CN103036643A - Method of eliminating distractions between communities, relay nodes and base stations thereof - Google Patents

Abstract

The invention provides a method of eliminating distractions between communities as well as relay nodes and base stations utilizing the method. The method of eliminating distractions between communities includes that the relay nodes receive signals sent by mobile terminals of an area which are covered by adjacent base stations at a first time slot, process the received signals based on network code and transmit the processed signals to adjacent base stations at the second time slot. According to the method, required data are obtained by joint decoding the signals transmitted by the relay nodes from the mobile terminals and signals directly received from the mobile terminals, thus the problem of distractions between communities is effectively solved, and throughput of community-edge users is improved.

Description

Inter-cell interference cancellation method, via node and base station

Technical field

The present invention relates to wireless communication technology, particularly inter-cell interference cancellation method, via node and base station.

Background technology

In current cellular system, the obtainable data rate of user depends on the residing position of user to a great extent.For example, the data rate of cellular system small area edge customer is well below the user of center of housing estate.This mainly is because due to the propagation characteristic of signal in wireless environment.Those skilled in the art will appreciate that the user received signal far away apart from the base station, behind the process space loss, its signal strength signal intensity certainly will weaken, and his obtainable data rate will reduce so naturally.If overcome space loss by the transmitted power that increases base station edge user, if also namely the base station is overcoming space loss by the transmitting power that increases the edge user, can cause so this base station that the interference of neighbor cell is increased, thereby still can cause the reduction of data rate of the edge customer of neighbor cell.Therefore, the problem that how to solve presence of intercell interference is one of data rate root problem to be solved that improves edge customer.

Summary of the invention

In order to address the above problem, presence of intercell interference can effectively be eliminated in via node and base station that embodiments of the invention provide a kind of inter-cell interference cancellation method and realized the method, improves the throughput of edge customer.

A kind of inter-cell interference cancellation method that the embodiment of the invention provides comprises: the via node signal that portable terminal sends in the first time slot receives the base station range that is adjacent; Via node carries out the processing of coding Network Based to the signal that receives; And the signal of via node after the second time slot will be processed is forwarded to the base station that is adjacent.

Wherein, via node comprises the processing that the signal that receives carries out coding Network Based: via node amplifies processing to the signal that receives; Or via node is eliminated noise and modulation treatment again to the signal that receives; Perhaps via node is eliminated noise processed and compression processing to the signal that receives; Or via node comprises the processing that the signal that receives carries out coding Network Based:

A, judge whether and to carry out the noise Processing for removing to the signal that receives according to the channel condition between via node and the base station, if so, then the signal that receives is carried out the noise Processing for removing, then execution in step B; Otherwise, the signal that receives is amplified;

B, judge whether and will the signal behind the noise Processing for removing be compressed according to the channel condition between via node and the base station, if so, then to compressing through the signal behind the noise Processing for removing; Otherwise, to again modulating through the signal behind the noise Processing for removing.

Said method further comprises: the base station signal that portable terminal sends in the first time slot receives self and the base station range that is adjacent; The signal of base station after the processing that the second time slot reception via node sends; The base station obtains the signal that portable terminal sends in self coverage according to carry out combined decoding from the signal that receives and the signal that receives in the second time slot in the first time slot.

The base station comprises according to carry out combined decoding from the signal that receives and the signal that receives in the second time slot in the first time slot: joint-detection is at first carried out to signal and the signal after the processing that the via node that the second time slot receives sends that portable terminal in self and the base station range that is adjacent that receive in the first time slot sends in the base station, obtain the log-likelihood ratio of each bit that signal comprises that portable terminal sends in self coverage, and then use decoder and decipher the signal that obtains portable terminal transmission in self coverage.At this, above-mentioned decoder is for supporting the decoder of soft information decoding, for example Turbo decoder, ldpc decoder etc.

Via node comprises the processing that the signal that receives carries out coding Network Based: described via node amplifies processing to the signal that receives; Described joint-detection comprises: described base station utilizes following formula to obtain the log-likelihood ratio of each bit that signal comprises that portable terminal sends in self coverage:

$\mathrm{LLR}\left(b_i\right)=\log \left(\frac{\underset{x_1\&Element;{\mathrm{<figure-callout\; id="0"\; label="S"\; filenames="HDA00002187709700031.png,HDA00002187709700032.png"\; state="\{\{state\}\}">S</figure-callout>}}_0,x_2\&Element;S}{\mathrm{\&Sigma;}}P(y_1\left(1\right),y_1\left(2\right)/x_1,x_2)}{\underset{x_1\&Element;{\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="HDA00002187709700032.png"\; state="\{\{state\}\}">S</figure-callout>}}_1,x_2\&Element;S}{\mathrm{\&Sigma;}}P(y_1\left(1\right),y_1\left(2\right)/x_1,x_2)}\right)$

Wherein, P (y ₁(1), y ₁(2)/x ₁, x ₂)=P (y ₁(1)/x ₁, x ₂) P (y ₁(2)/x ₁, x ₂), P (y ₁(1)/x ₁, x ₂), P (y ₁(2)/x ₁, x ₂) calculate by following formula:

$P(y_1\left(1\right)/x_1,x_2)=\frac{1}{\mathrm{\&pi;}{N}_0}\exp \{-\frac{{\left|\right|y_1\left(1\right)-h_{11}{x}_1-h_{21}{x}_2\left|\right|}^2}{\left|\right|{\mathrm{<figure-callout\; id="0"\; label="N"\; filenames="HDA00002187709700031.png,HDA00002187709700032.png"\; state="\{\{state\}\}">N</figure-callout>}}_0\left|\right|}\}$

$P(y_1\left(2\right)/x_1,x_2)=\frac{1}{\mathrm{\&pi;}{\mathrm{<figure-callout\; id="0"\; label="N"\; filenames="HDA00002187709700031.png,HDA00002187709700032.png"\; state="\{\{state\}\}">N</figure-callout>}}_0}\exp \{-\frac{{\left|\right|y_1\left(2\right)-\mathrm{\&alpha;}\&CenterDot;{\mathrm{<figure-callout\; id="1"\; label="g"\; filenames="HDA00002187709700032.png"\; state="\{\{state\}\}">g</figure-callout>}}_1\&CenterDot;g_3{x}_1-\mathrm{\&alpha;}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="g"\; filenames="HDA00002187709700032.png"\; state="\{\{state\}\}">g</figure-callout>}}_2\&CenterDot;g_4{x}_2\left|\right|}^2}{\left|\right|{\mathrm{<figure-callout\; id="0"\; label="N"\; filenames="HDA00002187709700031.png,HDA00002187709700032.png"\; state="\{\{state\}\}">N</figure-callout>}}_0\left|\right|}\}$

Wherein, y ₁(1) represents the first mixed signal that the first base station BS 1 receives at the first time slot; y ₁(2) represent the 3rd mixed signal that the first base station BS 1 receives at the second time slot; h ₁₁Represent the signal impulse response of the channel of the first mobile terminal MS 1 to first base station BS 1; h ₂₁Represent the signal impulse response of the channel of the second mobile terminal MS 2 to first base station BSs 1; x ₁And x ₂Represent respectively the signal that the first mobile terminal MS 1 and the second mobile terminal MS 2 send at the first time slot; g ₁And g ₂Represent respectively the first mobile terminal MS 1 and the second mobile terminal MS 2 to the signal impulse response of the channel of via node; g ₃And g ₄Represent respectively via node to the signal impulse response of the channel of the first base station BS 1 and the second base station BS 2; N ₀Represent the power spectral density of noise; α is the power amplification factor of via node; S ₀Refer to when given bit position is 0 corresponding QAM modulation constellation points; S ₁Refer to when particular bit position is 1 corresponding QAM modulation constellation points.S then represents all constellation point that the QAM modulation comprises.

