CN102802241B - The system of selection of a kind of high energy efficiency wireless relay - Google Patents

Abstract

The invention discloses the system of selection of a kind of high energy efficiency wireless relay, its main practice is: be in park mode without the base station of access user or relay station; When user asks connecting system, base station is according to channel condition information, the access user list of relay station, the access user list of base station self, when meeting minimum signal to noise ratio and requiring, pick out the information that the maximum corresponding relay station of link efficiency U forwards this user, base station, the relay station selected adopt mode of operation, trunking traffic link establishment; If it is maximum that efficiency U is directly transmitted in base station, then adopt base station directly to transmit, base station adopts mode of operation, and the communication link that direct transfers is set up; This user that communicated leaves, if again without other access users on base station or selected relay station, then base station or this relay station proceed to park mode.The method while guaranteeing QoS of customer, the efficiency of elevator system greatly, and greatly can reduce algorithm complex.

Description

The system of selection of a kind of high energy efficiency wireless relay

Technical field:

The invention belongs to the resource management techniques field of relay system in wireless communication system, be specially the system of selection of a kind of high energy efficiency wireless relay.

Background technology

Along with in cordless communication network, the proportion of data service continues to increase, and growing data and immanent access demand cause the sharply expansion of network infrastructure, bring huge energy ezpenditure thereupon.While guarantee cordless communication network capacity increases, restriction power consumption has become an urgent demand of mobile operator.So will while guaranteeing service quality, elevator system efficiency as much as possible, and efficiency is main relevant with the power consumption of system with the throughput of system.

Up to now, the research about wireless network efficiency is weighed based on power output usually.This energy performance index is merely able to the sub-fraction reflecting wireless network overall power, and this may cause imperfect and potential misleading conclusion.For assessing the efficiency of wireless network, needing the power that electronic loop and power amplifier consume to consider in efficiency problem and going.

For solving cell boarder covering problem and border problem rate, in IEEE 802.16m and LTE-Advanced standard, introduce relaying technique, but also mean high energy consumption while two-forty, and the introducing of relay station too increasing energy consumption equipment.And the result of relay selection can cause very large impact to the performance of system.By finding the retrieval of existing patent and correlation technique, existing relay selection method has:

(1) a kind of relay selection for Two-body vibrator and power distribution method (CN1589053A) are by measuring base station to each relay station and each relay station to the path loss of each user; According to path loss, the relay station that each user selects double bounce path loss sum minimum is its service, and measures the disturbed condition after this relay station of access.Last based on relay selection result and interference, the power of self-adjusted block transmitting terminal and selected relay station, thus obtain higher power system capacity, and reduce implementation complexity and signalling loads.But raising capacity also means raising power, efficiency might not get a promotion, and carries out relay selection judgement with path loss, although simply, have ignored other the impact such as channel shadow fading, therefore can not get good performance.

(2) a kind of relay selection method (CN102202382A) reducing transmitting power devises a simple relay selection method, under the prospect ensureing designing requirement outage probability, reduce system emission power largely, but in this design, each relay station can only be a source node forwarding information, different from the access situation of the relay station in Cellular Networks simultaneously.And the method just reduces power based on outage probability, but do not ensure user rate requirements, therefore its community efficiency is on the low side.

(3) wireless communication system, relay selection method, wireless relay apparatus and base station (CN101951660A), a kind of relay selection method and relay control system (CN102469017A) two patent stress to reduce the signaling consumption in relay selection.Candidate relay is only allowed to return relevant channel condition information to base station in patent CN101951660A, instead of whole channel condition information.Establishing relay services historical record in patent CN102469017A and carry out alternative routing selection, without the need to carrying out qos measurement end to end again, reducing signaling and bandwidth consumption thus.But these patents all do not consider the impact of relay selection on the performance such as capacity and power.

In a word, existing relay selection method, mostly based on this more single targets such as capacity, reduction interruption rate, reduction transmitting powers.Do not consider throughput and power two aspect, the i.e. multi-target method of efficiency simultaneously.Because circuit power consumption makes the performance of the distribution of user to relay selection also have a great impact.Especially in non-uniform Distribution community, a large amount of users is concentrated near certain site (base station or relay station), considerably less user is then only had near certain site, now adopt existing relay selection scheme, the energy consumption of system can be made greatly to increase, and throughput is not effectively promoted.

