Channel interference mitigation method, apparatus, and system for performing channel compensation to obtain another channel according to received adjustment parameters

Embodiments of the present invention provide a data transmission processing method, apparatus, and system. The method includes: receiving, by a first base station, an adjustment parameter transmitted by a terminal, where the adjustment parameter is obtained by the terminal according to reference signals separately transmitted by the first base station and a second base station; performing, by the first base station and according to the adjustment parameter, channel compensation on a first channel between the first base station and the terminal to obtain a second channel; and transmitting, by the first base station, a first signal over the second channel to the terminal, so that the terminal obtains the first signal from a mixed signal of the first signal and a second signal that is transmitted by the second base station.

TECHNICAL FIELD

The present invention relates to the field of communications technologies, and in particular, to a data transmission processing method, apparatus, and system.

BACKGROUND

A heterogeneous network (Heterogeneous Network, HetNet for short) is capable of effectively enhancing throughput of a current network system, and has become a focus of discussion in the 3GPP standard.

FIG. 1is a schematic diagram of a heterogeneous network in the prior art. As shown inFIG. 1, the HetNet may include a macro base station (Macro eNB) and multiple pico base stations (Pico eNB). The Macro eNB covers a large macrocell (macrocell). In a hot spot area (that is, an area with a high communication demand), multiple Pico eNBs are deployed as required. Each Pico eNB covers a small picocell (picocell). Each picocells are far from another. Therefore, the multiple Pico eNBs may use a same spectrum without the need of considering a problem of interference on each other. From the perspective of the whole macrocell, one spectrum may be reused by multiple Pico eNBs, so that spectrum utilization rate is high and system throughput is high.

However, in the HetNet, the transmit power of the Macro eNB is generally over 10 dB (dB) higher than the transmit power of the Pico eNB. Therefore, for a Pico eNB closer to the Macro eNB, when the Pico eNB uses a same downlink spectrum as the Macro eNB, a terminal corresponding to the Pico eNB, when receiving signals transmitted by the Pico eNB, may suffer strong interference caused by a signal transmitted by the Macro eNB. To overcome the interference, in the prior art, the downlink spectrum used by the Pico eNB is generally controlled, so that the downlink spectrum used by the Pico eNB different from that used by the Macro eNB. Consequently, the Macro eNB and the Pico eNB are capable of using only part of spectrum resources, which thereby leading to low system throughput.

SUMMARY OF THE INVENTION

Embodiments of the present invention provides a data transmission processing method, apparatus, and system, so that a macro base station and a pico base station in a heterogeneous network can use a same spectrum, and system throughput is improved.

An embodiment of the present invention provides a data transmission processing method, where the method includes receiving, by a first base station, an adjustment parameter transmitted by a terminal, where the adjustment parameter is obtained by the terminal according to reference signals separately transmitted by the first base station and a second base station, performing, by the first base station and according to the adjustment parameter, channel compensation on a first channel between the first base station and the terminal to obtain a second channel, and transmitting, by the first base station, a first signal over the second channel to the terminal, so that the terminal obtains the first signal from a mixed signal of the first signal and a second signal that is transmitted by the second base station, where the first signal and the second signal are transmitted by the first base station and the second base station using a same spectrum to the terminal, respectively.

An embodiment of the present invention provides a data transmission processing method, where the method includes obtaining, by a terminal, an adjustment parameter according to reference signals separately transmitted by a first base station and a second base station, transmitting, by the terminal, the adjustment parameter to the first base station, so that the first base station performs, according to the adjustment parameter, channel compensation on a first channel between the first base station and the terminal to obtain a second channel, receiving, by the terminal, a mixed signal of a first signal transmitted by the first base station over the second channel and a second signal transmitted by the second base station, and obtaining, by the terminal, the first signal from the mixed signal; where the first signal and the second signal are transmitted by the first base station and the second base station using a same spectrum to the terminal, respectively.

An embodiment of the present invention provides a base station, including a receiving module, configured to receive an adjustment parameter obtained by a terminal according to reference signals separately transmitted by a first base station and a second base station; where the base station is the first base station, a channel compensating module, configured to perform, according to the adjustment parameter, channel compensation on a first channel between the first base station and the terminal to obtain a second channel, and a transmitting module, configured to transmit a first signal over the second channel to the terminal so that the terminal obtains the first signal from a mixed signal of the first signal and a second signal that is transmitted by the second base station; where the first signal and the second signal are transmitted by the first base station and the second base station using a same spectrum to the terminal, respectively.

An embodiment of the present invention provides a terminal, including an obtaining module, configured to obtain an adjustment parameter according to reference signals separately transmitted by a first base station and a second base station, a transmitting module, configured to transmit the adjustment parameter to the first base station, so that the first base station performs, according to the adjustment parameter, channel compensation on a first channel between the first base station and the terminal to obtain a second channel, a receiving module, configured to receive a mixed signal of a first signal transmitted by the first base station over the second channel and a second signal transmitted by the second base station, and a processing module, configured to obtain the first signal from the mixed signal; where the first signal and the second signal are transmitted by the first base station and the second base station using a same spectrum to the terminal, respectively.