Via node comprises the processing that the signal that receives carries out coding Network Based: described via node is eliminated noise and modulation treatment again to the signal that receives; Wherein, described noise is eliminated and is adopted following formula to realize $(S_{\min }^{\left(1\right)},S_{\min }^{\left(2\right)})=\underset{x_{}}{\mathrm{<figure-callout\; id="1"\; label="arg\; x"\; filenames="HDA00002187709700032.png"\; state="\{\{state\}\}">arg</figure-callout>}}\min (y_r-{\mathrm{<figure-callout\; id="1"\; label="g"\; filenames="HDA00002187709700032.png"\; state="\{\{state\}\}">g</figure-callout>}}_1\&CenterDot;x_1-{\mathrm{<figure-callout\; id="2"\; label="g"\; filenames="HDA00002187709700032.png"\; state="\{\{state\}\}">g</figure-callout>}}_2\&CenterDot;x_2);$ Described again modulation treatment comprises: via node is obtaining

Afterwards, according to

Determine the first mobile terminal MS 1 and the second position of mobile terminal MS 2 symbol that sends in the constellation table in the second mixed signal of receiving

And then utilize and compare S ⁽¹⁾And S ⁽²⁾More the constellation table of high order modulation is modulated the second mixed signal that receives again, and generates x _rAnd forward;

Described joint-detection comprises: described base station utilizes following formula to obtain the log-likelihood ratio of each bit that signal comprises that portable terminal sends in self coverage:

$\mathrm{LLR}\left(b_i\right)=\log \left(\frac{\underset{x_1\&Element;{\mathrm{<figure-callout\; id="0"\; label="S"\; filenames="HDA00002187709700031.png,HDA00002187709700032.png"\; state="\{\{state\}\}">S</figure-callout>}}_0,x_2\&Element;S}{\mathrm{\&Sigma;}}P(y_1\left(1\right),y_1\left(2\right)/x_1,x_2)}{\underset{x_1\&Element;{\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="HDA00002187709700032.png"\; state="\{\{state\}\}">S</figure-callout>}}_1,x_2\&Element;S}{\mathrm{\&Sigma;}}P(y_1\left(1\right),y_1\left(2\right)/x_1,x_2)}\right)$

Wherein, P (y ₁(1), y ₁(2)/x ₁, x ₂)=P (y ₁(1)/x ₁, x ₂) P (y ₁(2)/x ₁, x ₂), P (y ₁(1)/x ₁, x ₂), P (y ₁(2)/x ₁, x ₂) calculate by following formula:

$P(y_1\left(1\right)/x_1,x_2)=\frac{1}{\mathrm{\&pi;}{N}_0}\exp \{-\frac{{\left|\right|y_1\left(1\right)-h_{11}{x}_1-h_{21}{x}_2\left|\right|}^2}{\left|\right|{\mathrm{<figure-callout\; id="0"\; label="N"\; filenames="HDA00002187709700031.png,HDA00002187709700032.png"\; state="\{\{state\}\}">N</figure-callout>}}_0\left|\right|}\}$

$P(y_1\left(2\right)/x_1,x_2)=P(y_1\left(2\right)/x_r)=\frac{1}{\mathrm{\&pi;}{N}_0}\exp \{-\frac{{\left|\right|y_1\left(2\right)-g_3{x}_r\left|\right|}^2}{\left|\right|N_0\left|\right|}\}$

Wherein, y ₁(1) represents the first mixed signal that the first base station BS 1 receives at the first time slot; y ₁(2) represent the 3rd mixed signal that the first base station BS 1 receives at the second time slot; y _rRepresent the second mixed signal that via node receives at the first time slot; h ₁₁Represent the signal impulse response of the channel of the first mobile terminal MS 1 to first base station BS 1; h ₂₁Represent the signal impulse response of the channel of the second mobile terminal MS 2 to first base station BSs 1; x ₁And x ₂Represent respectively the signal that the first mobile terminal MS 1 and the second mobile terminal MS 2 send at the first time slot; x _rThe second mixed signal after representative is processed; g ₁And g ₂Represent respectively the first mobile terminal MS 1 and the second mobile terminal MS 2 to the signal impulse response of the channel of via node; g ₃Represent via node to the signal impulse response of the channel of the first base station BS 1; N ₀Represent the power spectral density of noise; S ₀Refer to when given bit position is 0 corresponding QAM modulation constellation points; S ₁Refer to when particular bit position is 1 corresponding QAM modulation constellation points.S then represents all constellation point that the QAM modulation comprises; S ⁽¹⁾And S ⁽²⁾Represent respectively the modulation constellation table that the first mobile terminal MS 1 and the second mobile terminal MS 2 adopt;

With

Represent respectively the symbol that the first mobile terminal MS 1 that via node estimates and the second mobile terminal MS 2 send.

Via node comprises the processing that the signal that receives carries out coding Network Based: the signal that receives is eliminated noise to described via node and compression is processed; Wherein, described noise is eliminated and is adopted following formula to realize $(S_{\min }^{\left(1\right)},S_{\min }^{\left(2\right)})=\underset{x_{}}{\mathrm{<figure-callout\; id="1"\; label="arg\; x"\; filenames="HDA00002187709700032.png"\; state="\{\{state\}\}">arg</figure-callout>}}\min (y_r-{\mathrm{<figure-callout\; id="1"\; label="g"\; filenames="HDA00002187709700032.png"\; state="\{\{state\}\}">g</figure-callout>}}_1\&CenterDot;x_1-{\mathrm{<figure-callout\; id="2"\; label="g"\; filenames="HDA00002187709700032.png"\; state="\{\{state\}\}">g</figure-callout>}}_2\&CenterDot;x_2);$ Described compression is processed and comprised: via node is obtaining

Afterwards, according to

Determine the first mobile terminal MS 1 and the second position of mobile terminal MS 2 symbol that sends in the constellation table in the second mixed signal of receiving

And then according to formula $x_r=S^{\left(1\right)}\left({\mathrm{index}}_{\min }^{\left(1\right)}\right)+S^{\left(2\right)}\left({\mathrm{index}}_{\min }^{\left(2\right)}\right)$ Carry out constellation mapping, generate x _rAnd forward; Described joint-detection comprises: described base station utilizes following formula to obtain the log-likelihood ratio of each bit that signal comprises that portable terminal sends in self coverage:

$\mathrm{LLR}\left(b_i\right)=\log \left(\frac{\underset{x_1\&Element;{\mathrm{<figure-callout\; id="0"\; label="S"\; filenames="HDA00002187709700031.png,HDA00002187709700032.png"\; state="\{\{state\}\}">S</figure-callout>}}_0,x_2\&Element;S}{\mathrm{\&Sigma;}}P(y_1\left(1\right),y_1\left(2\right)/x_1,x_2)}{\underset{x_1\&Element;{\mathrm{<figure-callout\; id="1"\; label="S"\; filenames="HDA00002187709700032.png"\; state="\{\{state\}\}">S</figure-callout>}}_1,x_2\&Element;S}{\mathrm{\&Sigma;}}P(y_1\left(1\right),y_1\left(2\right)/x_1,x_2)}\right)$

Wherein, P (y ₁(1), y ₁(2)/x ₁, x ₂)=P (y ₁(1)/x _i, x ₂) P (y ₁(2)/x ₁, x ₂), P (y ₁(1)/x ₁, x ₂), P (y ₁(2)/x ₁, x ₂) calculate by following formula:

$P(y_1\left(1\right)/x_1,x_2)=\frac{1}{\mathrm{\&pi;}{N}_0}\exp \{-\frac{{\left|\right|y_1\left(1\right)-h_{11}{x}_1-h_{21}{x}_2\left|\right|}^2}{\left|\right|{\mathrm{<figure-callout\; id="0"\; label="N"\; filenames="HDA00002187709700031.png,HDA00002187709700032.png"\; state="\{\{state\}\}">N</figure-callout>}}_0\left|\right|}\}$

$P(y_1\left(2\right)/x_1,x_2)=P(y_1\left(2\right)/x_r)=\frac{1}{\mathrm{\&pi;}{N}_0}\exp \{-\frac{{\left|\right|y_1\left(2\right)-g_3{x}_r\left|\right|}^2}{\left|\right|N_0\left|\right|}\}$

Wherein, y ₁(1) represents the first mixed signal that the first base station BS 1 receives at the first time slot; y ₁(2) represent the 3rd mixed signal that the first base station BS 1 receives at the second time slot; y _rRepresent the second mixed signal that via node receives at the first time slot; h ₁₁Represent the signal impulse response of the channel of the first mobile terminal MS 1 to first base station BS 1; h ₂₁Represent the signal impulse response of the channel of the second mobile terminal MS 2 to first base station BSs 1; x ₁And x ₂Represent respectively the signal that the first mobile terminal MS 1 and the second mobile terminal MS 2 send at the first time slot; x _rThe second mixed signal after representative is processed; g ₁And g ₂Represent respectively the first mobile terminal MS 1 and the second mobile terminal MS 2 to the signal impulse response of the channel of via node; g ₃Represent via node to the signal impulse response of the channel of the first base station BS 1; N ₀Represent the power spectral density of noise; S ₀Refer to when given bit position is 0 corresponding QAM modulation constellation points; S ₁Refer to when particular bit position is 1 corresponding QAM modulation constellation points.S then represents all constellation point that the QAM modulation comprises; S ⁽¹⁾And S ⁽²⁾Represent respectively the modulation constellation table that the first mobile terminal MS 1 and the second mobile terminal MS 2 adopt;

With

Represent respectively the symbol that the first mobile terminal MS 1 that via node estimates and the second mobile terminal MS 2 send.