Summary of the invention:

The object of the invention is to propose the system of selection of a kind of high energy efficiency wireless relay, the method while guaranteeing QoS of customer, the efficiency of elevator system greatly, and greatly can reduce algorithm complex.

The technical solution adopted for the present invention to solve the technical problems is, the system of selection of a kind of high energy efficiency wireless relay, comprises the following steps:

1) in a relaying cellular cell, when base station and all relay stations are without access user, then base station and all relay stations are all in park mode; When base station is in mode of operation, and when partly or entirely relay station is without access user, then the relay station without access user is all in park mode; Under mode of operation and park mode, base station and relay station all can regular pilot signal transmitteds;

2) when user asks connecting system, user is to base station feedback channel condition information, and relay station is to base station feedback channel condition information and the access user list of self; Base station is according to channel condition information, the access user list of the access user list of relay station and base station self, when meeting minimum signal to noise ratio and requiring, pick out the information that the maximum corresponding relay station of link efficiency U forwards this user, base station and the relay station selected adopt mode of operation, trunking traffic link establishment; If it is maximum that efficiency U is directly transmitted in base station, then adopt base station directly to transmit, base station adopts mode of operation, and the communication link that direct transfers is set up; This user that communicated leaves, if again without other access users on base station or selected relay station, then base station or this relay station proceed to park mode; Efficiency U wherein, $U=\frac{R\·T_{\mathrm{link}}}{({\mathrm{Pc}}_B+{\mathrm{Pc}}_R+P_B/{\mathrm{\ζ}}_B+P_R/{\mathrm{\ζ}}_R)\·T_{\mathrm{hop}}},$ In formula, R is total speed, Pc _b, Pc _rthat base station and relay station adopt and proceed to circuit power consumption that mode of operation increases (if before this user access, base station or relay station are in mode of operation, then Pc from park mode respectively _b=0 or Pc _r=0), P _b, P _rthe transmitted power of base station and relay station respectively, ζ _b, ζ _r∈ [0,1] is the power amplifier efficiency of base station and relay station respectively, T _linkfor the overall transmission time of whole link, T _hopthe overall transmission time of every hop link.

Compared with prior art, the invention has the beneficial effects as follows:

One, meeting under minimum received signal to noise ratio requirement, the efficiency calculated with the total energy consumption comprising circuit loss carries out relay selection for target, and the relay station not having user to access, adopt park mode; Can ensure high transmission rate, save energy really to greatest extent again, the efficiency of system is high.Especially for the scene of user's non-uniform Distribution, have more relay station and be in park mode, in raising efficiency, have more advantage.

Two, relay selection is carried out to the user of request access one by one for the access situation of current area in base station, instead of multi-user calculates selection simultaneously, and its algorithm complex is low, is easy to realize.

Above-mentioned relay station is amplification forwarding relay station or decode-and-forward relay station, and the frame structure of relay system comprises 2 subframes, therefore adopts 2 subframes to carry out transfer of data during relay transmission, and the length of each subframe is the overall transmission time T of constant T second, whole link _link=2Tx, x represent the frame number that this access user is required within whole service time; Base station only adopts first subframe and user to transmit data, the overall transmission time T of whole link _link=Tx; The overall transmission time T of every hop link _hop=Tx; Base station assigns is constant N to access user carrier number, and every frame transmitting energy is constant P _kt joule;

During relay transmission, the transmitted power of base station is P _bwatt, the transmitted power of relay station is P _k-P _bwatt, then R=Rr (P _b), the maximum U of repeated link efficiency U _max,

$U_{\max }=\underset{P_B}{\max }\frac{\mathrm{Rr}\left(P_B\right)\·T_{\mathrm{link}}}{({\mathrm{Pc}}_B+{\mathrm{Pc}}_R+P_B/{\mathrm{\ζ}}_B+(P_K-P_B)/{\mathrm{\ζ}}_R)\·T_{\mathrm{hop}}},$ s.t.Sr(P _B)≥r

Wherein Rr (P _b) for base-station transmitting-power be P _btime the total speed of repeated link, r is the minimum signal to noise ratio requirement of current access user, Sr (P _b) for base-station transmitting-power be P _btime obtainable repeated link signal to noise ratio;

When base station is directly transmitted, the transmitted power of base station is P _b=P _k, then P _k-P _b=0, Pc _r=0, R=Rd (P _k); The efficiency U of link of direct transferring is U _d,