An embodiment of the present invention provides a data transmission processing system, including any base station provided in the embodiments of the present invention, and any terminal provided in the embodiments of the present invention.

In the data transmission processing method, apparatus, and system provided in the embodiments of the present invention, the terminal obtains the adjustment parameter according the reference signals of the first base station and the second base station. The first base station performs, according to the adjustment parameter obtained by the terminal, channel compensation on the first channel between the first base station and the terminal to obtain the second channel, and transmits the first signal to the terminal over the second channel so that the terminal may obtain the first signal from the mixed signal of the first signal and the second signal that is transmitted by the second base station using the same spectrum as that of the first signal. In this way, the first base station and the second base station may use the same spectrum to transmit signals, which improves system throughput.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In order to make objectives, technical solutions, and advantages of the present invention clearer, technical solutions according to embodiments of the present invention are clearly and completely described in the following with reference to the accompanying drawings. Apparently, the embodiments in the description are only part rather than all of the embodiments of the present invention. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

FIG. 2is a flowchart of a first embodiment of a data transmission processing method according to the present invention. As shown inFIG. 2, in this embodiment, a first base station is taken as an execution body. The method includes the following steps.

Step201: The first base station receives an adjustment parameter transmitted by a terminal, where the adjustment parameter is obtained by the terminal according to reference signals separately transmitted by the first base station and a second base station.

In application scenarios of embodiments of the present invention, the terminal (Terminal, UE for short) corresponds to the first base station, the first base station and the second base station transmit downlink signals using a same spectrum, the strength of a downlink signal transmitted by the second base station is greater than that of a downlink signal transmitted by the first base station, and frame structures of the downlink signals transmitted by the first base station and the second base station are synchronized. When receiving a signal transmitted by the first base station, the UE simultaneously receives a signal transmitted by the second base station.

The UE performs pilot detection on the reference signals of the first base station and the second base station, and detects a channel between the UE and the first base station and a channel between the UE and the second base station. To eliminate interference from the signal transmitted by the second base station, the UE obtains the adjustment parameter according to the detected channels, and then transmits the adjustment parameter to the first base station so that the first base station performs pre-compensation on a first channel between the first base station and the UE.

Step202: The first base station performs, according to the adjustment parameter, channel compensation on the first channel between the first base station and the terminal to obtain a second channel.

After receiving the adjustment parameter transmitted by the UE, the first base station performs, according to the adjustment parameter, pre-compensation on the first channel between the first base station and the UE to obtain the second channel. A phase of the first channel and a modulus of the first channel may be adjusted according to the adjustment parameter, or a channel matrix may be pre-rotated according to the adjustment parameter, so as to perform pre-compensation on the first channel.

Step203: The first base station transmits the first signal to the terminal over the second channel so that the terminal obtains the first signal from a mixed signal including the first signal and a second signal that is transmitted by the second base station.

The first signal and the second signal are transmitted by the first base station and the second base station using the same spectrum to the terminal, respectively; and the strength of the second signal is greater than that of the first signal.

After performing pre-compensation on the first channel and obtaining the second channel, the first base station transmits the first signal to the UE over the second channel; and meanwhile, the second base station transmits the second signal. The mixed signal received by the UE includes the first signal and the second signal. The first base station performs pre-compensation on the channel, so that the UE is capable of separating the first signal and the second signal in the mixed signal to obtain the first signal. For example, the UE may obtain the first signal from a constellation diagram corresponding to the mixed signal.

In the embodiment of the present invention, the terminal obtains the adjustment parameter according the reference signals of the first base station and the second base station. The first base station performs, according to the adjustment parameter obtained by the terminal, pre-compensation on the first channel between the first base station and the terminal to obtain the second channel, and transmits the first signal to the terminal over the second channel so that the terminal is capable of obtaining the first signal from the mixed signal of the first signal and the second signal that is transmitted by the second base station using the same spectrum as that of the first signal. In this way, the first base station and the second base station can use the same spectrum to transmit signals, which improves system throughput.

FIG. 3is a flowchart of a second embodiment of a data transmission processing method according to the present invention. As shown inFIG. 3, in this embodiment, a terminal is taken as an execution body. The method includes the following steps.

Step301: A terminal obtains an adjustment parameter according to reference signals separately transmitted by a first base station and a second base station.

This embodiment corresponds to the first method embodiment shown inFIG. 2. For the application scenario and related details, reference is made to the description in the first method embodiment.

The UE performs pilot detection on the reference signals of the first base station and the second base station, and detects a channel between the UE and the first base station and a channel between the UE and the second base station. To eliminate interference from a signal transmitted by the second base station, the UE obtains the adjustment parameter according to the detected channels so that the first base station performs pre-compensation on a first channel between the first base station and the UE.

Step302: The terminal transmits the adjustment parameter to the first base station, so that the first base station performs, according to the adjustment parameter, channel compensation on the first channel between the first base station and the terminal to obtain a second channel.