Said method can further include: the portable terminal pair of determining the associating data retransmission.

Wherein, the portable terminal of determining the associating data retransmission is to comprising: portable terminal is measured the reference signal of this residential quarter and neighbor cell; If the difference of the reference signal strength of this residential quarter and neighbor cell is less than predefined reference signal thresholding, then this portable terminal is reported the direct transfer channel condition of link of the identify label of neighbor cell and this residential quarter to this cell base station; Base station notice portable terminal is measured the reference signal of this residential quarter of transmitting via conversion link; Portable terminal obtains the channel condition of conversion link according to the reference signal of this residential quarter of transmitting via conversion link that measures, and the channel condition of conversion link is reported this cell base station; Judge according to the direct transfer channel condition of link and the channel condition of conversion link of this residential quarter whether the quality of conversion link is better than the link that direct transfers, if so, then this portable terminal is added in alternate list; And select at random portable terminal in self alternate list and a portable terminal in the neighbor cell alternate list as the portable terminal of uniting data retransmission pair.

Determine that perhaps the portable terminal of associating data retransmission is to comprising: via node is monitored the reference signal that the neighbor cell portable terminal sends; If difference from the reference signal strength of the portable terminal of two residential quarters is arranged less than predetermined the first thresholding, and the reference signal strength of described portable terminal from two residential quarters is all greater than predetermined the second thresholding, and then via node is notified base station to described two residential quarters with the reference signal form of described portable terminal from two residential quarters; The identify label of the portable terminal of above-mentioned two residential quarters is determined respectively in the base station of described two residential quarters according to the reference signal form that receives, and the portable terminal that this identify label is corresponding adds in the alternate list of self; And select at random portable terminal in self alternate list and a portable terminal in the neighbor cell alternate list as the portable terminal of uniting data retransmission pair.

In addition, above-mentioned via node can also be realized by the base station of current free time.

The via node that the embodiment of the invention provides comprises: the mixed signal receiving element is used in the mixed signal of the first time slot reception from portable terminal; The mixed signal processing unit is used for the mixed signal that receives is carried out the processing of coding Network Based; And the mixed signal retransmission unit, the mixed signal that is used for after the second time slot will be processed is forwarded to the base station that is adjacent.

The base station that the embodiment of the invention provides comprises: the joint-detection unit, be used for obtaining the log-likelihood ratio of interior portable terminal each bit that signal transmitted comprises of self coverage to carrying out joint-detection from the direct mixed signal that receives of portable terminal and at the second time slot from the mixed signal that via node receives at the first time slot; Decoder is deciphered according to the log-likelihood ratio of portable terminal each bit that signal transmitted comprises in self coverage, obtains portable terminal signal transmitted in self coverage.Above-mentioned decoder is for supporting the decoder of soft information decoding, such as Turbo decoder, ldpc decoder etc.

As previously mentioned, embodiments of the invention are by introducing via node RS between adjacent base station, and after via node is processed the signal from portable terminal that self receives, be forwarded to again the base station that is adjacent, so that the base station can be carried out combined decoding from the signal of portable terminal and the signal that self directly receives from portable terminal and obtain self required data by what utilize that via node transmits, thereby effectively solve the problem of presence of intercell interference, improve the throughput of Cell Edge User.

Description of drawings

Fig. 1 is inter-cell interference cancellation method flow diagram of the present invention;

Fig. 2 is the structural representation of the wireless communication system of inter-cell interference cancellation method application of the present invention;

Fig. 3 is the flow chart of the adaptively selected processing mode of the described via node of the embodiment of the invention;

Fig. 4 is the internal structure schematic diagram of the described via node of the embodiment of the invention;

Fig. 5 is the internal structure schematic diagram of the described base station of the embodiment of the invention;

Fig. 6 (a) and (b) shown respectively when distance between via node and the portable terminal does not have via node when being 10 meters and 50 meters and the relation between signal to noise ratio (snr) and the Block Error Rate (BLER) when adopting the embodiment of the invention 1 to 3 described method;

Fig. 7 has shown that the described How to choose of the embodiment of the invention unites the right method flow of portable terminal of data retransmission;

Fig. 8 has shown that the described How to choose of another embodiment of the present invention unites the right method flow of portable terminal of data retransmission; And

Fig. 9 is a kind of network topology schematic diagram.

Embodiment

In order to make purpose of the present invention, technical scheme and advantage clearer, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, is not intended to limit the present invention.

The invention provides a kind of inter-cell interference cancellation method, the method arranges via node (RS, relay station) between adjacent base station, as shown in Figure 1, comprise the steps:

Step 101: the via node signal that portable terminal sends in the first time slot receives the base station range that is adjacent;

Step 102: via node carries out the processing of coding Network Based to the signal that receives;

Step 103: the signal of via node after the second time slot will be processed is forwarded to the base station that is adjacent.

In the inter-cell interference cancellation method that the invention described above provides, the base station signal that portable terminal sends in the first time slot receives self and the base station range that is adjacent, signal after the second time slot receives the processing that via node sends, and obtain the signal that portable terminal sends in self coverage according to carry out combined decoding from the signal that in the first time slot, receives and the signal that in the second time slot, receives.

Describe said method in detail below in conjunction with Fig. 2.Fig. 2 is the wireless communication system architecture schematic diagram that the method for the invention is used.

As shown in Figure 2, in order to solve the first adjacent base station BS 1 and the interference between the second base station BS 2, between the first adjacent base station BS 1 and the second base station BS 2, introduced via node RS.This via node has been arranged, the first mobile terminal MS 1 in the first base station BS 1 coverage and the second mobile terminal MS 2 in the second base station BS 2 coverages just can send data simultaneously, the data that send are sent to the first base station BS 1, the second base station BS 2 and via node RS at the first time slot.At this moment, what the first base station BS 1 and the second base station BS 2 were received is a mixed signal, is called the first mixed signal.The first mixed signal can calculate by following formula (1) and (2):

y ₁(1)=h ₁₁x ₁+h ₂₁x ₂+z ₁ （1）

y ₂(1)=h ₁₂x ₁+h ₂₂x ₂+z ₂ （2）

Wherein, y ₁(1) and y ₂(1) represents respectively the first mixed signal that the first base station BS 1 and the second base station BS 2 receive at the first time slot; h ₁₁Represent the signal impulse response of the channel of the first mobile terminal MS 1 to first base station BS 1; h ₁₂Represent the signal impulse response of the channel of the first mobile terminal MS 1 to second base station BS 2; h ₂₁Represent the signal impulse response of the channel of the second mobile terminal MS 2 to first base station BSs 1; h ₂₂Represent the signal impulse response of the channel of the second mobile terminal MS 2 to second base station BSs 2; x ₁And x ₂Represent respectively the signal that the first mobile terminal MS 1 and the second mobile terminal MS 2 send at the first time slot; z ₁And z ₂Represent respectively the noise of the first base station BS 1 and the second base station BS 2 receivers.

Can find out from above-mentioned formula, because the existence of presence of intercell interference, the first base station BS 1 and the second base station BS 2 the first time slot receive be a mixed signal and correctly demodulation obtain self required data (the first base station BS 1 obtain the data of the first mobile terminal MS 1 transmission; The second base station BS 2 obtains the data that the second mobile terminal MS 2 sends).

Because the space broadcast characteristic of signal, via node RS also can receive a mixed signal at the first time slot, is called the second mixed signal.The second mixed signal can calculate by following formula (3):

y _r=g ₁x ₁+g ₂x ₂+z _r （3）

Wherein, y _rRepresent the second mixed signal that via node receives at the first time slot; g ₁And g ₂Represent respectively the first mobile terminal MS 1 and the second mobile terminal MS 2 to the signal impulse response of the channel of via node; x ₁And x ₂Represent respectively the signal that the first mobile terminal MS 1 and the second mobile terminal MS 2 send at the first time slot; z _rRepresent the noise of via node receiver.

