CN103414505B - A kind of LTE femtocell user matching method that there is pattern and switch - Google Patents

Abstract

The present invention discloses a kind of LTE femtocell user matching method having pattern and switch, and carries out user's pairing by dispatching cycle, adopts each dispatching cycle polling method to choose first user of a unpaired femtocell user HUE as pairing user group; Select match with HUE in layer according to cross-layer interference size or cross-layer is matched with macro base station user MUE, under the prerequisite of guarantee bit error rate, carry out maximization match; Pairing completes, and Home eNodeB notifies that all participations pairing user sends data in next dispatching cycle.The present invention adopt the mode of signal interference ratio threshold determination adaptively selected with the layer of HUE in match or match with the cross-layer of MUE, not exceeding when bit error rate increases control coefrficient of average error bit rate continues to increase pairing user, further increase the channel utilization of limited frequency band, under the prerequisite ensureing the error rate, Home eNodeB is utilized to alleviate macro base station operating pressure.

Description

A kind of LTE femtocell user matching method that there is pattern and switch

Technical field

The present invention relates to wireless communication receiver technical field, be specifically related to a kind of LTE femtocell user matching method that there is pattern and switch.

Background technology

According to investigations, the speech business more than 50% and the data service more than 70% occur in indoor environment, comprise family, office, coffee shop, shopping square etc.But due to the penetration loss of wall, macro base station network is difficult to the demand meeting indoor communications well.For addressing this problem, the technology of the auxiliary macro base station communication of Home eNodeB (femtocell) is utilized to arise at the historic moment.Home eNodeB, also known as Femto cell, is called HomeeNodeB in LTE system, is called for short HeNB.Home eNodeB is a kind of compact low power base station, and coverage is 10-50m, is mainly used in solving in-door covering problem, has the features such as access is simple, low-power consumption, low cost.Home eNodeB is linked into the network of telecom operators by the wide band system such as Digital Subscriber Line or optical fiber.

The number of users of Home eNodeB support is 4 to 8.Virtual multiple-input and multiple-output (VirtualMIMO, VirtualMultipleInputMultipleOutput) technology is adopted in the transmission of up link.Single antenna by multiple different user is combined, and the same time transmits, and forms virtual MIMO with many reception antennas of Home eNodeB, and being just equivalent to unique user at receiving terminal transmitting terminal, to be configured with multiple antennas the same, therefore be called virtual MIMO.Since virtual MIMO allows different user transmit simultaneously, the different systematic function that so different user's matching methods just can produce.In addition, the frequency resource allocation scheme due to current industry extensive concern is part channel configuration, i.e. macro base station (MeNB) and Home eNodeB common sparing frequency band altogether, and common-channel interference becomes a problem demanding prompt solution.When HeNB and MeNB works on the same frequency band, macro base station user (MUE) can cause interference to HeNB.HeNB receiver, except receiving the useful signal of femtocell user (HUE), also can receive the interference signal from MUE, be called that cross-layer is disturbed.When the transmitting power of MUE less to such an extent as to negligible to the interference of HeNB time, the main co-channel interference considering that in femtocell, each HUE is mutual, carries out user's pairing, is called for short pairing in layer here between HUE; When MUE power is comparatively large and produce comparatively strong jamming to HeNB, now must consider cross-layer interference problem from MUE and between HUE and MUE, carry out user's pairing, being called for short cross-layer pairing.Therefore, the marriage problem studying user in Home eNodeB is necessary.HeNB user's matching method that is excellent, interference adaptive, is very significantly improved making the error rate of system (BER) performance.

Summary of the invention

Goal of the invention: the object of the invention is to overcome the deficiencies in the prior art provides a kind of LTE femtocell user matching method having pattern and switch.

Technical scheme: the LTE femtocell user matching method that there is pattern and switch of the present invention, carry out user's pairing by dispatching cycle, each dispatching cycle performs following steps:

(1) polling method is adopted to choose first user of a unpaired femtocell user HUE as pairing user group;

(2) select to match with HUE in layer according to cross-layer interference size or cross-layer and macro base station user MUE match;

(3) the number of users N of pairing user group has more been added _qwith reception antenna number N _rsize, if N _q< N _r, perform step (4); Otherwise perform step (5);

(4) the growth rate η (i) comparing pairing user average error bit rate increases control coefrficient η with bit error rate _csize, if η (i)≤η _c, make i=i+1 and continue next round pairing by cross-layer pairing; Otherwise perform step (5);

(5) matched, Home eNodeB notifies that all participations pairing user sends data in next dispatching cycle.