The UE transmits the obtained an adjustment parameter to the first base station, so that the first base station, after receiving the adjustment parameter transmitted by the UE, performs, according to the adjustment parameter, pre-compensation on the first channel between the first base station and the UE to obtain the second channel. A phase of the first channel and a modulus of the first channel may be adjusted according to the adjustment parameter, or a channel matrix may be pre-rotated according to the adjustment parameter, so as to perform pre-compensation on the first channel.

Step303: The terminal receives a mixed signal of a first signal transmitted by the first base station over the second channel and a second signal transmitted by the second base station.

After performing pre-compensation on the first channel to obtain the second channel, the first base station transmits the first signal to the UE over the second channel; and meanwhile the second base station transmits the second signal. The mixed signal received by the UE includes the first signal and the second signal. The first signal and the second signal are separately transmitted by the first base station and the second base station using a same spectrum to the terminal; and the strength of the second signal is greater than that of the first signal.

Step304: The terminal obtains the first signal from the mixed signal.

The first base station performs pre-compensation on the channel so that the UE is capable of separating the first signal and the second signal in the mixed signal to obtain the first signal. For example, the UE may obtain the first signal from a constellation diagram corresponding to the mixed signal.

In the embodiment of the present invention, the terminal obtains the adjustment parameter according the reference signals of the first base station and the second base station, and transmits the adjustment parameter to the first base station, so that the first base station performs, according to the adjustment parameter obtained by the terminal, pre-compensation on the first channel between the first base station and the terminal to obtain the second channel, and first base station transmits the first signal to the terminal over the second channel, The terminal obtains the first signal from the mixed signal of the first signal and the second signal that is transmitted by the second base station using the same spectrum as that of the first signal. In this way, the first base station and the second base station can use the same spectrum to transmit signals, which improves system throughput.

The embodiment of the present invention may be applied in HetNet architecture. The HetNet may include a macro base station (Macro eNB) and multiple pico base stations (Pico eNBs). The UE in the embodiment of the present invention may be a Pico UE of a Pico eNB. The embodiment of the present invention is applicable to a process that the Pico eNB transmits data to multiple Pico UEs using a single-antenna or multi-antenna technology. The following embodiments use only a processing process of a Pico UE and pre-processing by the Pico eNB for the Pico UE as examples for illustration. In the following embodiments, the Pico UE is indicated by PUE1, the Pico eNB is indicated by PeNB1, and the Macro eNB is indicated by MeNB1. The following separately describes scenarios where the Pico eNB uses a single antenna and multiple antennas.

FIG. 4is a flowchart of a third embodiment of a data transmission processing method according to the present invention. This embodiment is applied in a scenario of a single antenna. As shown inFIG. 4, the method includes the following steps.

Step401: A terminal obtains an adjustment parameter according to reference signals separately transmitted by a first base station and a second base station. The adjustment parameter includes A1and B1, where A1=ang(H1m)−ang(H1p), and

In this embodiment, the first base station may be PeNB1, the second base station may be MeNB1, and the terminal may be PUE1. PeNB1and MeNB1use a same spectrum to transmit downlink signals. In this embodiment, MeNB1transmits a single data stream and PUE1has only one antenna.

H1pindicates a first channel between PeNB1and PUE1;

|H1p| Indicates a modulus of the first channel between PeNB1and PUE1;

ang (H1p) indicates a phase of the first channel between PeNB1and PUE1;

|H1m| indicates a modulus of the channel between MeNB1and PUE1; and

ang(H1m) indicates a phase of the channel between MeNB1and PUE1; and γ is a constant greater than 1.

Step402: The first base station performs, according to formula 1, channel compensation on the first channel to obtain a second channel. Formula 1 is H1p′=H1p×eiA1×B1, where H1p′indicates the second channel.

PeNB1performs channel compensation on the first channel according to formula 1, and adjusts the modulus of the first channel and the phase of the first channel to obtain the second channel.

After PeNB1obtains the second channel, PUE1may obtain the second channel from the reference signal of PeNB1. PUE1receives a modulation mode of the PeNB1transmitted by PeNB1and a modulation mode of MeNB1, where the modulation mode of MeNB1may be transmitted to PUE1by MeNB1, or may also be transmitted to PUE1by PeNB1after PeNB1obtains the modulation mode from MeNB1. PUE1may also obtain a third channel from the reference signal of MeNB1. The third channel is a channel between MeNB1and PUE1. PUE1normalizes the modulation modes of PeNB1and MeNB1, and the signals of the second channel and the third channel, to generate a constellation diagram after superposition of signals transmitted by PeNB1and MeNB1, that is, the constellation diagram is obtained by superposing a constellation diagram of PeNB1and a constellation diagram of MeNB1. The normalization process may be: for example, dividing a signal received by PUE1by channel H1m. That is, according to the modulation modes indicating PeNB1and MeNB1, and to-be-normalized channel information of the second channel and the third channel, PUE1generates a constellation diagram after superposition of signals transmitted by PeNB1and MeNB1, that is, the constellation diagram is obtained by superposing a constellation diagram of PeNB1and a constellation diagram of MeNB1. The normalization process may be: for example, dividing a signal received by PUE1by channel H1m.