$U_d=\frac{\mathrm{Rd}\left(P_K\right)\·T_{\mathrm{link}}}{({\mathrm{Pc}}_B+P_K/{\mathrm{\ζ}}_B)\·T_{\mathrm{hop}}},$ s.t.Sd(P _K)≥r

Wherein Rd (P _k) for base-station transmitting-power be P _ktime the total speed of the link that direct transfers, Sd (P _k) for base-station transmitting-power be P _ktime the obtainable link signal to noise ratio that direct transfers;

Compare the efficiency U of the link that direct transfers _dwith the efficiency maximum U of each repeated link _max, the link selecting maximum numerical value corresponding transmits.

Like this, the every frame transmitting energy distributed each access user is identical with carrier number, namely ensure that the fairness of link selection, calculates simultaneously and more simplify; When every frame transmitting energy is identical, by the adjustment of base station power and relay station power, the link of the maximum efficiency selected, further increases the efficiency of system.

Below in conjunction with the drawings and specific embodiments, the present invention is described in further detail.

Accompanying drawing explanation

Fig. 1 is relay selection method of the present invention, existing based on the relay selection method of capacity (transmission rate) and the relay selection method based on minimal path loss, and the total bit number of transmission under the minimum signal to noise ratio of difference requires compares;

Fig. 2 is relay selection method of the present invention, the existing relay selection method based on capacity and the relay selection method based on minimal path loss, under the minimum signal to noise ratio of difference requires consume gross energy and compare;

Fig. 3 is relay selection method of the present invention, the existing relay selection method based on capacity and the relay selection method based on minimal path loss, and the total energy effect under the minimum signal to noise ratio of difference requires compares;

Fig. 4 is relay selection method of the present invention, the existing relay selection method based on capacity and the relay selection method based on minimal path loss, and the interruption rate under the minimum signal to noise ratio of difference requires compares.

Embodiment

Embodiment

A kind of embodiment of the present invention is, the system of selection of a kind of high energy efficiency wireless relay, comprises the following steps:

1) in a relaying cellular cell, when base station and all relay stations are without access user, then base station and all relay stations are all in park mode; When base station is in mode of operation, and when partly or entirely relay station is without access user, then the relay station without access user is all in park mode; Under mode of operation and park mode, base station and relay station all can regular pilot signal transmitteds;

2) when user asks connecting system, user is to base station feedback channel condition information, and relay station is to base station feedback channel condition information and the access user list of self; Base station is according to channel condition information, the access user list of the access user list of relay station and base station self, when meeting minimum signal to noise ratio and requiring, pick out the information that the maximum corresponding relay station of link efficiency U forwards this user, base station and the relay station selected adopt mode of operation, trunking traffic link establishment; If it is maximum that efficiency U is directly transmitted in base station, then adopt base station directly to transmit, base station adopts mode of operation, and the communication link that direct transfers is set up; This user that communicated leaves, if again without other access users on base station or selected relay station, then base station or this relay station proceed to park mode; Efficiency U wherein, $U=\frac{R\·T_{\mathrm{link}}}{({\mathrm{Pc}}_B+{\mathrm{Pc}}_R+P_B/{\mathrm{\ζ}}_B+P_R/{\mathrm{\ζ}}_R)\·T_{\mathrm{hop}}},$ In formula, R is total speed, Pc _b, Pc _rthat base station and relay station adopt and proceed to circuit power consumption that mode of operation increases (if before this user access, base station or relay station are in mode of operation, then Pc from park mode respectively _b=0 or Pc _r=0), P _b, P _rthe transmitted power of base station and relay station respectively, ζ _b, ζ _r∈ [0,1] is the power amplifier efficiency of base station and relay station respectively, T _linkfor the overall transmission time of whole link, T _hopthe overall transmission time of every hop link.

