antenna, but FIG. 3 (c) GSSK can have a plurality of active transmission antennas without restriction.

Referring to FIG. 4, there is shown a graph simulating the frequency efficiency of the conventional NOMA system and the NOMA-GSSK system according to the present invention.

Table 1 shows the variables used as examples of this comparison simulation.

Number of receive antennas 4 Number of transmit antennas 4 to 8 Number of all users 4 Signal-to-noise ratio 0 to 20 dB Channel environment Rayleigh Fading Noise AWGN

It is assumed that there are four users in the cell, and each transmission signal passes through an independent Rayleigh fading channel. The comparison between the case of using the existing NOMA system and the case of using the NOMA-GSSK system according to the present invention is compared. When using NOMA-GSSK, three users use NOMA and the other one uses antenna information. Here, the total number of transmit antennas is M _t , and the number of active transmit antennas is M _a .

As can be seen from the graphs, the NOMA-GSSK combining method according to the present invention is superior to the conventional NOMA method in terms of frequency efficiency.

Referring to FIG. 5, there is shown a model of a transmission terminal of a base station 10 when K users are all users.

Assuming that K users are uniformly distributed in the cell, we assume that K-1 users use NOMA and the remaining cell users use GSSK. Then, the channel gain of each user is h _{1 &} gt; h _{2 &} gt; > h _{k -1} > h _k , the user UE (K) having the lowest channel gain can be regarded as a cell outer user and can use the spatial domain. At this time, K-1 users using NOMA can distribute power using FTPA and transmit signals using superposition coding.

By the antenna selection shown in Fig. 5, UE1, UE2, ... , The superposed coded symbols of the users of UE (K) may be transmitted using the specific transmit antennas ( M _a ) activated by antenna mapping to GSSK among all transmit antennas ( M _t ) using the NOMA technique. The UE (K), which is a cell outer user, can transmit data symbols using a specific antenna set selected based on antenna index information.

Referring to FIG. 6, a specific example of the antenna mapping table of the GSSK is shown (see Non-Patent Document 1).

In SSK, the number of transmission antennas is limited to 2 ^x , but since GSSK uses a combination of transmission antennas, there is no restriction on the number of transmission antennas. The GSSK may have multiple active transmit antennas and a total transmit antenna other than a multiple of two. Since GSSK uses a number of active transmit antennas unlike SSK, it can transmit more information than SSK when the same number of transmit antennas is used as a combination of transmit antennas.

6, _a total of 3 bits can be expressed through a combination of two active transmission antennas, where the total number ( M _t ) of transmission antennas is 5 and the number of active transmission antennas ( M _a ) is 2. And the power allocated to each active transmit antenna is inversely proportional to the number of active transmit antennas.

As described above, according to the above-described embodiments, the NOMA scheme using the power area distribution is allocated to some users based on the channel state and the channel gain of the user terminals, and the remaining users, The GSSK method using information is transmitted to the NOMA user, the super-coded signal is transmitted using the antennas activated by the GSSK antenna mapping to the NOMA user, and the GSSK user is transmitted with the specific antennas selected based on the antenna index information It is possible to reduce the signal interference by transmitting only the antenna index information to the cell outer user without limitation of the number of transmit antennas and to secure more users by improving the frequency efficiency than using only NOMA.

7 is a block diagram showing a configuration of a base station 10 according to another embodiment of the present invention.

7, the base station 10 may include a selection unit 12, a signal processing unit 14, and a transmission unit 16. In addition, the base station 10 may include other functional blocks, But is omitted to show only those parts necessary for understanding the operation according to the embodiment of the present invention.

The selector 12 can calculate the channel gain of each terminal in the channel. The terminals can be listed in the order of magnitude of the calculated channel gains, and a specific terminal 24 can be selected to allocate the GSSK scheme from the terminal having the smallest calculated channel gain.

The selection of a particular terminal to allocate the GSSK scheme may select an optimal number based on the state of the channel.

If the number of selected terminals increases, the step of superimposing coding of the NOMA becomes smaller. Therefore, the step of reducing the SIC of the terminal receiving the NOMA is reduced by the step of superimposing coding, which is reduced. However, it is preferable to consider the increase of the number of antennas and the complexity in consideration of the total.

The signal processing unit 14 allocates the transmission method (GSSK) using the antenna index information to the selected specific terminal 24 and allocates the multiplexing method using the power distribution to the terminals 21, 22, and 23 other than the selected specific terminal And can process signals according to each assigned method.

The transmitting unit 16 may transmit the superposed coded signal to the selected specific terminal 24 using the antennas activated by the antenna mapping.

The transmitting unit 16 can transmit signals to the terminals 21, 22, and 23 other than the selected specific terminal using specific antennas selected based on the antenna index information.

As shown in FIG. 6, the antenna mapping may use an antenna index mapping table in which all transmission antennas and active transmission antennas are mapped according to the GSSK scheme.