Step403: The first base station transmits a first signal to the terminal over the second channel.

PeNB1transmits a signal to PUE1over the second channel. The signal is called the first signal.

Step404: The terminal receives a mixed signal transmitted by the first base station and the second base station. The mixed signal includes the first signal transmitted by the first base station and the second signal transmitted by the second base station.

PUE1receives the mixed signal. The mixed signal includes the first signal and the second signal that are transmitted by MeNB1and PeNB1.

Step405: The terminal obtains the first signal from the mixed signal according to a minimum distance principle, the mixed signal, and a constellation diagram corresponding to the mixed signal.

The constellation diagram that is generated by PUE1after superposition of signals transmitted by PeNB1and MeNB1is the constellation diagram corresponding to the mixed signal.

If step401and the pre-compensation operation on the first channel in step402are not performed, an error probability may be high when the first signal is obtained according to the superposed constellation diagram. This is because of the difference between the second channel and the third channel. In the superposed constellation diagram, the first signal is rotated to a certain angle relative to the second signal, and has different relative amplitude. Specifically, there is an angle between the constellation diagram of PeNB1and the constellation diagram of MeNB1. The angle may shorten the minimum distance between signals of the superposed constellation diagram, and increase an error probability of detection. Due to uncertainty of small-scale channel attenuation, the constellation diagram of PeNB1may have too great amplitude so that the constellation diagram of PeNB1may overlap the constellation diagram obtained through superposition of multiple constellation diagrams of MeNB1. Consequently, an error probability is high when demodulation is performed according to the minimum distance principle.

In an embodiment, the angle between the constellation diagram of PeNB1and the constellation diagram of MeNB1is a random angle. The angle may shorten the minimum distance between signals of the superposed constellation diagram, and increase the error probability of detection. Due to the uncertainty of the small-scale channel attenuation, a small distance between signals may occur in the constellation diagram obtained through superposition of the constellation diagram of PeNB1and the constellation diagram of MeNB1. Consequently, the error probability is high when demodulation is performed according to the minimum distance principle.

Therefore, in the embodiment of the present invention, the first signal transmitted by PeNB1is pre-processed, that is, PeNB1performs pre-compensation on the first channel, so that the first signal is pre-processed before being transmitted. Thereby, the phase and amplitude of the constellation diagram of PeNB1are adjusted so that PUE1can accurately obtain the first signal from the superposed constellation diagram. Experiments prove that, to ensure that PUE1can accurately obtain the first signal from the superposed constellation diagram, a preferable phase is a phase ensuring that the angle formed by the constellation diagram of PeNB1and the constellation diagram of MeNB1is a multiple of 90°, and a preferable amplitude is an amplitude ensuring that the amplitude of the constellation diagram of PeNB1is half of the amplitude of the constellation diagram of MeNB1. Through the method provided in the embodiment of the present invention, pre-compensation is performed on the first channel. According to the speed of channel change, the value of γ is adaptively adjusted, so that the constellation diagram of PeNB1meets the foregoing requirements of the phase and amplitude as much as possible. A channel changes along with time, and an adjustment parameter is calculated according to a channel at current time. However, when an adjusted channel is used to transmit data, an optimal adjustment parameter may be changed. Therefore, in the method provided in the embodiment of the present invention, the value of γ is adjusted so that an adjusted constellation diagram meets the foregoing requirements. When the channel change slowly, γ=2 preferably.

FIG. 5is a constellation diagram after superposition according to an embodiment of the present invention. As shown in the constellation diagram inFIG. 5, PeNB1and MeNB1both adopts the quadrature phase shift keying (Quadrature Phase Shift Keying, QPSK for short) modulation mode to transmit downlink signals. Black dots correspond to signal transmitted by MeNB1, and white dots correspond to superposition of signal transmitted by PeNB1and the signal transmitted by MeNB1. InFIG. 5,00,01,10, and11indicate the data that corresponds, before the signal is modulated by PeNB1or MeNB1, to the signal transmitted by PeNB1or MeNB1.

PUE1finds, according to the minimum distance principle and in the constellation diagram after superposition, a point closest to a received mixed signal, so as to separately detect a first signal and a second signal. For example, if the received mixed signal is closest to white dot10superposed with black dot00, it may be detected that data corresponding to the first signal is10and data corresponding to the second signal is00. After the first signal is detected, PUE1demodulates and decodes the first signal.

In the embodiment of the present invention, the terminal obtains the adjustment parameter according the reference signals of the first base station and the second base station, the first base station performs pre-compensation on the first channel between the first base station and the terminal according to the adjustment parameter obtained by the terminal to obtain the second channel, and transmits the first signal to the terminal over the second channel, and the second base station transmits the second signal using the same spectrum as the first base station. The first base station performs pre-compensation on the first channel, so that the first signal and the second signal are superposed in an one-to-one manner, and the phase and amplitude of each superposed constellation diagram are adjusted. Thereby, the terminal can detect the first signal and the second signal from the constellation diagram corresponding to the mixed signal that includes the first signal and the second signal. In this way, the first base station and the second base station can use the same spectrum to transmit signals, which improves system throughput.