After via node RS processed the second mixed signal that receives, the second mixed signal after the second time slot will be processed was broadcast to the first base station BS 1 and the second base station BS 2.Like this, the first base station BS 1 and the second base station BS 2 can receive another mixed signal at the second time slot, are called the 3rd mixed signal.The 3rd mixed signal can calculate by following formula (4) and (5):

y ₁(2)=g ₃x _r+z ₁ （4）

y ₂(2)=g ₄x _r+z ₂ （5）

Wherein, y ₁(2) and y ₂(2) represent respectively the 3rd mixed signal that the first base station BS 1 and the second base station BS 2 receive at the second time slot; g ₃And g ₄Represent respectively via node to the signal impulse response of the channel of the first base station BS 1 and the second base station BS 2; x _rThe second mixed signal after representative is processed.

At last, the first base station BS 1 and the second base station BS 2 will be according to from the first mixed signals that receives in the first time slot and carry out respectively combined decoding in the 3rd mixed signal from via node that the second time slot receives and obtain self required data, also namely the first base station BS 1 according to above-mentioned y ₁(1) and y ₁(2) carry out combined decoding and obtain x ₁The second base station BS 2 is according to above-mentioned y ₂(1) and y ₂(2) carry out combined decoding and obtain x ₂

Particularly, above-mentioned joint decoding comprises: the base station is at first to carrying out joint-detection from receiving in the first time slot from the first mixed signal of portable terminal with in the 3rd mixed signal from via node that the second time slot receives, obtain the log-likelihood ratio (LLR) of each bit that signal comprises that portable terminal sends in self coverage, and then use decoder and decipher the signal that obtains the interior portable terminal transmission of self coverage, the decoder here is for supporting the decoder of soft information decoding, for example Turbo decoder, ldpc decoder etc.

The below will all adopt qam mode to describe the base station in detail as example take the first base station BS 1 and the first mobile terminal MS 1 and the second mobile terminal MS 2 to carry out the method that joint-detection obtains the log-likelihood ratio (LLR) of each bit that signal is comprised that portable terminal sends in self coverage according to the first mixed signal and the 3rd mixed signal.

As previously mentioned, the signal that obtains of the first base station BS 1 comprises: y ₁(1)=h ₁₁x ₁+ h ₂₁x ₂+ z ₁And y ₁(2)=g ₃x _r+ z ₁If what the first mobile terminal MS 1 adopted is qam mode, the first base station BS 1 just needs at first by joint-detection picked up signal X ₁The qam symbol of representative comprises the LLR information of two bit b1 and b2.

In this example, the first base station BS 1 can be determined signal X by following computing formula (6) ₁Comprise the LLR information of two bit b1 and b2: $\begin{array}{c}\mathrm{LLR}\left(b_i\right)=\log \left(\frac{P(b_i=0/y_1\left(1\right),y_1\left(2\right))}{P(b_i=1/y_1\left(1\right),y_1\left(2\right))}\right)=\log \left(\frac{\underset{x_1\&Element;S_0}{\mathrm{\&Sigma;}}P(x_1/y_1\left(1\right),y_1\left(2\right))}{\underset{x_1\&Element;S_1}{\mathrm{\&Sigma;}}P(x_1/y_1\left(1\right),y_1\left(2\right))}\right)\\ =\log \left(\frac{\underset{x_1\&Element;S_0,x_2\&Element;S}{\mathrm{\&Sigma;}}P(x_1,x_2/y_1\left(1\right),y_1\left(2\right))}{\underset{x_1\&Element;S_1,x_2\&Element;S}{\mathrm{\&Sigma;}}P(x_1,x_2/y_1\left(1\right),y_1\left(2\right))}\right)=\log \left(\frac{\underset{x_1\&Element;S_0,x_2\&Element;S}{\mathrm{\&Sigma;}}P(y_1,\left(1\right),y_1\left(2\right)/x_1,x_2)}{\underset{x_1\&Element;S1,x_2\&Element;S}{\mathrm{\&Sigma;}}P(y_1\left(1\right),y_1\left(2\right)/x_1,x_2)}\right)\end{array}---\left(6\right)$

Wherein, S ₀Refer to when given bit position is 0 corresponding QAM modulation constellation points; S ₁Refer to when particular bit position is 1 corresponding QAM modulation constellation points.S then represents all constellation point that the QAM modulation comprises.

Further, to the P (y in the above-mentioned formula (6) ₁(1), y ₁(2)/x ₁, x ₂) deriving to obtain following formula (7):

P(y ₁(1)，y ₁(2)／x ₁，x ₂)=P(y ₁(1)／x ₁，x ₂)·P(y ₁(2)／x ₁，x ₂，y ₁(1))=P(y ₁(1)／x ₁，x ₂)·P(y ₁(2)／x ₁，x ₂) （7）

Wherein, P (y ₁(1)/x ₁, x ₂) can calculate by following formula (8), wherein, N ₀Represent the power spectral density of noise:

$P(y_1\left(1\right)/{\mathrm{<figure-callout\; id="1"\; label="x"\; filenames="HDA00002187709700032.png"\; state="\{\{state\}\}">x</figure-callout>}}_1,x_2)=\frac{1}{{\mathrm{\&pi;<figure-callout\; id="0"\; label="N"\; filenames="HDA00002187709700031.png,HDA00002187709700032.png"\; state="\{\{state\}\}">N</figure-callout>}}_0}\exp \{-\frac{{\left|\right|y_1\left(1\right)-h_{11}{x}_1-h_{21}{x}_2\left|\right|}^2}{\left|\right|{\mathrm{<figure-callout\; id="0"\; label="N"\; filenames="HDA00002187709700031.png,HDA00002187709700032.png"\; state="\{\{state\}\}">N</figure-callout>}}_0\left|\right|}\}---\left(8\right)$

And P (y ₁(2)/x ₁, x ₂) the Square rule relevant to the processing mode of receive the second mixed signal with via node, will be described in more detail below.

Can be found out by said method, by between adjacent base station, introducing via node, the base station that is adjacent be processed and then be forwarded to via node will to the signal that receives after receiving from the signal of portable terminal, so that the base station can be carried out combined decoding from the signal of portable terminal and the signal that directly receives from portable terminal and obtain self required data by what via node was transmitted, thereby effectively solve the problem of presence of intercell interference, improve the throughput of Cell Edge User.

Describe below in conjunction with specific embodiments that via node RS in the said method processes the second mixed signal that receives in detail and the first base station BS 1 carries out the method for combined decoding according to the first mixed signal and the 3rd mixed signal.

Embodiment 1

In the present embodiment, via node amplifies processing to the second mixed signal that receives, and then transmits.Also in the present embodiment namely, via node is by following formula X _r=α Y _rThe second mixed signal that receives is processed, the α here is the power amplification factor of via node, arranging of α can only be considered to satisfy via node to the restriction of power, also can consider simultaneously the power of portable terminal, to realize the optimal power allocation between portable terminal and via node.

In this case, 1 obtainable signal of the first base station BS comprises: y ₁(1)=h ₁₁x ₁+ h ₂₁x ₂+ z ₁And y ₁(2)=g ₃x _r+ z ₁, wherein, x _r=α y _r=α g ₁x ₁+ α g ₂x ₂+ α z _r

If what the first mobile terminal MS 1 and the second mobile terminal MS 2 adopted is qam mode, then can determine the P (y in the above-mentioned formula (7) ₁(2)/x ₁, x ₂) can calculate by following formula (9):

$P(y_1\left(2\right)/{\mathrm{<figure-callout\; id="1"\; label="x"\; filenames="HDA00002187709700032.png"\; state="\{\{state\}\}">x</figure-callout>}}_1,x_2)=\frac{1}{\mathrm{\&pi;}{\mathrm{<figure-callout\; id="0"\; label="N"\; filenames="HDA00002187709700031.png,HDA00002187709700032.png"\; state="\{\{state\}\}">N</figure-callout>}}_0}\exp \{-\frac{{\left|\right|y_1\left(2\right)-\mathrm{\&alpha;}\&CenterDot;{\mathrm{<figure-callout\; id="1"\; label="g"\; filenames="HDA00002187709700032.png"\; state="\{\{state\}\}">g</figure-callout>}}_1\&CenterDot;g_3{x}_1-\mathrm{\&alpha;}\&CenterDot;{\mathrm{<figure-callout\; id="2"\; label="g"\; filenames="HDA00002187709700032.png"\; state="\{\{state\}\}">g</figure-callout>}}_2\&CenterDot;g_4{x}_2\left|\right|}^2}{\left|\right|{\mathrm{<figure-callout\; id="0"\; label="N"\; filenames="HDA00002187709700031.png,HDA00002187709700032.png"\; state="\{\{state\}\}">N</figure-callout>}}_0\left|\right|}\}---\left(9\right)$

In the present embodiment, calculate LLR (b by above-mentioned formula (8) and (9) when the first base station BS 1 ₁) and LLR (b ₂) after, just can be with the LLR (b that calculates ₁) and LLR (b ₂) send to decoder, can obtain original data message X through decoding ₁

Embodiment 2

In the present embodiment, via node at first carries out the noise Processing for removing to the second mixed signal that receives, and transmits after then re-modulated again.

