Anti-interference method and system

Provided is an anti-interference method and system. The anti-interference method includes: setting an orthogonal code division sequence according to a subcarrier position in a frequency domain of resource elements (REs) of a data channel in at least one sub-frame; and configuring transmitting frequency domain symbols of the REs by using the orthogonal code division sequence corresponding to the subcarrier position of the REs.

CROSS REFERENCE TO RELATED APPLICATIONS

This is the U.S. National Phase Application, filed under 35 U.S.C. 371, of International Patent Application No. PCT/CN2016/111472, filed on Dec. 22, 2016, which claims priority to Chinese patent application No. 201610217132.9 filed on Apr. 8, 2016, the entire disclosure of each of which is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to the technical field of mobile communications and, for example, relates to an anti-interference method and system.

BACKGROUND

The Long Term Evolution (LTE) system is a mobile broadband communication system and has been widely used. The LTE communication system may provide users with faster and more stable network services, having the characteristic of high receiving rate, high spectrum utilization, simple receiver and the like.

The downlink channel of the LTE system is orthogonal frequency division multiple access (OFDMA), and the uplink channel is single-carrier frequency-division multiple access (SC-FDMA). These two technologies essentially take use of the orthogonalization in frequency domain.

In the multi-node networking of the LTE wireless network, different points cannot operate at completely different frequencies. When the networking is implemented with one base station and one or more adjacent base stations operating at a same frequency, the data transmission rate at the edge of a cell decreases significantly due to the existence of co-channel interference. In response to this, LTE R11, R12 and subsequent evolution versions propose inter-cell interference coordination (ICIC), enhanced inter-cell interference coordination (eICIC), coordinated multiple points transmission or reception (COMP), and other interference coordination. ICIC reduces interference through coordination in frequency domain. eICIC reduces interference through coordination in time domain. COMP makes the cell and an adjacent cell simultaneously serve user equipment (UE) at the edge of the cell and the adjacent cell through a cooperation of multiple base stations. These methods need to perform a large number of signaling interactions through an X2 interface, have performance restricted by UE measurement or base station measurement. COMP has high requirements on delay and throughput for the X2 interface.

SUMMARY

The present disclosure provides an anti-interference method and system for improving anti-interference performance of uplink and downlink common data channels of the LTE system.

An anti-interference method is provided, including:

setting an orthogonal code division sequence according to a subcarrier position in a frequency domain of resource elements (REs) of a data channel in one or more sub-frames; and

configuring frequency domain transmitting symbols of the REs by using the orthogonal code division sequence corresponding to the subcarrier position of the REs.

In an embodiment, the number of the sub-frames has a value range of [1, 10].

In an embodiment, the number of the sub-frames is 1.

In an embodiment, the step of setting the orthogonal code division sequence includes: designing the orthogonal code division sequence with variable lengths, and setting the length of the orthogonal code division sequence to L; the orthogonal code division sequence being expressed as aL0, aL1, . . . , aLL−1.

In an embodiment, the length of the orthogonal code division sequence is the 2nth power of 2, where n is greater than or equal to 0.

In an embodiment, the step of configuring the frequency domain transmitting symbols of the REs by using the orthogonal code division sequence corresponding to the subcarrier position of the REs includes:

dividing available REs on each subcarrier into groups; and

configuring one or more frequency domain transmitting symbols of one or more available REs in each group by using the orthogonal code division sequence corresponding to the subcarrier position of the REs.

In an embodiment, the step of grouping the available REs on each subcarrier includes:

dividing the N available Res on one subcarrier in frequency domain into P groups, where the first group includes L1available REs, the second group includes L2available REs, . . . , and the Pth group includes Lpavailable REs.

In an embodiment, the method further includes that: for a physical downlink shared channel (PDSCH), when a reference signal (RS) of a Long Term Evolution (LTE) system is configured with 4 antenna ports, when no RS exists, the number N of the available REs in frequency domain is 14; and when the RS exists, the number N of the available REs in frequency domain is 8.

In an embodiment, the method further includes that: for a PDSCH, when an RS of the LTE system is configured with 2 antenna ports, when no RS exists, the number N of the available REs in frequency domain is 14; and when the RS exists, the number N of the available REs in frequency domain is 10.