FIG. 6is a flowchart of a fourth embodiment of a data transmission processing method according to the present invention. This embodiment is applied in a scenario of multiple antennas. As shown inFIG. 6, the method includes the following steps.

Step601: A terminal obtains an adjustment parameter according to reference signals separately transmitted by a first base station and a second base station. The adjustment parameter includes P, where P=A2·H2m.

In this embodiment, the first base station may be PeNB1, the second base station may be MeNB1, and the terminal may be PUE1. PeNB1and MeNB1use a same spectrum to transmit downlink signals.

An application scenario of this embodiment may be: MeNB1transmits M data streams, PeNB1transmits L data streams to PUE1, and PUE1has N antennas, where M≦N, L≦N, M+L>N. It is defined that K=M+L−N. The foregoing scenario may be equivalent to a case that MeNB1transmits K data streams, PeNB1transmits K data streams to PUE1, and PUE1has K receiving antennas. The detailed reasons for this is as follows: Because PUE1has N receiving antennas (that is, capable of differentiating N data streams), in the L data streams transmitted by PeNB1, N−M data streams may be received without interference, and the remaining K=L−(N−M) data streams may suffered interference of MeNB1; PUE1may eliminate L−K data streams of MeNB1through simple design of a receiver, so as to obtain a signal obtained through superposition of K data streams of MeNB1and K data streams of PeNB1. In addition, if MeNB1adopts a space time coding (Space Time Coding) manner for transmission, the foregoing idea may also be adopted for equivalence. The following describes in detail a scenario after equivalence. In this scenario, the terminal, the first base station, and the second base station include K antennas each and K>1.

In the adjustment parameter P:

H2m=(H2a,bm)|α=1,2 . . . , K;b=1,2, . . . , K, where H2mindicates a channel matrix from the second base station to the terminal, H2a,bmindicates an element in row a, column b in the channel matrix H2m, H2a,bmindicates a channel from a bthantenna of the second base station to an athantenna of the terminal; and

H2p=(H2a,bp)|α=1,2, . . . , K;b=1,2, . . . , K, where H2pindicates a channel matrix corresponding to a first channel from the first base station to the terminal, H2a,bpindicates an element in row a, column b in the channel matrix H2p, and H2a,bpindicates a first channel from the bthantenna of the first base station to the athantenna of the terminal.

For A2, there are two construction methods.

One is a construction method based on zero-forcing (Zero-forcing): A2=α(H2p)−1, where a coefficient α is used to ensure that a sum of elements on a diagonal line after matrix P is multiplied by a conjugate transpose of matrix P is smaller than or equal to 1, that is, tr(PP*)≦1; and P* indicates the conjugate transpose of matrix P.

The other is a construction method based on a minimum mean square error (Minimum mean square error, MMSE for short): A2=α(H2p)*(H2p(H2p)*+βI)−1, where I indicates a unit matrix, and β indicates power of noise on each antenna of the terminal. (H2p)* indicates the conjugate transpose of matrix H2p; and the coefficient α is the same as above.

Step602: The first base station performs, according to formula 2, channel compensation on the first channel to obtain a second channel. Formula 2 is H2p′=H2pP, where H2p′indicates a channel matrix corresponding to the second channel.

Before PeNB1obtains the second channel and transmits a signal over the second channel, PUE1may obtain the second channel from a reference signal of PeNB1. PUE1receives a modulation mode of the PeNB1transmitted by PeNB1and a modulation mode of MeNB1. The modulation mode of MeNB1may be transmitted to PUE1by MeNB1, or may also be transmitted to PUE1by PeNB1after PeNB1obtains the modulation mode from MeNB1. PUE1may also obtain a third channel from a reference signal of MeNB1. PUE1generates, according to the modulation modes of PeNB1and MeNB1, the second channel and the third channel, a constellation diagram after superposition of signals transmitted by PeNB1and MeNB1. That is, according to the modulation modes indicating PeNB1and MeNB1, and to-be-normalized channel information of the second channel and the third channel, PUE1generates a constellation diagram after superposition of signals transmitted by PeNB1and MeNB1. For detailed description, reference is made to the description in the second method embodiment.

Step603: The first base station transmits a first signal to the terminal over the second channel.

PeNB1transmits a signal to PUE1over the second channel. The signal is called the first signal.

Step604: The terminal receives a mixed signal transmitted by the first base station and the second base station. The mixed signal includes the first signal transmitted by the first base station and the second signal transmitted by the second base station.

Step605: The terminal processes the mixed signal into a third signal according to formula 3, where formula 3 is {tilde over (Y)}=BY.

PUE1performs left-multiplication on a signal received on each antenna and matrix B.