First user of pairing user group matches the corresponding element of the vectorial Q of instruction (1) in step (1) wherein n ₁represent that the HUE be selected is at all N ₀sequence number in individual HUE user;

The method that SA-BPS algorithm finds pairing antenna sets is as follows:

Wherein, Q is the pairing instruction vector of N × 1, and N comprises all numbers of users of HUE and MUE in Home eNodeB; it is the set of all possible instruction vector; represent the change of user's average error bit rate in whole pairing process, q _nfor nth user matches the corresponding element indicating vectorial Q (n).

The n-th element q of the vectorial Q of pairing instruction _nmeet: if the antenna of nth user is selected as pairing, then q _n=1, otherwise, q _n=0; Also need to satisfy condition:

$\underset{n=1}{\overset{N}{\mathrm{\&Sigma;}}}{q}_n\&le;N_R,q_n\&Element;\left\{\mathrm{0,1}\right\}$

N _rthe quantity of Home eNodeB reception antenna.

represent the change of user's average error bit rate in whole pairing process, it meets following formula:

$\mathrm{\&Delta;}\stackrel{\&OverBar;}{\mathrm{BER}}=\underset{i=2}{\overset{N_T}{\mathrm{\&Sigma;}}}\mathrm{\&Delta;}\stackrel{\&OverBar;}{\mathrm{BER}\left(i\right)}$

Wherein, N _trepresent the antenna amount participating in pairing when having matched. represent i-th take turns and find pairing antenna terminates after, matched the change of antenna average error bit rate, η (i) represents and has matched the rate of change of antenna average error bit rate, and they can be expressed as:

$\mathrm{\&Delta;}\stackrel{\&OverBar;}{\mathrm{BER}\left(i\right)}=\stackrel{\&OverBar;}{\mathrm{BER}\left(i\right)}-\stackrel{\&OverBar;}{\mathrm{BER}(i-1)}$

$\mathrm{\&eta;}\left(i\right)=\frac{\mathrm{\&Delta;}\stackrel{\&OverBar;}{\mathrm{BER}\left(i\right)}}{\stackrel{\&OverBar;}{\mathrm{BER}(i-1)}}$

Wherein, represent i-th take turns and find pairing antenna completes after, matched the average error bit rate of antenna, can be expressed as:

$\stackrel{\&OverBar;}{\mathrm{BER}\left(i\right)}=\frac{1}{i}\underset{j=1}{\overset{i}{\mathrm{\&Sigma;}}}{\mathrm{BER}}_{n_J}\left(i\right)$

Wherein, after expression i-th is taken turns and found pairing antenna, in i the user matched, the bit error rate of a jth user.It meets formula below:

${\mathrm{BER}}_{n_j}\left(i\right)=\frac{N_{\min }}{{\log }_2{M}_0}Q\left(\sqrt{\mathrm{\&xi;}\&CenterDot;{\mathrm{SINR}}_{n_j}\&CenterDot;G_c}\right)$

Wherein N _minrefer to the mean value of the adjacent constellation point quantity of each constellation point in modulation figure.M ₀represent the number of constellation point in modulation figure.Coefficient ξ=3/ (R (M ₀-1)), wherein R represents code check.G _cfor channel coding gain. for without inclined Signal to Interference plus Noise Ratio, be expressed as:

${\mathrm{SINR}}_{n_j}=\frac{{\mathrm{\&sigma;}}_{a_{n_j}}^2}{{\mathrm{\&sigma;}}_{e_{n_j}}^2}-1$

Wherein, it is the variance of signal. be the variance of error, meet formula below:

${\mathrm{\&sigma;}}_{e_{n_j}}^2=\frac{1}{M}\underset{m=0}{\overset{M-1}{\mathrm{\&Sigma;}}}{\mathrm{\&Sigma;}}_{n_j{n}_j}^2\left[m\right]$

Wherein, 1≤j≤i, intermediate variable meet following formula:

$\left[\begin{array}{cccc}{\mathrm{\&Sigma;}}_{n_1{n}_1}^2\left[m\right]& {\mathrm{\&Sigma;}}_{n_1{n}_2}^2\left[m\right]& ...& {\mathrm{\&Sigma;}}_{n_1{n}_i}^2\left[m\right]\\ {\mathrm{\&Sigma;}}_{n_2{n}_1}^2\left[m\right]& {\mathrm{\&Sigma;}}_{n_2{n}_2}^2\left[m\right]& ...& {\mathrm{\&Sigma;}}_{n_2{n}_i}^2\left[m\right]\\ ...& ...& ...& ...\\ {\mathrm{\&Sigma;}}_{n_i{n}_1}^2\left[m\right]& {\mathrm{\&Sigma;}}_{n_i{n}_2}^2\left[m\right]& ...& {\mathrm{\&Sigma;}}_{n_i{n}_i}^2\left[m\right]\end{array}\right]={\mathrm{\&sigma;}}_n^2{\left(H^H\right[m\left]H\right[m]+\frac{{\mathrm{\&sigma;}}_n^2}{{\mathrm{\&sigma;}}_{a_{n_j}}^2})}^{-1}$

Wherein 0≤m≤M – 1, M is number of subcarriers.H [m] i-th takes turns in pairing, participates in the frequency domain channel matrix of user on subcarrier m of pairing, it is noise variance.