In an embodiment, when N is 14, the step of dividing N available REs into P groups includes: setting P to 4 and adopting a 4, 4, 4, 2 four-segment spread spectrum, where a first group includes 4 available REs, a second group includes 4 available REs, a third group includes 4 available REs, and a fourth group includes 2 available REs.

In an embodiment, when N is 8, the step of dividing N available REs into P groups includes: setting P to 2 and adopting a 4, 4 two-segment spread spectrum, where a first group includes 4 available REs, and a second group includes 4 available REs.

In an embodiment, when N is 10, the step of dividing N available REs into P groups includes: setting P to 3 and adopting a 4, 4, 2 three-segment spread spectrum, where a first group includes 4 available REs, a second group includes 4 available REs, and a third group includes 2 available REs.

In an embodiment, for a physical uplink shared channel (PUSCH), when a demodulation reference signal (DMRS) exists, the number N of the available REs in frequency domain is 12; and when the DMRS and a sounding reference signal (SRS) exist, the number N of the available REs in frequency domain is 11.

In an embodiment, when N is 12, the step of dividing N available REs into P groups includes: setting P to 3 and adopting a 4, 4, 4 three-segment spread spectrum, where a first group includes 4 available REs, a second group includes 4 available REs, and a third group includes 4 available REs.

In an embodiment, when N is 11, the step of dividing N available REs into P groups includes: setting P to 3 and adopting a 4, 4, 2 three-segment spread spectrum, where a first group includes 4 available REs, a second group includes 4 available REs, a third group includes 2 available REs, and the last available RE is not included in the spread spectrum.

In an embodiment, the frequency domain transmitting symbols of the available REs in each group are configured by using the orthogonal code division sequence corresponding to the subcarrier position of the REs in the following manner:

a constellation symbol to be transmitted of a first group is expressed as x1, a constellation symbol to be transmitted of a second group is expressed as x2, . . . , and a constellation symbol to be transmitted of a Pth group is expressed as XP;

frequency domain transmitting symbols of available REs in the first group are aL10x1, aL11x1, . . . , aL1L1−1x1;

frequency domain transmitting symbols of available REs in the second group are a aL20x2, aL21x2, . . . , aL2L2−1x2;

and frequency domain transmitting symbols of available REs in the Pth group are aLp0xp, aLp1xp, . . . , and aLpLp−1xp.

The present disclosure further provides an anti-interference system, including a sequence setting unit and a configuration unit.

The sequence setting unit is configured to set an orthogonal code division sequence according to a subcarrier position in a frequency domain of REs of a data channel in one or more sub-frames.

The configuration unit is configured to configure frequency domain transmitting symbols of the REs by using the orthogonal code division sequence corresponding to the subcarrier position of the REs.

The present disclosure further provides a non-transient computer-readable storage medium, which is configured to store computer-executable instructions for executing the above-mentioned method.

The present disclosure further provides an anti-interference system, including:

at least one processor; and

a memory which is communicatively connected to the at least one processor;

the memory stores instructions which may be executed by the at least one processor, and the at least one processor executes the instructions to execute the above-mentioned method.

According to the present disclosure, the orthogonal code division multiplexing technology is introduced and the orthogonal code division sequence is used to perform spread spectrum on REs improving the anti-interference performance of uplink and downlink common data channels of the LTE system.

DETAILED DESCRIPTION

The present disclosure will be described in detail in conjunction with the drawings and the embodiments. If not in collision, the following embodiments and features thereof may be combined with each other.

A channel structure of a physical downlink shared channel (PDSCH) is shown inFIG. 1. The PDSCH has a reference signal (RS), a demodulation reference signal (DMRS) and the like.

Therefore, inFIG. 1, a horizontal axis represents a time domain, in units of orthogonal frequency division multiplexing (OFDM) symbols; and a vertical axis represents a frequency domain, in units of subcarriers. In a sub-frame, the multiple rows have different number of available resource elements (REs) at the same position in frequency domain (i.e., 1 OFDM symbol in time domain ( 1/14 ms) and1subcarrier (15 kHz) in frequency domain). For a normal cyclic prefix (CP) mode, when no RS exists, 14 available REs are provided; and when the RS exists, less than 14 available REs are provided. In the example illustrated inFIG. 1, 12 available REs are provided.

For the PDSCH and a physical uplink shared channel (PUSCH), the present disclosure provides an anti-interference method, which improves the anti-interference performance of uplink and downlink common data channels of the LTE system.