Y=[y1, y2, . . . , yK]T, indicating a signal vector of the received mixed signal, where yiindicates a symbol received by PUE1on an ithantenna; and {tilde over (Y)} indicates a signal vector of the third signal.

Theoretically, the mixed signal may be indicated by: Y=H2mU2m+H2pPU2p+Z. U2p=[U1P, u2P, . . . , uKP]T, where uiPrepresents a modulation symbol of an ithdata stream transmitted by PeNB1to PUE1, and U2mindicates a signal vector of the second signal; U2m=[u1m, u2m, . . . , uKm]T, where uimindicates a modulation symbol of an data stream transmitted by MeNB1and Z indicates a noise vector.

For B, there are two construction methods: One is a construction method based on Zero-forcing, B=(H2m)−1; and the other is a construction method based on an MMSE, B=((H2m)*H2m+βI)−1(H2m)*.

Step606: The terminal obtains the second signal from the third signal according to a minimum distance principle, the third signal, and a constellation diagram corresponding to the third signal.

After step605, each element in the vector {tilde over (Y)} of the third signal is a superposition of one first signal of PeNB1and one second signal of MeNB1. In this embodiment, PUE1may generate K constellation diagrams after superposition, according to the modulation mode of PeNB1, the modulation mode of MeNB1, the second channel, and the third channel. K elements in the vector {tilde over (Y)} are corresponding to the K constellation diagrams after superposition one to one. PUE1may detect, according to the minimum distance principle, each element in the vector {tilde over (Y)}, and a constellation diagram that is after superposition and corresponds to the element, data that corresponds, before the second signal is modulated by MeNB1, to the second signal transmitted by MeNB1(for a specific detection process, reference is made to the description in step405in the second embodiment, which is not detailed here), so as to obtain the signal vector of the second signal, marked as Ũ2m. The K constellation diagrams after superposition are constellation diagrams corresponding to the third signal.

Step607: The terminal removes the second signal from the mixed signal to obtain the first signal.

PUE1removes the second signal from the mixed signal according to formula 4, and obtain the first signal from the mixed signal from which the second signal is removed. Formula 4 is Ŷ=Y−H2mŨ2m, where Ũ2mindicates the signal vector of the second signal, where the signal vector of the second signal is obtained by the terminal in step606, and Ŷ indicates a signal vector of the mixed signal from which the second signal is removed.

Specifically, according to formula 4, cuts the second signal transmitted by MeNB1from the mixed signal received by PUE1to obtain Ŷ; and then according to common design of a SU-MIMO receiver, PUE1detects a signal vector of the first signal transmitted by PeNB1, that is, detects the first signal, from Ŷ.

In the embodiment of the present invention, the terminal obtains the adjustment parameter according the reference signals of the first base station and the second base station, the first base station performs, according to the adjustment parameter obtained by the terminal, channel compensation on the first channel between the first base station and the terminal to obtain the second channel, and transmits the first signal to the terminal over the second channel, and the second base station transmits the second signal using the same spectrum as the first base station. The first base station performs pre-compensation on the first channel, and pre-rotates a channel matrix of the first channel, so that the terminal can detect each data stream of the first signal and the second signal from the constellation diagram corresponding to the mixed signal of the first signal and the second signal, In this way, the first base station and the second base station can use the same spectrum to transmit signals, which improves system throughput.

Persons of ordinary skills in the art may understand that all or part of steps in the foregoing method embodiments may be implemented by a program instructing relevant hardware. The program may be stored in a computer readable storage medium. When the program is executed, the steps in the foregoing method embodiments are performed. The storage medium includes various media that can store program codes, such as a ROM, a RAM, a magnetic disk or an optical disk.

FIG. 7is a schematic diagram of a first embodiment of a base station according to the present invention. As shown inFIG. 7, the base station includes: a receiving module71, a channel compensating module73, and a transmitting module75.

The base station in this embodiment is the first base station in the embodiments of the present invention.

The receiving module71is configured to receive an adjustment parameter transmitted by a terminal, where the adjustment parameter is obtained by the terminal according to reference signals separately transmitted by a first base station and a second base station.

The channel compensating module73is configured to perform, according to the adjustment parameter received by the receiving module71, channel compensation on a first channel between the first base station and the terminal to obtain a second channel.

The transmitting module75is configured to transmit the first signal to the terminal over the second channel obtained by the channel compensating module73, so that the terminal obtains a first signal from a mixed signal of the first signal and a second signal that is transmitted by the second base station. The first signal and the second signal are transmitted by the first base station and the second base station using a same spectrum to the terminal, respectively; and the strength of the second signal is greater than that of the first signal.

For working principles and working procedures of modules in the embodiment of the present invention, reference is made to the description of the first method embodiment; the details are not repeated here.

In the embodiment of the present invention, the terminal obtains the adjustment parameter according the reference signals of the first base station and the second base station. The first base station performs, according to the adjustment parameter obtained by the terminal, channel compensation on the first channel between the first base station and the terminal to obtain the second channel, and transmits the first signal to the terminal over the second channel, so that the terminal can obtain the first signal from the mixed signal of the first signal and the second signal that is transmitted by the second base station using the same spectrum as that of the first signal. In this way, the first base station and the second base station are capable of using the same spectrum to transmit signals, improving system throughput.