8 is a flowchart (S50) showing a specific example of a signal processing method of a base station according to another embodiment of the present invention.

Referring to FIG. 8, in step S52, the channel gain of each of the intra-channel terminals 21, 22, 23, and 24 can be calculated.

Generally, the channel gain may be higher for a terminal located close to the base station 10, unless there are other special obstacles.

In step S54, the terminal having the smallest channel gain can be selected based on the state of the channel.

For example, assuming that K users are uniformly distributed in the cell, the channel gain of each user is h ₁ > h ₂ > ... If h _{k -1 &} gt; h _k , the user UE (K) having the lowest channel gain can be regarded as a cell outer user and selected as a specific UE.

Alternatively, one or more more user terminals may be selected in order from a user terminal having the smallest channel gain to a specific terminal depending on the state of the channel. That is, the UE (K) is selected, and the next UE (K-1) is selected. In some cases, it may not be selected

In step S56, signal processing can be performed by allocating the GSSK scheme to the selected specific terminal and allocating the NOMA scheme to the remaining terminals.

In the above example, K-N users may use NOMA and the remaining N cell users may use GSSK. The N user terminals that have been allocated GSSK are subjected to signal processing using the spatial domain, and the K-N user terminals allocated with NOMA can distribute power using FTPA and perform signal processing using superposition coding.

In step S58, the terminal that has been assigned the NOMA scheme can transmit the superposed coded signal using the antennas activated by the GSSK antenna mapping.

Alternatively, a terminal having the GSSK scheme can transmit a signal using specific antennas selected based on the antenna index information.

The antenna mapping may use an antenna index mapping table in which all transmission antennas and active transmission antennas are mapped according to the GSSK scheme.

As described above, according to the embodiment of FIGS. 8 and 9, the NOMA scheme using the power area distribution is allocated to some users based on the channel state and the channel gains of the user terminals, and the remaining user, By allocating the GSSK scheme using the antenna index information, it is possible to reduce signal interference and secure more users by improving frequency efficiency than using only NOMA.

9 is a block diagram showing a configuration of a terminal 20 according to another embodiment of the present invention.

9, the user terminal 20 or 21 to 24) may include a determination unit 27, a first decompression unit 28, and a second decompression unit 29, 20 may further comprise other functional blocks, but are omitted for the sake of illustrating only the parts necessary for understanding the operation according to the embodiment of the present invention.

The determination unit 27 can determine whether the signal received from the base station is a signal superposed on the power domain or coded based on the antenna index information. When the signal is determined, information including the pilot signal received from the base station Can be judged on the basis of.

If the received signal is a superposition-coded signal in the power domain as a result of the determination, the first reconstructor 28 reconstructs the signal. If the received signal is a signal based on the antenna index information, the second reconstructor 29 ). ≪ / RTI >

The superposition coded signal may be a signal coded by the NOMA scheme and the coded signal based on the antenna index information may be a signal coded by the GSSK scheme,

The user terminal 20 according to the present invention includes a block (first reconstructing unit 28) for reconstructing a superposed coded signal in a power domain and a block for restoring a coded signal based on the antenna index information in the spatial domain Restoring unit 29).

The first reconstructing unit 28 reconstructs the superimposed coded signal in the power domain or the NOMA coded signal using the SIC.

The SIC of the first decompression unit 28 has the effect of reducing the number of steps of the SIC compared to a signal using only the conventional NOMA system when the NOMA system signal of the base station 10 according to the present invention is received. This is because it is not necessary to remove the signal of N stages because the GSSK scheme is used for N users having a small channel gain.

The second reconstructor 29 reconstructs the coded signal based on the antenna index information or the GSSK coded signal.

The second restoration unit may select an antenna index in the mapping table as shown in FIG. 6 and use it as information.

The conventional SSK signal is detected using a Maximal-Ratio Receive Combining (MRRC) detector, and a GSSK according to the present invention can detect a signal using MLD (Maximal Likelihood Detector). MLD has better BER performance than existing MRRC detector.

FIG. 10 is a flowchart (S70) showing a specific example of a signal processing method of a terminal according to another embodiment of the present invention.

Referring to FIG. 10, in step S72, information including a pilot signal can be received from a base station.

In step S74, based on the information including the pilot signal, it can be determined whether the signal received by the terminal 20 is a superposition-coded signal in the power domain or a signal coded based on the antenna index information.

For example, it can be judged whether the signal is a signal coded by the NOMA method or a signal coded by the GSSK method.

In step S76, if it is determined in step S74 that the received signal is a superposition-coded signal in the power domain or a signal coded in the NOMA scheme, the signal can be restored using the SIC.

Alternatively, if it is determined in step S74 that the received signal is a coded signal based on the antenna index information or a signal coded in the GSSK scheme, the antenna index can be selected from the mapping table and restored using the information.