As shown inFIG. 2, a flowchart of an anti-interference method in a first embodiment of the present disclosure is provided.

In step S110, an orthogonal code division sequence is set according to a subcarrier position in a frequency domain of REs of a data channel in one or more sub-frame.

In step S120, frequency domain transmitting symbols of the REs are configured by using the orthogonal code division sequence corresponding to the subcarrier position of the REs.

In the above method, the orthogonal code division sequence may be set according to the subcarrier position in the frequency domain of the REs in one sub-frame or may be set according to the subcarrier positions in the frequency domain of the REs in multiple sub-frames at the same time. The number of the sub-frames has a value range of [1, 10], and the spread spectrum may be performed on a maximum of a same subcarrier in 10 sub-frames at the same time. The reason for the maximum of 10 is that one sub-frame has a length of 1 ms, and one radio frame of the LTE system has a length of 10 ms, that is, one radio frame includes 10 sub-frames.

In the following example, the number of sub-frames for spread spectrum is 1. Of course, the number of corresponding code division sequences increases when the number of sub-frames is larger than 1. The principle is similar and will not be described again.

The step S110in which the orthogonal code division sequence is set includes steps described below.

The orthogonal code division sequence with variable lengths is designed, the length of the orthogonal code division sequence is set to L. The orthogonal code division sequence is expressed as aL0, aL1, . . . , aLL−1. The length L of the orthogonal code division sequence is the 2nth power of 2, where n is greater than or equal to 0. The length L of the orthogonal code division sequence has such a value that the code division sequence is orthogonal, and the value of L may be 2 or 4.

FIG. 3shows how to configure frequency domain transmitting symbols of the REs by using the orthogonal code division sequence corresponding to the subcarrier position of the REs in step S120.

In step S210, available REs of each row are divided into groups. The REs of a same row occupy a same subcarrier.

In step S220, frequency domain transmitting symbols of the available REs in each group are configured by using the orthogonal code division sequence corresponding to the subcarrier position of the REs.

The step S210in which available REs of each row are divided into groups includes the steps described below.

The number of the available REs of a row in the frequency domain is expressed as N, and the N available REs are divided into P groups according to the requirement for high-layer transmission. Specifically, the first group includes L1available REs, the second group includes L2available REs, . . . , and the Pth group includes Lpavailable REs. The requirement for high-layer transmission may be the rate of high-layer transmission. The higher the rate of high-layer transmission is, the fewer available REs are contained in each group of REs.

The step S220in which frequency domain transmitting symbols of the available REs in each group are configured by using the orthogonal code division sequence corresponding to the subcarrier position of the REs is performed in a manner described below.

A constellation symbol to be transmitted of the first group is expressed as x1, a constellation symbol to be transmitted of the second group is expressed as x2, . . . , and a constellation symbol to be transmitted of the Pth group is expressed as XP.

In this case, frequency domain transmitting symbols of the available REs in the first group are aL10x1, aL11x1, . . . , aL1L1−1x1.

Frequency domain transmitting symbols of the available REs in the second group are a aL20x2, aL21x2, . . . , aL2L2−1x2.

Frequency domain transmitting symbols of the available REs in the Pth group are aLp0xp, aLp1xp, . . . , and aLpLp−1xp.

The above is the configuration of REs in a transmitter. In a corresponding receiver, signal modeling and demodulation may be performed. Signal modeling and demodulation in the receiver may be performed as described below.

The signal of the first group in the receiver may be modeled as
yL10=HL10aL10x1+NL10,
yL11=HL11aL11x1+NL11,
. . .
yL1L1−1=HL1L1−1aL1L1−1x1+NL1L1−1.

In the above formula, yL1L1−1is a receiving signal of an available RE numbered (L1−1) among L1available REs in the first group, HL1L1−1is a channel tap coefficient of a radio channel of the available RE numbered (L1−1) among the L1available REs in the first group, and NL10, NL11, . . . . , NL1L1−1are noise.

Since the L1available REs in the first group are located at the same frequency domain position, the channel tap coefficients of the radio channel HL10=HL11, . . . , =HL1L1−1may be considered to be approximately valid when correlation time of the channel caused by a Doppler frequency shift on the basis of the moving speed of the UE relative to a base station is greater than the length of one sub-frame, that is, 1 ms.