FIG. 8is a schematic diagram of a second embodiment of a base station according to the present invention. Based on the embodiment shown inFIG. 7, a channel compensating module73may include: a first compensating unit731and/or a second compensating unit733.

The adjustment parameter may include A1and B1, or the adjustment parameter may include P.

The first compensating unit731is configured to, when the terminal has a single antenna, perform, according to formula 1 including A1and B1, channel compensation on a first channel to obtain a second channel, where formula 1 is H1p′=H1p×eiA1×B1, H1pindicates the first channel, H1p′indicates the second channel, A1=ang(H1m)_ang(H1p),

B1=min⁡(H1mγ⁢H1p,1),
γ is greater than 1, |H1p| indicates a modulus of the first channel, ang (H1p) indicates a phase of the first channel, H1mindicates a channel between a second base station and a terminal, |H1m| indicates a modulus of the channel between the second base station and the terminal, and ang(H1m) indicates a phase of the channel between the second base station and the terminal.

The second compensating unit733is configured to, when the terminal, the first base station and the second base station include K antennas each, perform, according to formula 2 including P, channel compensation on the first channel to obtain the second channel. Formula 2 is H2p′=H2pP, where H2pindicates a channel matrix corresponding to the first channel, H2p′indicates a channel matrix corresponding to the second channel, and P=A2·H2m. H2m=(H2a,bm)|a=1,2, . . . , K;b=1,2, . . . , K, where H2mindicates a channel matrix from the second base station to the terminal, and H2a,bmindicates a channel from a bth antenna of the second base station to an ath antenna of the terminal. H2p=(H2a,bp)|a=1,2, . . . , K;b=1,2, . . . , K, where H2a,bpindicates a first channel from a bth antenna of the first base station to the ath antenna of the terminal, and (H2p)* indicates a conjugate transpose of matrix H2p·A2=α(H2p)−1or A2α(H2p)*(H2p(H2p)*+βI)−1, where α is used to ensure that a sum of elements on a diagonal line after matrix P is multiplied by the conjugate transpose of matrix P is smaller than or equal to 1, I indicates a unit matrix, and β indicates power of noise on each antenna of the terminal. K>1.

For working principles and working procedures of modules and units in the embodiment of the present invention, reference is made to the description of the foregoing method embodiments, the details are not repeated here.

In the embodiment of the present invention, the terminal obtains the adjustment parameter according the reference signals of the first base station and the second base station. The first base station performs, according to the adjustment parameter obtained by the terminal, channel compensation on the first channel between the first base station and the terminal to obtain the second channel, and transmits the first signal to the terminal over the second channel, so that the terminal can obtain the first signal from the mixed signal of the first signal and the second signal that is transmitted by the second base station using the same spectrum as that of the first signal. In this way, the first base station and the second base station can use the same spectrum to transmit signals, which improves system throughput.

FIG. 9is a schematic diagram of a first embodiment of a terminal according to the present invention. As shown inFIG. 9, the terminal includes: an obtaining module91, a transmitting module93, a receiving module95, and a processing module97.

The obtaining module91is configured to obtain an adjustment parameter according to reference signals separately transmitted by a first base station and a second base station.

The transmitting module93is configured to transmit the adjustment parameter obtained by the obtaining module91to the first base station, so that the first base station performs, according to the adjustment parameter, channel compensation on a first channel between the first base station and a terminal to obtain a second channel.

The receiving module95is configured to receive a mixed signal of a first signal transmitted by the first base station over the second channel and a second signal transmitted by the second base station.

The processing module97is configured to obtain a first signal from the mixed signal received by the receiving module95. The first signal and the second signal are transmitted by the first base station and the second base station using a same spectrum to the terminal, respectively; and the strength of the second signal is greater than that of the first signal.

For working principles and working procedures of modules in the embodiment of the present invention, reference is made to the description of the second method embodiment; the details are not repeated here.

In the embodiment of the present invention, the terminal obtains the adjustment parameter according the reference signals of the first base station and the second base station, and transmits the adjustment parameter to the first base station, so that the first base station performs, according to the adjustment parameter obtained by the terminal, channel compensation on the first channel between the first base station and the terminal to obtain the second channel. The first base station transmits the first signal to the terminal over the second channel and the terminal obtains the first signal from the mixed signal of the first signal and the second signal that is transmitted by the second base station using the same spectrum as that of the first signal. In this way, the first base station and the second base station can use the same spectrum to transmit signals, which improves system throughput.

FIG. 10is a schematic diagram of a second embodiment of a terminal according to the present invention. Based on the embodiment shown inFIG. 9, an obtaining module91may include: a first obtaining unit911and/or a second obtaining unit913; and an processing module97includes a first processing module970, and/or the processing module97includes a second processing module971, an obtaining unit973, and a generating unit975.