The relay station of this example is amplification forwarding relay station or decode-and-forward relay station, and the frame structure of relay system comprises 2 subframes, therefore adopts 2 subframes to carry out transfer of data during relay transmission, and the length of each subframe is the overall transmission time T of constant T second, whole link _link=2Tx, x represent the frame number that this access user is required within whole service time; Base station only adopts first subframe and user to transmit data, the overall transmission time T of whole link _link=Tx; The overall transmission time T of every hop link _hop=Tx; Base station assigns is constant N to access user carrier number, and the energy of every frame transmission is constant P _kt joule;

During relay transmission, the transmitted power of base station is P _bwatt, the transmitted power of relay station is P _k-P _bwatt, then R=Rr (P _b), the maximum U of repeated link efficiency U _max,

$U_{\max }=\underset{P_B}{\max }\frac{\mathrm{Rr}\left(P_B\right)\·T_{\mathrm{link}}}{({\mathrm{Pc}}_B+{\mathrm{Pc}}_R+P_B/{\mathrm{\ζ}}_B+(P_K-P_B)/{\mathrm{\ζ}}_R)\·T_{\mathrm{hop}}},$ s.t.Sr(P _B)≥r

Wherein Rr (P _b) for base-station transmitting-power be P _btime the total speed of repeated link, r is the minimum signal to noise ratio requirement of current access user, Sr (P _b) for base-station transmitting-power be P _btime obtainable repeated link signal to noise ratio; When base station is directly transmitted, the transmitted power of base station is P _b=P _k, then P _k-P _b=0, Pc _r=0, R=Rd (P _k); The efficiency U of link of direct transferring is U _d,

$U_d=\frac{\mathrm{Rd}\left(P_K\right)\·T_{\mathrm{link}}}{({\mathrm{Pc}}_B+P_K/{\mathrm{\ζ}}_B)\·T_{\mathrm{hop}}},$ s.t.Sd(P _K)≥r

Wherein Rd (P _k) for base-station transmitting-power be P _ktime the total speed of the link that direct transfers, Sd (P _k) for base-station transmitting-power be P _ktime the obtainable link signal to noise ratio that direct transfers;

Compare the efficiency U of the link that direct transfers _dwith the efficiency maximum U of each repeated link _max, the link selecting maximum numerical value corresponding transmits.

The maximum U of each repeated link efficiency U above _maxconcrete computational process as follows:

First, under the requirement of minimum signal to noise ratio r, calculate the efficiency of each repeated link.To m relay station by following formula, solve the power P needed for minimum signal to noise ratio that user reaches _b.

For AF (amplification forwarding) relay station mode,

$r=\frac{P_B{\left|H_m^{\mathrm{BR}}\right|}^2\·(P_K-P_B){\left|H_m^{\mathrm{RM}}\right|}^2}{(P_B{\left|H_m^{\mathrm{BR}}\right|}^2+(P_K-P_B){\left|H_m^{\mathrm{RM}}\right|}^2+{\mathrm{\δ}}^2){\mathrm{\δ}}^2},$

For DF (decoding forwards) relay station mode,

$r=\min \{\frac{P_B{\left|H_m^{\mathrm{BR}}\right|}^2}{{\mathrm{\δ}}^2},\frac{(P_K-P_B){\left|H_m^{\mathrm{RM}}\right|}^2}{{\mathrm{\δ}}^2}\}.$

Wherein represent the path gain between base station and m relay station and between m relay station and this access user respectively, it is relevant with path loss and shadow fading; δ ²represent the power of white Gaussian noise.

Two values can be solved by above formula if for plural number or be all less than 0 or be all greater than P _k, then represent that user cannot access this relay station; If then if then therefore the power of optimum must meet if none relay station can be accessed by, then optimum relay station m ^*=0; Otherwise, if there is accessible relay station, then solve the efficiency of all accessible relay stations, because efficiency formula is at variable on, be the function of first monotonic increase monotone decreasing again.According to variable restrictive condition, utilize the slope of function can draw the relay station m that efficiency is maximum ^*and efficiency U _max.

Then, the obtainable signal to noise ratio of link that direct transfers is calculated wherein | H ^bM| ², represent path gain between base station and this access user, if α < γ, then above relay station m is selected in base station ^*for user carries out relay transmission; If m ^*=0, then this user cannot access this community.If α>=γ, then calculate the efficiency U of the link that direct transfers _d, and compare direct transfer link and selected relay station m ^*efficiency U, if the efficiency U of the link that direct transfers _dless than normal, m is then selected in base station ^*for this user carries out data retransmission, the ID of user is added base station and relay station m respectively simultaneously ^*user ID list.The efficiency U of link if direct transferred _dmaximum, base station then adopts direct transmission, the ID of user is added the user ID list of base station.

Emulation experiment:

For the relay selection algorithm that checking the present invention proposes, carry out following numerical simulation experiment.