HL1, may be derived from channel estimation based on the downlink RS or the DMRS.

{circumflex over (x)}1is an estimate of x1.

A signal to interference plus noise ratio (SINR) is

L12⁢HL12NL12,
which is increased by a factor of (L12+1) relative to the related art in which the REs in frequency domain are configured without the orthogonal code division sequence.

As an embodiment of the present disclosure, the implementation of anti-interference in PDSCH is described here.

When the RS of the LTE is configured with four antenna ports, the structure of a downlink resource block (RB) is shown inFIG. 4. R0, R1, R2 and R3 are reference signals. Two cases may exist in each row of REs, i.e., 14 or 8 available REs. When no RS exists, 14 available REs are provided; and when the RS exists, 8 available REs are provided.

Therefore, the signaling of the physical downlink control channel (PDCCH) may completely indicate the form of used code sequence in the two cases.

It is assumed that for the case of 14 available REs, a code sequence with a length L of 4 and a code sequence with a length L of 2 are used for spread spectrum. The 14 available REs may be divided into 4 groups, that is, P is 4. The first three groups each have a length L of 4, and the fourth group has a length L of 2. The frequency domain transmitting symbols of the REs configured by using the orthogonal code division sequences corresponding to the subcarrier position of the REs are configured as shown inFIG. 5. It is assumed that for the case of 8 available REs, a code sequence with a length L of 4 is used for spread spectrum, and the available Res are divided two groups each having a length of 4. The signaling information may be constructed in a following form as listed in Table 1.

In implementation, an extension field may be added to a digital copyright identifier (DCI) signaling of the LTE system. For DCI, protocol 36.212 can be referred to, and the extension field is added at the end of the DCI field.

TABLE 1DCI signalingTotal length N of REs1110Code sequence index 100Code sequence index 200Code sequence index 300Code sequence index 40Total length N of REs1000Code sequence index 101Code sequence index 201

For a row with a total length 14 of the available REs, the row is divided into 4 segments for spread spectrum and the spread spectrum codes are 4, 4, 4, 2, respectively. The length of the spread spectrum code sequence is followed by the index number of the code sequence. The index and the sequence table for the orthogonal code sequences with a length of 4 are listed in Table 2.

TABLE 2Orthogonal code sequences with a length of 4Code sequencebinary indexOrthogonal code sequence with a length of 4001111011−11−11011−1−1111−1−11

The o index and the sequence table for the orthogonal code sequences with a length of 2 are listed in Table 3.

TABLE 3Orthogonal code sequence with a length of 2Code sequenceOrthogonal code sequencebinary indexwith a length of 201111−1

According to the signaling indications inFIG. 4and Table 1, spread spectrum is performed with a code sequence (1, −1, 1, −1) for the 0th, 3rd, 6th and 9th rows of the RB, and spread spectrum is performed with code sequences (1, 1, 1, 1) and (1, 1) for remaining rows.

Only the spread spectrum mapping diagrams of the 0th row and 1st row are given here, and the extension of the other rows follows the same principle. The mapping of the 0th row is shown inFIG. 6. R0, R1, R2, and R3 are reference signals, and the total length of the available REs is 8. In the positions other than the reference signals, spectrum spread is performed using the code sequence (1, −1, 1, −1), and 8 REs requires to adopt two sets of the code sequence.

The mapping of the 1st row is shown inFIG. 7. This row has no reference signal, the total length of the available REs is 14, and the spread spectrum is performed using three sets of code sequence (1, 1, 1, 1) and one set of code sequence (1, 1).

When the RS of the LTE is configured with two antenna ports, the structure of a downlink RB is shown inFIG. 1, where two cases may exist in each row of REs, 14 or 10 available REs. When no RS exists, 14 available REs are provided; and when RSs exist, 10 available REs are provided.

When N is 14, the principle of the spectrum spreading is the same as the principle when the RS of the LTE system is configured with four antenna ports, and will not be described again.

When N is 10, according to the need for high-layer transmission, the division of the N available REs into P groups is performed in the following manner.

P is set to 3, and a 4, 4, 2 three-segment spread spectrum is adopted. The first group includes 4 available REs, the second group includes 4 available REs, and the third group includes 2 available REs. A mapping diagram for configuring frequency domain transmitting symbols of the REs by using the orthogonal code division sequences is shown inFIG. 8.