An adjustment parameter may include A1and B1, or the adjustment parameter may include P.

The second obtaining module911is configured to obtain A1and B1according to reference signals separately transmitted by a first base station and a second base station. A1=ang (H1m)_ang(H1p),

B1=min⁡(H1mγ⁢H1p,1);
where H1pfirst channel, |H1p| indicates a modulus of the first channel, ang(H1p) indicates a phase of the first channel, H1mindicates a channel between the second base station and the terminal, |H1m| indicates a modulus of the channel between a second base station and a terminal, ang(H1m) indicates a phase of the channel between the second base station and the terminal, and γ is greater than 1.

The second obtaining module913is configured to obtain P according to the reference signals separately transmitted by the first base station and the second base station. P=A2·H2m, where A2=α(H2p)−1, or A2=α(H2p)*(H2p(H2p)*+βI)−1,

Where, H2m=(H2a,bm)|a=1,2, . . . , K;b=1,2, . . . , K, H2mindicating a channel matrix from the second base station to the terminal, and H2a,bmindicating a channel from a bth antenna of the second base station to an ath antenna of the terminal;

H2p=(H2a,bp)|a=1,2, . . . , K;b=1,2, . . . , K, H2pindicating a channel matrix corresponding to the first channel, H2a,bpindicating a first channel from a bth antenna of the first base station to the ath antenna of the terminal; (H2p)* indicates a conjugate transpose of matrix H2p; and α is used to ensure that a sum of elements on a diagonal line after matrix P is multiplied by the conjugate transpose of matrix P is smaller than or equal to 1, I indicates a unit matrix, and β indicates the power of noise on each antenna of the terminal.

The first processing unit970is configured to, when the adjustment parameter includes A1and B1, obtain the first signal from the mixed signal according to a minimum distance principle, the mixed signal, and a constellation diagram corresponding to the mixed signal.

The second processing unit971is configured to, when the adjustment parameter includes P, process the mixed signal into a third signal according to formula 3. Formula 3 is {tilde over (Y)}=BY, where Y indicates a signal vector of the mixed signal, {tilde over (Y)} indicates a signal vector of the third signal, and B=(H2m)−1or B=((H2m)*H2m+βI)−1(H2m)*.

The obtaining unit973is configured to obtain, according to the minimum distance principle, the third signal, and a constellation diagram corresponding to the third signal, the second signal from the third signal generated by the second processing unit971.

The generating unit975is configured to remove, from the mixed signal, the second signal obtained by the obtaining unit973, to obtain the first signal.

The generating unit975is specifically configured to remove, according to formula 4, the second signal from the mixed signal, to obtain the first signal from the mixed signal from which the second signal is removed. Formula 4 is Ŷ=Y−H2mŨ2mwhere Ũ2mindicates a signal vector of the second signal obtained by the terminal; and Ŷ indicates a signal vector of the mixed signal from which the second signal is removed.

For working principles and working procedures of modules and units in this embodiment, reference is made to the description of the foregoing method embodiments, the details are not repeated here.

In the embodiment of the present invention, the terminal obtains the adjustment parameter according the reference signals of the first base station and the second base station, and transmits the adjustment parameter to the first base station, so that the first base station performs, according to the adjustment parameter obtained by the terminal, channel compensation on the first channel between the first base station and the terminal to obtain the second channel. The first base station transmits the first signal to the terminal over the second channel and the terminal obtains the first signal from the mixed signal of the first signal and the second signal that is transmitted by the second base station using the same spectrum as that of the first signal. In this way, the first base station and the second base station can use the same spectrum to transmit signals, which improves system throughput.

An embodiment of the present invention further provides a data transmission processing system. The system includes a second base station, a base station in any one of the embodiments shown inFIG. 7andFIG. 8, and a terminal in any one of the embodiments shown inFIG. 9andFIG. 10. The second base station may be a macro base station.

For the working principles and working procedures of the base stations and terminal in the embodiment of the present invention, reference is made to the description of the foregoing method embodiments, the details are not repeated here.

In the embodiment of the present invention, the terminal obtains the adjustment parameter according the reference signals of the first base station and the second base station, and transmits the adjustment parameter to the first base station, so that the first base station performs, according to the adjustment parameter obtained by the terminal, channel compensation on the first channel between the first base station and the terminal to obtain the second channel. The first base station transmits the first signal to the terminal over the second channel and the terminal obtains the first signal from the mixed signal of the first signal and the second signal that is transmitted by the second base station using the same spectrum as that of the first signal. In this way, the first base station and the second base station can use the same spectrum to transmit signals, which improves system throughput.

Finally, it should be noted that the foregoing embodiments are merely used for illustrating the technical solutions of the present invention, but not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, persons of ordinary skill in the art should understand that: modifications can be made to the technical solutions recorded in the foregoing embodiments, or equivalent replacements can be made to some technical features in the technical solutions; and these modifications or replacements do not cause the essence of corresponding technical solutions to depart from the spirit and scope of the present invention.