It is as follows that step (2) chooses matching method:

When actual signal interference ratio selects pairing mode in layer higher than Home eNodeB during critical signal interference ratio, namely Home eNodeB is chosen a user and is added pairing user group in unpaired HUE, makes average error bit rate growth minimize; After choosing user, the element in the vectorial Q (i) of order pairing instruction wherein n _ithe sequence number of the HUE selected by pairing is taken turns in expression i-th;

When actual signal interference ratio selects cross-layer pairing mode lower than Home eNodeB during critical signal interference ratio, namely Home eNodeB is chosen a user and is added pairing user group in unpaired MUE, makes average error bit rate growth minimize; After choosing user, the element in the vectorial Q (i) of order pairing instruction wherein n _ithe sequence number of the MUE selected by pairing is taken turns in expression i-th.

N in step (3) _qneed meet:

$N_q=\underset{n=1}{\overset{N_0}{\mathrm{\&Sigma;}}}{q}_n=\underset{j=1}{\overset{i}{\mathrm{\&Sigma;}}}{q}_{n_j}.$

N _qfor adding the number of users of pairing user group, N ₀represent the quantity of all HUE users in HeNB, q _nfor nth user matches the corresponding element indicating vectorial Q (n).

Beneficial effect: 1, the present invention adopt the mode of signal interference ratio threshold determination adaptively selected with the layer of HUE in match or match with the cross-layer of MUE, not exceeding when bit error rate increases control coefrficient of average error bit rate continues to increase pairing user, further increase the channel utilization of limited frequency band, under the prerequisite ensureing the error rate, Home eNodeB is utilized to alleviate macro base station operating pressure.2, the pairing of poll matching method is adopted to ensure that user can not be missed.3, according to the change related algorithm pointing to user's average error bit rate in vectorial Q and pairing process, determine whether match with next user by pointing to vectorial Q, the change of direct reaction average error bit rate and the relation of pairing user, average error bit rate can be controlled in threshold value.4, an assembly should be no more than the whole reception antennas in user's group to user, to prevent extraneous clutter frequency interferences.5, selecting to match in layer cross-layer by actual signal interference ratio and critical signal interference ratio relation matches more directly perceived, more succinct in flow process.6, added pairing user group number of users with sensing vector be 1 user gather identical, calibrate pairing further, guaranteeing can not by other extraneous clutter frequency interferences.

Accompanying drawing explanation

Fig. 1 is the LTE femtocell user pairing algorithm flow chart with pattern switching;

Fig. 2 is that interference power obeys [P _m– 5, P _m+ 5] the pattern performance of handoffs under scene is uniformly distributed;

Fig. 3 is that interference power obeys [P _m– 10, P _m+ 10] the pattern performance of handoffs under scene is uniformly distributed;

Fig. 4 is that interference power obeys [P _m– 20, P _m+ 20] the pattern performance of handoffs under scene is uniformly distributed.

Embodiment

Below technical solution of the present invention is described in detail, but protection scope of the present invention is not limited to described embodiment.

Embodiment 1

The LTE femtocell user matching method having pattern and switch of the present invention, carries out user's pairing by dispatching cycle.In the simulating scenes of embodiment, between HeNB and MeNB, have employed the mutual exchange channel information of CoMP technology and scheduling decision information.Suppose that the quantity of HUE and MUE is 8.Simulating scenes is set to the low channel relevancy scene of femtocell.Other simulation parameter is in table 1.

Table 1 simulation parameter

Parameter	Arrange
		HUE quantity	8
MUE quantity	8
		The number of transmit antennas of HUE	1
The reception antenna number of HeNB	2
		System bandwidth	20MHz
Subcarrier spacing	15kHz
		Sample frequency	30.72MHz
Carrier frequency	2GHz
		Total sub-carrier number	2048

User's sub-carrier number	1200
		Channel model	Based on the femtocell channel of 3GPP EPA
The modulation system of pairing in layer	QPSK
		The modulation system of cross-layer pairing	16QAM
Coded system	Turbo 1/3
		Channel estimating	Desirable
Noise power	-14dB
		Bit error rate increases control coefrficient	0.1

Under different cross-layer interference power condition, get the data of a dispatching cycle respectively compare, each dispatching cycle performs following steps:

(1) polling method is adopted to choose first user of a unpaired femtocell user HUE as pairing user group;

(2) select to match with HUE in layer according to cross-layer interference size or cross-layer and macro base station user MUE match;

(3) the number of users N of pairing user group has more been added _qwith reception antenna number N _rsize, if N _q< N _r, perform step (4); Otherwise perform step (5);

(4) the growth rate η (i) comparing pairing user average error bit rate increases control coefrficient η with bit error rate _csize, if η (i)≤η _c, make i=i+1 and continue next round pairing by cross-layer pairing; Otherwise perform step (5);

(5) matched, Home eNodeB notifies that all participations pairing user sends data in next dispatching cycle.