As an embodiment of the present disclosure, the implementation of anti-interference in PUSCH is described below.

As shown inFIG. 9, for a RB in which a user is located, when a DMRS exists, the number N of the available REs in frequency domain is 12; and when the DMRS and a sounding reference signal (SRS) exist, the number N of the available REs in frequency domain is 11.

When N is 12, according to a need for high-layer transmission, the division of the N available REs into P groups is performed in the following manner.

P is set to 3, and a 4, 4, 4 three-segment spread spectrum is adopted. The first group includes 4 available REs, the second group includes 4 available REs, and the third group includes 4 available REs. A mapping diagram for configuring frequency domain transmitting symbols of the REs by using the orthogonal code division sequences is shown inFIG. 10.

For a row with a total length of the available REs being 11, the raw is divided into 3 segments for performing spread spectrum respectively. The length of the spread spectrum code sequences are 4, 4, 2, respectively. The first group includes 4 available REs, the second group includes 4 available REs, and the third group includes 2 available REs. A mapping diagram for configuring frequency domain transmitting symbols of the REs by using the orthogonal code division sequences is shown inFIG. 11. The length of the spread spectrum code sequence is followed by the index number of the code sequence. The DCI format is listed in Table 4.

TABLE 4DCI signalingTotal length N of REs1011Code sequence index 100Code sequence index 200Code sequence index 30

The orthogonal code sequence index and the sequence table for the orthogonal code sequences with a length of 4 are listed in Table 2.

The orthogonal code sequence index and the sequence table for the orthogonal code sequences with a length of 2 are listed in Table 3.

The allocation of REs is performed in the order from left to right.

For other spread spectrum mechanisms, reference may be made to the implementation of anti-interference in the downlink channel PDSCH.

The present disclosure further provides an anti-interference system as shown inFIG. 12. The anti-interference system includes an orthogonal code division sequence setting unit 1 and a configuration unit 2.

The orthogonal code division sequence setting unit 1 is configured to set an orthogonal code division sequence according to a subcarrier position in a frequency domain of REs of REs in one or more sub-frame.

The configuration unit 2 is configured to configure frequency domain transmitting symbols of the REs by using the orthogonal code division sequence corresponding to the subcarrier position of the REs.

In the present disclosure, the orthogonal code division technology is introduced and the orthogonal code division sequence is used to perform spread spectrum on REs, improving the anti-interference performance of uplink and downlink common data channels of the LTE system.

The present disclosure further provides a non-transient computer-readable storage medium, which is configured to store computer-executable instructions for executing the method in any embodiment described above.

The present disclosure further provides a structural diagram of hardware of the anti-interference system. Referring toFIG. 13, the system includes at least one processor30and a memory. In the example as shown inFIG. 13, one processor30is included. The system may further include a communication interface32and a bus33.

The processor30, the communication interface32and the memory31may communicate with each other via the bus33. The communication interface32may be used for information transmission. The processor30may call logic instructions in the memory31to execute the method described in the above-mentioned embodiments.

In addition, the logic instructions in the memory31may be implemented in the form of a software function unit and, when sold or used as an independent product, may be stored in a computer-readable storage medium.

As a computer-readable storage medium, the memory31may be used for storing software programs and computer-executable programs, such as program instructions or modules corresponding to the method in embodiments of the present disclosure. The processor30runs the software programs, instructions or modules stored in the memory31to execute function applications and data processing, that is, to implement the anti-interference method described in the above method embodiments.

The memory31may include a program storage region and a data storage region, where the program storage region may store an operating system and an application program required by at least one function; and the data storage region may store data created depending on use of a terminal device. In addition, the memory31may include a high-speed random access memory, and may further include a non-volatile memory.

The present disclosure may be embodied in the form of a software product that is stored in a storage medium and includes one or more instructions for enabling a computer device (which may be a personal computer, server, network device, etc.) to execute all or part of the steps of the method provided in embodiments of the present disclosure. The foregoing storage medium may be a non-transient storage medium, such as a U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), magnetic disk, optical disk or other medium that may store program codes, or may be a transient storage medium.

INDUSTRIAL APPLICABILITY

The anti-interference method and system provided by the present disclosure improve the anti-interference performance of uplink and downlink common data channels of the LTE system.