The described noise Processing for removing of present embodiment can be realized by following formula (10):

$(S_{\min }^{\left(1\right)},S_{\min }^{\left(2\right)})=\underset{x_1\&Element;S^{\left(1\right)},x_2\&Element;S^{\left(2\right)}}{\arg }\min (y_r-{\mathrm{<figure-callout\; id="1"\; label="g"\; filenames="HDA00002187709700032.png"\; state="\{\{state\}\}">g</figure-callout>}}_1\&CenterDot;x_1-{\mathrm{<figure-callout\; id="2"\; label="g"\; filenames="HDA00002187709700032.png"\; state="\{\{state\}\}">g</figure-callout>}}_2\&CenterDot;x_2)---\left(10\right)$

Wherein, S ⁽¹⁾And S ⁽²⁾Represent respectively the modulation constellation table that the first mobile terminal MS 1 and the second mobile terminal MS 2 adopt;

With

Represent respectively the symbol that the first mobile terminal MS 1 that via node estimates and the second mobile terminal MS 2 send.

Particularly, if the first mobile terminal MS 1 and the second mobile terminal MS 2 all adopt qam mode, then satisfy $S^{\left(1\right)}=S^{\left(2\right)}=\frac{1}{\sqrt{2}}[1+j;1-j;-1+j;-1-j].$

Via node is obtaining

Afterwards, can basis

Determine the first mobile terminal MS 1 and the second position of mobile terminal MS 2 symbol that sends in the constellation table in the second mixed signal of receiving

And then utilize and compare S ⁽¹⁾And S ⁽²⁾The constellation table of high order modulation more, for example 16QAM modulates the second mixed signal that receives again, and generates x _rAnd forward.

At this moment, x _rCan generate according to following formula (11).

$x_r=S^{\left(h\right)}\left({\mathrm{index}}_{\min }^{\left(1\right)}\right)+i\&times;S^{\left(h\right)}\left({\mathrm{index}}_{\min }^{\left(2\right)}\right)---\left(11\right)$

Wherein, $S^{\left(h\right)}=\frac{1}{\sqrt{10}}[-3;-1;3;1].$

In this case, can determine P (y in the above-mentioned formula (7) ₁(1)/x ₁, x ₂) can calculate P (y by above-mentioned formula (8) ₁(2)/x ₁, x ₂) can calculate by following formula (12):

$P(y_1\left(2\right)/{\mathrm{<figure-callout\; id="1"\; label="x"\; filenames="HDA00002187709700032.png"\; state="\{\{state\}\}">x</figure-callout>}}_1,x_2)=P(y_1\left(2\right)/x_r)=\frac{1}{\mathrm{\&pi;}{\mathrm{<figure-callout\; id="0"\; label="N"\; filenames="HDA00002187709700031.png,HDA00002187709700032.png"\; state="\{\{state\}\}">N</figure-callout>}}_0}\exp \{-\frac{{\left|\right|y_1\left(2\right)-g_3{x}_r\left|\right|}^2}{\left|\right|{\mathrm{<figure-callout\; id="0"\; label="N"\; filenames="HDA00002187709700031.png,HDA00002187709700032.png"\; state="\{\{state\}\}">N</figure-callout>}}_0\left|\right|}\}---\left(12\right)$

In the present embodiment, calculate LLR (b by above-mentioned formula (8) and (12) when the first base station BS 1 ₁) and LLR (b ₂) after, just can be with the LLR (b that calculates ₁) and LLR (b ₂) send to decoder, can obtain original data message.

Embodiment 3

In the present embodiment, via node at first carries out the noise Processing for removing to the second mixed signal that receives, and then the second mixed signal after processing is compressed, and forwards at last again.

It will be appreciated by those skilled in the art that, when portable terminal is enough good to the channel condition of the direct link of base station, the base station still can obtain some information from the first mixed signal that receives in the first time slot, therefore, send again if adopt this moment the method among the upper embodiment to be modulated into 16QAM by the second mixed signal that two QAM signals form, still can waste a lot of resources.Consider above-mentioned factor, can do further compression to signal after eliminating noise in the present embodiment, specifically can be according to the first mobile terminal MS 1 and the position of the second mobile terminal MS 2 signal transmitteds in the constellation table in the signal behind the elimination noise

Do further constellation mapping and obtain signal x to be sent _r, reduce the consumption that sends resource.

In the present embodiment, above-mentioned constellation mapping can be finished by following formula (13):

$x_r=S^{\left(1\right)}\left({\mathrm{index}}_{\min }^{\left(1\right)}\right)+S^{\left(2\right)}\left({\mathrm{index}}_{\min }^{\left(2\right)}\right)---\left(13\right)$

In this case, can determine P (y in the above-mentioned formula (7) ₁(1)/x ₁, x ₂) can calculate P (y by above-mentioned formula (8) ₁(2)/x ₁, x ₂) can calculate by above-mentioned formula (12).

In the present embodiment, calculate LLR (b by above-mentioned formula (8) and (12) when the first base station BS 1 ₁) and LLR (b ₂) after, just can be with the LLR (b that calculates ₁) and LLR (b ₂) send to decoder, can obtain original data message.

Embodiment 4

In an embodiment, via node can be processed the second mixed signal that receives according to mode described in the adaptive selection above-described embodiment 1 to embodiment 3 of the channel condition between via node and the base station.

In the present embodiment, the operating process of the adaptive selection processing mode of via node mainly comprises as shown in Figure 3:

Step 301: judge whether and will carry out the noise Processing for removing to the second mixed signal that receives according to the channel condition between via node and the base station, if so, execution in step 303; Otherwise execution in step 302;

Particularly, can judge whether according to the transmitting power of the distance between UE and the via node and UE and will carry out the noise Processing for removing to the second mixed signal that receives;

Step 302: the second mixed signal that receives is amplified, then be forwarded to the base station adjacent with self;

The method of in this step, receive the second mixed signal being amplified can be with reference to the method for record in above-described embodiment 1;

Step 303: the second mixed signal that receives is carried out the noise Processing for removing, and then execution in step 304;

In this step, to the second mixed signal carry out the noise Processing for removing method can with reference in above-described embodiment 2 record method;

Step 304: judge whether and to compress the second mixed signal behind the noise Processing for removing that if so, then execution in step 305 according to the channel condition between via node and the base station; Otherwise, execution in step 306;

Particularly, can judge whether according to the transmitting power of the distance between UE and the via node and UE and will compress the second mixed signal that receives;

Step 305: to compressing through the second mixed signal behind the noise Processing for removing, the signal after then will compressing is forwarded to the base station adjacent with self;

In this step, can be with reference to the method for record in above-described embodiment 3 to the method for compressing through the second mixed signal behind the noise Processing for removing.

Step 306 is forwarded to the base station adjacent with self after again modulating through the second mixed signal behind the noise Processing for removing.

In this step, can be with reference to the method for record in above-described embodiment 2 to carrying out heavy fresh method through the second mixed signal behind the noise Processing for removing.

In the situation of the adaptively selected processing mode of this via node, P (y in the above-mentioned formula (7) also can adaptively be determined in the base station ₁(1)/x ₁, x ₂) and P (y ₁(2)/x ₁, x ₂) computational methods.

In the present embodiment, calculate LLR (b by above-mentioned formula (8) and (12) when the first base station BS 1 ₁) and LLR (b ₂) after, just can be with the LLR (b that calculates ₁) and LLR (b ₂) send to decoder, can obtain original data message.

The method of corresponding above-mentioned elimination presence of intercell interference, embodiments of the invention give via node and the base station of realizing said method.