Fig. 2, Fig. 3 and Fig. 4 are the simulation performance figure that different cross-layer interference power divides the pairing algorithm pattern switching planted.In Fig. 2, Fig. 3 and Fig. 4, the cross-layer interference power of each MUE all meets and to be uniformly distributed and average is all P _m=0dB, but variance is different, and in three kinds of simulating scenes, the distributed area of cross-layer interference power is respectively [P _m– 5, P _m+ 5], [P _m– 10, P _m+ 10] and [P _m– 20, P _m+ 20], unit is dB, and its value and power reference is the average transmit power of HUE.In three analogous diagram, obtain different critical signal interference ratios be respectively 12dB, 17.5dB and 23.8dB.Namely when actual signal interference ratio is greater than critical signal interference ratio, HeNB selects pairing mode in layer, and when actual signal interference ratio is less than critical signal interference ratio, HeNB switches to cross-layer pairing mode.Carry out pairing mode switching by this way, system can be made under the prerequisite ensureing performance of BER to obtain higher matching efficiency.

As mentioned above, although represented with reference to specific preferred embodiment and described the present invention, it shall not be construed as the restriction to the present invention self.Under the spirit and scope of the present invention prerequisite not departing from claims definition, various change can be made in the form and details to it.

Claims (4)

1. have the LTE femtocell user matching method that pattern switches, it is characterized in that: carry out user's pairing by dispatching cycle, each dispatching cycle performs following steps:

(1) polling method is adopted to choose first user of a unpaired femtocell user HUE as pairing user group;

(2) select to match with HUE in layer according to cross-layer interference size or cross-layer and macro base station user MUE match; Choose matching method as follows:

When actual signal interference ratio selects pairing mode in layer higher than Home eNodeB during critical signal interference ratio, namely Home eNodeB is chosen a user and is added pairing user group in unpaired HUE, makes average error bit rate growth minimize; After choosing user, the element in the vectorial Q (i) of order pairing instruction wherein n _ithe sequence number of the HUE selected by pairing is taken turns in expression i-th;

When actual signal interference ratio selects cross-layer pairing mode lower than Home eNodeB during critical signal interference ratio, namely Home eNodeB is chosen a user and is added pairing user group in unpaired MUE, makes average error bit rate growth minimize; After choosing user, the element in the vectorial Q (i) of order pairing instruction wherein n _ithe sequence number of the MUE selected by pairing is taken turns in expression i-th;

(3) the number of users N of pairing user group has more been added _qwith reception antenna number N _rsize, if N _q<N _r, perform step (4); Otherwise perform step (5);

(4) the growth rate η (i) comparing pairing user average error bit rate increases control coefrficient η with bit error rate _csize, if η (i)≤η _c, make i=i+1 and continue next round pairing by cross-layer pairing; Otherwise perform step (5);

(5) matched, Home eNodeB notifies that all participations pairing user sends data in next dispatching cycle.

2. there is LTE femtocell user matching method that pattern switches according to claim 1, it is characterized in that: first user of pairing user group matches the corresponding element of the vectorial Q of instruction (1) in step (1) wherein n ₁represent that the HUE be selected is at all N ₀sequence number in individual HUE user;

The method that SA-BPS algorithm finds pairing antenna sets is as follows:

Wherein, Q is the pairing instruction vector of N × 1, and N comprises all numbers of users of HUE and MUE in Home eNodeB; it is the set of all possible instruction vector; represent the change of user's average error bit rate in whole pairing process, q _nfor nth user matches the corresponding element indicating vectorial Q (n).

3. there is LTE femtocell user matching method that pattern switches according to claim 2, it is characterized in that: the n-th element q of the vectorial Q of described pairing instruction _nmeet: if the antenna of nth user is selected as pairing, then q _n=1 otherwise, q _n=0; Also need to satisfy condition:

$\underset{n=1}{\overset{N}{\&Sigma;}}{q}_n\&le;N_R,q_n\&Element;\left\{0,1\right\}$

N _rthe quantity of Home eNodeB reception antenna.

4. there is LTE femtocell user matching method that pattern switches according to claim 1, it is characterized in that: N in step (3) _qneed meet:

$N_q=\underset{n=1}{\overset{N_0}{\&Sigma;}}{q}_n=\underset{j=1}{\overset{i}{\&Sigma;}}{q}_{n_j}$

N _qfor adding the number of users of pairing user group, N ₀represent the quantity of all HUE users in HeNB, q _nfor nth user matches the corresponding element indicating vectorial Q (n).