As described above, according to the embodiment of FIGS. 9 and 10, the user terminal 20 which receives the signal of the base station 10 using the combination of the NOMA and the GSSK can use the SIC Is reduced by the number of GSSK users. In case of receiving GSSK, BER is improved by using MLD as a signal detector.

As described above, according to the present embodiments, the NOMA scheme using the power region allocation is allocated to some users based on the channel state and the channel gain of the user terminals, and the remaining users, And transmits the super-coded signal using the antennas activated by the GSSK antenna mapping to the NOMA user, and transmits the super-coded signal to the GSSK user using the specific antennas selected based on the antenna index information It is possible to implement a signal processing method, apparatus and base station combining NOMA and GSSK.

According to the signal processing method, apparatus, and base station that combine NOMA and GSSK provided in the embodiment, there is no restriction on the number of transmit antennas, and signal interference is reduced by transmitting only the antenna index information to the cell outer user, It is possible to improve the frequency efficiency and secure more users.

In the case of receiving the NOMA scheme, the user terminal receiving the signal of the base station combined with the NOMA and the GSSK decreases the number of steps of the SIC by the number of the GSSK users. When receiving the GSSK, the user terminal uses the MLD as the signal detector, Can be improved.

In addition, embodiments of the signal processing methods described above may be implemented in the form of computer program instructions that may be executed through various computer components. Furthermore, the computer program embodied may be recorded on a computer-readable recording medium. The recording medium mentioned above may be, but is not necessarily, a ROM, a magnetic disk or a compact disk, an optical disk, or the like.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, . Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

10: Base station
12:
14: Signal processor
16:
20, 21, 22, 23, 24: terminal
27:
28:
29:

Claims (19)

A selector for calculating a channel gain of each terminal in the channel and selecting a terminal from the terminal having the lowest calculated channel gain;
A signal processor for assigning a transmission scheme using antenna index information to the selected specific terminal and allocating a multiplexing scheme using power distribution to terminals other than the specific terminal; And
The base station transmits a superposition-coded signal using the antennas activated by the antenna mapping to the specific terminal, and transmits a signal to the terminals other than the specific terminal, using specific antennas selected based on the antenna index information. ;
.
The method according to claim 1,
Wherein the selection of the specific terminal is based on a state of the channel.
The method according to claim 1,
Wherein the transmission scheme using the antenna index information is a GSSK scheme.
The method according to claim 1,
Wherein the multiplexing scheme using the power allocation is a NOMA scheme.
The method according to claim 1,
Wherein the antenna mapping maps all transmission antennas and active transmission antennas according to a GSSK scheme.
A determination unit for determining whether the signal received from the base station is a signal superimposed on the power region or coded based on the antenna index information;
A first reconstructor for reconstructing the superimposed coded signal using SIC; And
A second reconstructing unit for reconstructing a coded signal based on the antenna index information;
.
The method according to claim 6,
Wherein the determination unit determines based on information including a pilot signal received from the base station.
The method according to claim 6,
Wherein the second restoration unit selects an antenna index from a mapping table and uses the selected antenna index as information.
The method according to claim 6,
And the second restoration unit detects a signal using the MLD.
The method according to claim 6,
Wherein the superposition coded signal is a signal coded by a NOMA method.
The method according to claim 6,
And the coded signal based on the antenna index information is a signal coded by a GSSK scheme.
A signal processing method of a base station,
Calculating a channel gain of each of the terminals in the channel and selecting a terminal from the terminal having the smallest calculated channel gain;
Allocating a transmission scheme using antenna index information to the selected specific terminal and assigning a multiplexing scheme using power allocation to terminals other than the specific terminal; And
Transmitting a superposition coded signal using the antennas activated by the antenna mapping to the specific terminal and transmitting a signal to the terminals other than the specific terminal using specific antennas selected based on the antenna index information;
/ RTI >
13. The method of claim 12,
Wherein the selection of the specific terminal is made based on the state of the channel.
13. The method of claim 12,
Wherein the antenna mapping maps all transmission antennas and active transmission antennas according to a GSSK scheme.
A signal processing method of a terminal,
Determining whether a signal received from a base station is a superposition coded signal in a power domain or a coded signal based on antenna index information;
If the received signal is a superposition coded signal, reconstructing it using SIC; And
If the received signal is a coded signal based on the antenna index information, selecting an antenna index from the mapping table and using the selected antenna index as information;
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16. The method of claim 15,
Wherein the determining step determines based on information including a pilot signal received from the base station.
16. The method of claim 15,
And wherein the coded signal based on the antenna index information detects a signal using MLD.
A computer program stored in a computer-readable medium for carrying out the method according to any one of claims 12 to 17.
A computer-readable recording medium on which a program for executing the method according to any one of claims 12 to 17 is recorded.

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