Fig. 4 has shown the internal structure of the described via node of the embodiment of the invention.As shown in Figure 4, the described via node of the embodiment of the invention comprises:

The mixed signal receiving element is used at the signal of the first time slot reception from portable terminal;

The mixed signal processing unit is used for the signal that receives is carried out the processing of coding Network Based;

The mixed signal retransmission unit, the signal that is used for after the second time slot will be processed is forwarded to the base station that is adjacent.

Wherein, above-mentioned mixed signal processing unit can adopt such as one of front embodiment 1 to 4 described method the signal that receives is processed.Also be that above-mentioned mixed signal processing unit can comprise amplification module, be used for adopt such as method as described in the front embodiment 1 signal that receives is amplified processing.Perhaps above-mentioned mixed signal processing unit can comprise noise cancellation module and modulation module, is used for adopting respectively as front embodiment 2 described methods are carried out noise Processing for removing and modulation treatment again to the signal that receives.Or above-mentioned mixed signal processing unit can comprise noise cancellation module and compression module, is used for adopting respectively as the signal that receives is carried out the noise Processing for removing to front embodiment 3 described methods and compression is processed.

Fig. 5 has shown the internal structure of the described base station of the embodiment of the invention.As shown in Figure 5, the described base station of the embodiment of the invention comprises:

The joint-detection unit, be used for obtaining the log-likelihood ratio of interior portable terminal each bit that signal transmitted comprises of self coverage to carrying out joint-detection from the direct mixed signal that receives of portable terminal and at the second time slot from the mixed signal that via node receives at the first time slot;

Decoder is deciphered according to the log-likelihood ratio of portable terminal each bit that signal transmitted comprises in self coverage, obtains portable terminal signal transmitted in self coverage.

Wherein, above-mentioned joint-detection unit can adopt such as front embodiment 1 to 4 described method and carry out joint-detection to the mixed signal that directly receives from portable terminal at the first time slot and at the second time slot from the mixed signal that via node receives.

The below will not have the wireless communication system of via node and the Block Error Rate of several method in equivalent signal-to-noise ratio (SNR) situation that the embodiment of the invention proposes to describe the performance that the embodiment of the invention proposes to eliminate the presence of intercell interference method in detail by emulation is existing.The simulation parameter that this emulation is adopted is as shown in table 1 below:

Radius of society	500 meters
		Transmitted power	-13dBmw--4dBmw
The noise variable	-174dB／Hz
		Multipath fading	SCM-C
Path number
		6
Every footpath time delay			[0310710109017302510]*1e-9
	Path loss (user-base station)	Path Loss＝131.1+42．8*log10(d)
Path loss (user-relaying)			Path Loss＝145．4+37.5*log10(d)
	Path loss (relaying-base station)	Path Loss＝125.2+36.3*log10(d)
Chnnel coding			Turbo，1／3
	The FFT carrier number	1024
The RB number			512
	Modulator approach	QPSK
Rate-matched			3300
	Block length	1096 symbols

Table 1

Fig. 6 (a) and Fig. 6 (b) have shown respectively when the distance between via node and the portable terminal does not have via node when being 10 meters and 50 meters and the relation between signal to noise ratio (snr) and the Block Error Rate (BLER) when adopting the embodiment of the invention 1 to 3 described method.Fig. 6 (a) and Fig. 6 (b) corresponding with foursquare curve be the relation between SNR and the BLER when not having via node; The circular curve of band is corresponding is the relation between SNR and the BLER when adopting the embodiment of the invention 1 described method; With criss-cross curve corresponding be the relation between SNR and the BLER when adopting the embodiment of the invention 2 described method; With leg-of-mutton curve corresponding be the relation between SNR and the BLER when adopting the embodiment of the invention 3 described method.Can find out that from Fig. 6 (a) and Fig. 6 (b) under different signal to noise ratio conditions, the inter-cell interference cancellation method of coming proposed by the invention all is better than not having the traditional scheme of via node.

In order to make such scheme more perfect, embodiments of the invention give the right method of portable terminal that How to choose is united data retransmission, it is the method for aforementioned the first portable terminal of How to choose and the second portable terminal, the method can be cooperated by base station and portable terminal to be carried out, its idiographic flow mainly comprises the steps: as shown in Figure 7

Step 701: portable terminal is measured the reference signal of this residential quarter and neighbor cell;

Step 702: if the difference of the reference signal strength of this residential quarter and neighbor cell less than predefined reference signal thresholding, then this portable terminal is reported the direct transfer channel condition of link of the identify label (ID) of neighbor cell and this residential quarter to this cell base station;

Step 703: base station notice portable terminal is measured the reference signal of this residential quarter of transmitting via conversion link;

Step 704: portable terminal obtains the channel condition of conversion link according to the reference signal of this residential quarter of transmitting via conversion link that measures, and the channel condition of conversion link is reported this cell base station;

Step 705: judge according to the direct transfer channel condition of link and the channel condition of conversion link of this residential quarter whether the quality of conversion link is better than the link that direct transfers, if so, then this portable terminal is added in alternate list;

Step 706: select at random portable terminal in self alternate list and a portable terminal in the neighbor cell alternate list as the portable terminal of uniting data retransmission pair.

Particularly, above-mentioned this residential quarter direct transfers intensity that the channel condition of the channel condition of link and conversion link can be by the pilot signal that receives via the link that direct transfers and the intensity of the pilot signal that receives via conversion link characterizes, for example, if the intensity of the pilot signal that receives via conversion link then can add this portable terminal in alternate list greater than the intensity of the pilot signal that receives via the link that direct transfers.

Embodiments of the invention give the another kind of right method of portable terminal of selecting the associating data retransmission, and the method can be cooperated by base station and via node to be carried out, and its idiographic flow mainly comprises the steps: as shown in Figure 8

Step 801: via node is monitored the reference signal that the neighbor cell portable terminal sends;

Step 802: if difference from the reference signal strength of the portable terminal of two residential quarters is arranged less than predetermined the first thresholding, and the reference signal strength of above-mentioned portable terminal from two residential quarters is all greater than predetermined the second thresholding, and then via node is notified base station to above-mentioned two residential quarters with the reference signal form of above-mentioned portable terminal from two residential quarters;

Need to prove that above-mentioned the first thresholding and the second thresholding can rule of thumb be worth and preset;

Step 803: the ID of the portable terminal of above-mentioned two residential quarters is determined respectively in the base station of above-mentioned two residential quarters according to the reference signal form that receives, and the portable terminal that this ID is corresponding adds in the alternate list of self;

Step 804: select at random portable terminal in self alternate list and a portable terminal in the neighbor cell alternate list as the portable terminal of uniting data retransmission pair.

By above-mentioned Fig. 7 and method shown in Figure 8, can determine the portable terminal pair of associating data retransmission.At the portable terminal of having determined to unite data retransmission pair, namely determined after the first portable terminal and the second portable terminal, the method that via node in the system can be used in above-described embodiment is carried out the processing of coding Network Based to the signal from the first portable terminal and the second portable terminal that receives, and is forwarded to the base station that is adjacent again.Subsequently, the base station is carried out combined decoding by signal that via node is transmitted and the signal that directly receives from above-mentioned the first portable terminal and the second portable terminal respectively again and is obtained self required data.

Can find out that from foregoing description above-described embodiment all is to realize disturbing elimination by via node is set between adjacent base station.In the application of reality, even via node is not set in network, also can utilize the adjacent base station of temporary transient free time, it is come processing to receiving, carry out coding Network Based from the signal of portable terminal as above-mentioned via node, and then be transmitted to adjacent base station, thereby realize interference elimination method of the present invention.Fig. 9 is a kind of network topology schematic diagram.In network shown in Figure 9, BS1 and BS2 are two adjacent base stations, and wherein, BS1 is the serving BS of mobile terminal MS 1; BS2 is the serving BS of mobile terminal MS 2.BS3 is and the equal adjacent base station of BS1 and BS2, and BS3 does not need the portable terminal of serving or temporarily relatively more idle.In this case, can BS3 be set to the function of a via node, also namely in the first step, the signal that BS3 mobile terminal MS 1 and MS2 in the first time slot receives the base station BS 1 that is adjacent and BS2 coverage send; At second step, BS3 carries out the processing of coding Network Based to the signal that receives; At last, in the 3rd step, the signal of BS3 after the second time slot will be processed is forwarded to base station BS 1 and the BS2 that is adjacent.Like this, base station BS 1 and BS2 can be respectively carry out combined decoding from the signal of mobile terminal MS 1 and MS2 and the signal that directly receives from mobile terminal MS 1 and MS2 and obtain self required data by what BS3 was transmitted, thereby effectively solve the problem of presence of intercell interference, improve the throughput of cell edge terminal.

Under this application scenarios, also can adopt identical with Fig. 7 or select the portable terminal of associating data retransmission to MS1 and MS2 with the similar method of Fig. 8.Need to prove, when adopting with the similar method of Fig. 8, the alternative via node in the base station of current free time is realized that the function of via node in the method shown in Figure 8 gets final product.

By such scheme, can not utilize temporary transient relatively more idle base station to realize the function of via node even via node is set in the network yet, thereby effectively solve the problem of presence of intercell interference, improve the throughput of cell edge terminal.

The above only is preferred embodiment of the present invention, and is in order to limit the present invention, within the spirit and principles in the present invention not all, any modification of making, is equal to replacement, improvement etc., all should be included within the scope of protection of the invention.

Claims (16)

1. an inter-cell interference cancellation method is characterized in that, comprising:

The via node signal that portable terminal sends in the first time slot receives the base station range that is adjacent;

Via node carries out the processing of coding Network Based to the signal that receives; And

The signal of via node after the second time slot will be processed is forwarded to the base station that is adjacent.

2. method according to claim 1, wherein, described via node comprises the processing that the signal that receives carries out coding Network Based: described via node amplifies processing to the signal that receives.

3. method according to claim 1, wherein, described via node comprises the processing that the signal that receives carries out coding Network Based: described via node is eliminated noise and modulation treatment again to the signal that receives.

4. method according to claim 1, wherein, described via node comprises the processing that the signal that receives carries out coding Network Based: the signal that receives is eliminated noise processed to described via node and compression is processed.

5. method according to claim 1, wherein, described via node comprises the processing that the signal that receives carries out coding Network Based:

A, judge whether and to carry out the noise Processing for removing to the signal that receives according to the channel condition between via node and the base station, if so, then the signal that receives is carried out the noise Processing for removing, then execution in step B; Otherwise, the signal that receives is amplified;

B, judge whether and will the signal behind the noise Processing for removing be compressed according to the channel condition between via node and the base station, if so, then to compressing through the signal behind the noise Processing for removing; Otherwise, to again modulating through the signal behind the noise Processing for removing.

6. method according to claim 1 further comprises:

The base station signal that portable terminal sends in the first time slot receives self and the base station range that is adjacent;

The signal of base station after the processing that the second time slot reception via node sends;

The base station obtains the signal that portable terminal sends in self coverage according to carry out combined decoding from the signal that receives and the signal that receives in the second time slot in the first time slot.

7. method according to claim 6, wherein, described base station comprises according to carry out combined decoding from the signal that receives and the signal that receives in the second time slot in the first time slot: joint-detection is at first carried out to signal and the signal after the processing that the via node that the second time slot receives sends that portable terminal in self and the base station range that is adjacent that receive in the first time slot sends in the base station, obtain the log-likelihood ratio of each bit that signal comprises that portable terminal sends in self coverage, and then use decoder and decipher the signal that obtains portable terminal transmission in self coverage.

8. method according to claim 7, wherein, described via node comprises the processing that the signal that receives carries out coding Network Based: described via node amplifies processing to the signal that receives;

Described joint-detection comprises: described base station utilizes following formula to obtain the log-likelihood ratio of each bit that signal comprises that portable terminal sends in self coverage:

$\mathrm{LLR}\left(b_i\right)=\log \left(\frac{\underset{x_1\&Element;S_0,x_2\&Element;S}{\mathrm{\&Sigma;}}P(y_1\left(1\right),y_1\left(2\right)/x_1,x_2)}{\underset{x_1\&Element;S_1,x_2\&Element;S}{\mathrm{\&Sigma;}}P(y_1\left(1\right),y_1\left(2\right)/x_1,x_2)}\right)$

Wherein, P (y ₁(1), y ₁(2)/x ₁, x ₂)=P (y ₁(1)/x ₁, x ₂) P (y ₁(2)/x ₁, x ₂), P (y ₁(1)/x ₁, x ₂), P (y ₁(2)/x ₁, x ₂) calculate by following formula:

$P(y_1\left(1\right)/x_1,x_2)=\frac{1}{{\mathrm{\&pi;N}}_0}\exp \{-\frac{{\left|\right|y_1\left(1\right)-h_{11}{x}_1-h_{21}{x}_2\left|\right|}^2}{\left|\right|N_0\left|\right|}\}$

$P(y_1\left(2\right)/x_1,x_2)=\frac{1}{\mathrm{\&pi;}{N}_0}\exp \{-\frac{{\left|\right|y_1\left(2\right)-\mathrm{\&alpha;}\&CenterDot;g_1\&CenterDot;g_3{x}_1-\mathrm{\&alpha;}\&CenterDot;g_2\&CenterDot;g_4{x}_2\left|\right|}^2}{\left|\right|N_0\left|\right|}\}$

Wherein, y ₁(1) represents the first mixed signal that the first base station BS 1 receives at the first time slot; y ₁(2) represent the 3rd mixed signal that the first base station BS 1 receives at the second time slot; h ₁₁Represent the signal impulse response of the channel of the first mobile terminal MS 1 to first base station BS 1; h ₂₁Represent the signal impulse response of the channel of the second mobile terminal MS 2 to first base station BSs 1; x ₁And x ₂Represent respectively the signal that the first mobile terminal MS 1 and the second mobile terminal MS 2 send at the first time slot; g ₁And g ₂Represent respectively the first mobile terminal MS 1 and the second mobile terminal MS 2 to the signal impulse response of the channel of via node; g ₃And g ₄Represent respectively via node to the signal impulse response of the channel of the first base station BS 1 and the second base station BS 2; N ₀Represent the power spectral density of noise; α is the power amplification factor of via node; S ₀Refer to when given bit position is 0 corresponding QAM modulation constellation points; S1 refers to when particular bit position is 1, corresponding QAM modulation constellation points.S then represents all constellation point that the QAM modulation comprises.

9. method according to claim 7, wherein, described via node comprises the processing that the signal that receives carries out coding Network Based: described via node is eliminated noise and modulation treatment again to the signal that receives; Wherein, described noise is eliminated and is adopted following formula to realize $(S_{\min }^{\left(1\right)},S_{\min }^{\left(2\right)})=\underset{x_1\&Element;S^{\left(1\right)},x_2\&Element;S^{\left(2\right)}}{\arg }\min (y_r-g_1\&CenterDot;x_1-g_2\&CenterDot;x_2);$ Described again modulation treatment comprises: via node is obtaining

Afterwards, according to

Determine the first mobile terminal MS 1 and the second position of mobile terminal MS 2 symbol that sends in the constellation table in the second mixed signal of receiving

And then utilize and compare S ⁽¹⁾And S ⁽²⁾More the constellation table of high order modulation is modulated the second mixed signal that receives again, and generates x _rAnd forward;

Described joint-detection comprises: described base station utilizes following formula to obtain the log-likelihood ratio of each bit that signal comprises that portable terminal sends in self coverage:

$\mathrm{LLR}\left(b_i\right)=\log \left(\frac{\underset{x_1\&Element;S_0,x_2\&Element;S}{\mathrm{\&Sigma;}}P(y_1\left(1\right),y_1\left(2\right)/x_1,x_2)}{\underset{x_1\&Element;S_1,x_2\&Element;S}{\mathrm{\&Sigma;}}P(y_1\left(1\right),y_1\left(2\right)/x_1,x_2)}\right)$

Wherein, P (y ₁(1), y ₁(2)/x ₁, x ₂)=P (y ₁(1)/x ₁, x ₂) P (y ₁(2)/x ₁, x ₂), P (y ₁(1)/x ₁, x ₂), P (y ₁(2)/x ₁, x ₂) calculate by following formula:

$P(y_1\left(1\right)/x_1,x_2)=\frac{1}{\mathrm{\&pi;}{N}_0}\exp \{-\frac{{\left|\right|y_1\left(1\right)-h_{11}{x}_1-h_{21}{x}_2\left|\right|}^2}{\left|\right|N_0\left|\right|}\}$

$P(y_1\left(2\right)/x_1,x_2)=P(y_1\left(2\right)/x_r)=\frac{1}{\mathrm{\&pi;}{N}_0}\exp \{-\frac{{\left|\right|y_1\left(2\right)-g_3{x}_r\left|\right|}^2}{\left|\right|N_0\left|\right|}\}$

Wherein, y ₁(1) represents the first mixed signal that the first base station BS 1 receives at the first time slot; y ₁(2) represent the 3rd mixed signal that the first base station BS 1 receives at the second time slot; y _rRepresent the second mixed signal that via node receives at the first time slot; h ₁₁Represent the signal impulse response of the channel of the first mobile terminal MS 1 to first base station BS 1; h ₂₁Represent the signal impulse response of the channel of the second mobile terminal MS 2 to first base station BSs 1; x ₁And x ₂Represent respectively the signal that the first mobile terminal MS 1 and the second mobile terminal MS 2 send at the first time slot; x _rThe second mixed signal after representative is processed; g ₁And g ₂Represent respectively the first mobile terminal MS 1 and the second mobile terminal MS 2 to the signal impulse response of the channel of via node; g ₃Represent via node to the signal impulse response of the channel of the first base station BS 1; N ₀Represent the power spectral density of noise; S ₀Refer to when given bit position is 0 corresponding QAM modulation constellation points; S ₁Refer to when particular bit position is 1 corresponding QAM modulation constellation points.S then represents all constellation point that the QAM modulation comprises; S ⁽¹⁾And S ⁽²⁾Represent respectively the modulation constellation table that the first mobile terminal MS 1 and the second mobile terminal MS 2 adopt;

With

Represent respectively the symbol that the first mobile terminal MS 1 that via node estimates and the second mobile terminal MS 2 send.

10. method according to claim 7, wherein, described via node comprises the processing that the signal that receives carries out coding Network Based: the signal that receives is eliminated noise to described via node and compression is processed; Wherein, described noise is eliminated and is adopted following formula to realize $(S_{\min }^{\left(1\right)},S_{\min }^{\left(2\right)})=\underset{x_1\&Element;S^{\left(1\right)},x_2\&Element;S^{\left(2\right)}}{\arg }\min (y_r-g_1\&CenterDot;x_1-g_2\&CenterDot;x_2);$ Described compression is processed and comprised: via node is obtaining Afterwards, according to Determine the first mobile terminal MS 1 and the second position of mobile terminal MS 2 symbol that sends in the constellation table in the second mixed signal of receiving

And then according to formula $x_r=S^{\left(1\right)}\left({\mathrm{index}}_{\min }^{\left(1\right)}\right)+S^{\left(2\right)}\left({\mathrm{index}}_{\min }^{\left(2\right)}\right)$ Carry out constellation mapping, generate x _rAnd forward;

Described joint-detection comprises: described base station utilizes following formula to obtain the log-likelihood ratio of each bit that signal comprises that portable terminal sends in self coverage:

$\mathrm{LLR}\left(b_i\right)=\log \left(\frac{\underset{x_1\&Element;S_0,x_2\&Element;S}{\mathrm{\&Sigma;}}P(y_1\left(1\right),y_1\left(2\right)/x_1,x_2)}{\underset{x_1\&Element;S_1,x_2\&Element;S}{\mathrm{\&Sigma;}}P(y_1\left(1\right),y_1\left(2\right)/x_1,x_2)}\right)$

Wherein, P (y ₁(1), y ₁(2)/x ₁, x ₂)=P (y ₁(1)/x ₁, x ₂) P (y ₁(2)/x ₁, x ₂), P (y ₁(1)/x ₁, x ₂), P (y ₁(2)/x ₁, x ₂) calculate by following formula:

$P(y_1\left(1\right)/x_1,x_2)=\frac{1}{\mathrm{\&pi;}{N}_0}\exp \{-\frac{{\left|\right|y_1\left(1\right)-h_{11}{x}_1-h_{21}{x}_2\left|\right|}^2}{\left|\right|N_0\left|\right|}\}$

$P(y_1\left(2\right)/x_1,x_2)=P(y_1\left(2\right)/x_r)=\frac{1}{\mathrm{\&pi;}{N}_0}\exp \{-\frac{{\left|\right|y_1\left(2\right)-g_3{x}_r\left|\right|}^2}{\left|\right|N_0\left|\right|}\}$

Wherein, y ₁(1) represents the first mixed signal that the first base station BS 1 receives at the first time slot; y ₁(2) represent the 3rd mixed signal that the first base station BS 1 receives at the second time slot; y _rRepresent the second mixed signal that via node receives at the first time slot; h ₁₁Represent the signal impulse response of the channel of the first mobile terminal MS 1 to first base station BS 1; h ₂₁Represent the signal impulse response of the channel of the second mobile terminal MS 2 to first base station BSs 1; x ₁And x ₂Represent respectively the signal that the first mobile terminal MS 1 and the second mobile terminal MS 2 send at the first time slot; x _rThe second mixed signal after representative is processed; g ₁And g ₂Represent respectively the first mobile terminal MS 1 and the second mobile terminal MS 2 to the signal impulse response of the channel of via node; g ₃Represent via node to the signal impulse response of the channel of the first base station BS 1; N ₀Represent the power spectral density of noise; S ₀Refer to when given bit position is 0 corresponding QAM modulation constellation points; S ₁Refer to when particular bit position is 1 corresponding QAM modulation constellation points.S then represents all constellation point that the QAM modulation comprises; S ⁽¹⁾And S ⁽²⁾Represent respectively the modulation constellation table that the first mobile terminal MS 1 and the second mobile terminal MS 2 adopt;

With

Represent respectively the symbol that the first mobile terminal MS 1 that via node estimates and the second mobile terminal MS 2 send.

11. to the described method of 10 any one claims, wherein, the method further comprises according to claim 1: the portable terminal pair of determining the associating data retransmission.

12. method according to claim 11, wherein, the described portable terminal of determining the associating data retransmission is to comprising:

Portable terminal is measured the reference signal of this residential quarter and neighbor cell;

If the difference of the reference signal strength of this residential quarter and neighbor cell is less than predefined reference signal thresholding, then this portable terminal is reported the direct transfer channel condition of link of the identify label of neighbor cell and this residential quarter to this cell base station;

Base station notice portable terminal is measured the reference signal of this residential quarter of transmitting via conversion link;

Portable terminal obtains the channel condition of conversion link according to the reference signal of this residential quarter of transmitting via conversion link that measures, and the channel condition of conversion link is reported this cell base station;

Judge according to the direct transfer channel condition of link and the channel condition of conversion link of this residential quarter whether the quality of conversion link is better than the link that direct transfers, if so, then this portable terminal is added in alternate list; And

Select at random portable terminal in self alternate list and a portable terminal in the neighbor cell alternate list as the portable terminal of uniting data retransmission pair.

13. method according to claim 11, wherein, the described portable terminal of determining the associating data retransmission is to comprising:

Via node is monitored the reference signal that the neighbor cell portable terminal sends;

If difference from the reference signal strength of the portable terminal of two residential quarters is arranged less than predetermined the first thresholding, and the reference signal strength of described portable terminal from two residential quarters is all greater than predetermined the second thresholding, and then via node is notified base station to described two residential quarters with the reference signal form of described portable terminal from two residential quarters;

The identify label of the portable terminal of above-mentioned two residential quarters is determined respectively in the base station of described two residential quarters according to the reference signal form that receives, and the portable terminal that this identify label is corresponding adds in the alternate list of self; And

Select at random portable terminal in self alternate list and a portable terminal in the neighbor cell alternate list as the portable terminal of uniting data retransmission pair.

14. according to claim 1 to the described method of 10 any one claims, wherein, described via node is realized by the base station of current free time.

15. a via node is characterized in that, comprising:

The mixed signal receiving element is used in the mixed signal of the first time slot reception from portable terminal;

The mixed signal processing unit is used for the mixed signal that receives is carried out the processing of coding Network Based; And

The mixed signal retransmission unit, the mixed signal that is used for after the second time slot will be processed is forwarded to the base station that is adjacent.

16. a base station is characterized in that, comprising:

The joint-detection unit, be used for obtaining the log-likelihood ratio of interior portable terminal each bit that signal transmitted comprises of self coverage to carrying out joint-detection from the direct mixed signal that receives of portable terminal and at the second time slot from the mixed signal that via node receives at the first time slot;

Decoder is deciphered according to the log-likelihood ratio of portable terminal each bit that signal transmitted comprises in self coverage, obtains portable terminal signal transmitted in self coverage.

Images