System model is made up of 1 base station, 3 AF-relay stations and 200 users.System parameter setting is N=10, P _k=0.01 watt, Pc _b=8 watts, Pc _r=4 watts, ζ _b=ζ _r=0.5, user arrives number and obeys the Bai Song distribution that intensity is λ=0.5, obeys the exponential distribution that intensity is μ=10 service time of user.Emulation experiment shows, compare with the relay selection method based on minimal path loss with the relay selection method based on capacity, the inventive method has significant increase in efficiency and interruption rate.

Fig. 1 is relay selection method of the present invention, based on the relay selection method of capacity (transmission rate) and the relay selection method based on minimal path loss, the total bit number of transmission under the minimum signal to noise ratio of difference requires compares;

Fig. 2 is relay selection method of the present invention, based on the relay selection method of capacity and the relay selection method based on minimal path loss, under the minimum signal to noise ratio of difference requires consume gross energy and compare;

Fig. 3 is relay selection method of the present invention, based on the relay selection method of capacity and the relay selection method based on minimal path loss, the total energy effect under the minimum signal to noise ratio of difference requires compares;

Fig. 4 is relay selection method of the present invention, based on the relay selection method of capacity and the relay selection method based on minimal path loss, the interruption rate under the minimum signal to noise ratio of difference requires compares.When in Fig. 4, minimum signal to noise ratio requires as 3dB, relay selection method of the present invention and the relay selection method based on capacity, its interruption rate is 0, can't see its block diagram.And when minimum signal to noise ratio requires as 6dB, relay selection method of the present invention and the relay selection method based on capacity, its interruption rate is almost 0, and its block diagram becomes two little horizontal lines.

As can be seen from Fig. 1-4:

Based on the relay selection that capacity carries out, although the bit number of its transmission reaches maximum, its energy consumed is also more, therefore its efficiency obtained not is the highest.

And based on the relay selection method of minimal path loss, although algorithm is the simplest, but this algorithm have ignored the impact of shadow effect, and the actual total losses between two-hop link are not simple addition or are multiplied, therefore carry out relay selection with minimal path loss, not only capacity reduces, and the energy of consumption also improves, thus causes performance efficiency the poorest.

And method of the present invention is, total bit number that can transmit is a little less than the relay selection method of carrying out based on capacity, but its energy consumed is minimum, be only about 1/3 of the relay selection method energy consumption based on minimal path loss, the efficiency that can reach is maximum, about 50% is improve than the relay selection method of carrying out based on capacity, it is about 3 times of the relay selection method gained efficiency based on minimal path loss, and interruption rate is also very low, with substantially more the same than the relay selection method of carrying out based on capacity.

Claims (2)

1. a high energy efficiency wireless relay system of selection, comprises the following steps:

1) in a relaying cellular cell, when base station and all relay stations are without access user, then base station and all relay stations are all in park mode; When base station is in mode of operation, and when partly or entirely relay station is without access user, then the relay station without access user is all in park mode; Under mode of operation and park mode, base station and relay station all can regular pilot signal transmitteds;

2) when user asks connecting system, access user is to base station feedback channel condition information, and relay station is to base station feedback channel condition information and the access user list of self; Base station is according to channel condition information, the access user list of the access user list of relay station and base station self, when meeting minimum signal to noise ratio and requiring, pick out the information that the maximum corresponding relay station of link efficiency U forwards this user, base station and the relay station selected adopt mode of operation, trunking traffic link establishment; If it is maximum that efficiency U is directly transmitted in base station, then adopt base station directly to transmit, base station adopts mode of operation, and the communication link that direct transfers is set up; This user that communicated leaves, if again without other access users on base station or selected relay station, then base station or this relay station proceed to park mode; Efficiency U wherein, $U=\frac{R\&CenterDot;T_{\mathrm{link}}}{({\mathrm{Pc}}_B+{\mathrm{Pc}}_R+P_B/{\mathrm{\&zeta;}}_B+P_R/{\mathrm{\&zeta;}}_R)\&CenterDot;T_{\mathrm{hop}}},$ In formula, R is total speed, Pc _b, Pc _rthat base station and relay station adopt and proceed to the circuit power consumption that mode of operation increases, if before this user access, base station or relay station are in mode of operation, then Pc from park mode respectively _b=0 or Pc _r=0, P _b, P _rthe transmitted power of base station and relay station respectively, ζ _b, ζ _r∈ [0,1] is the power amplifier efficiency of base station and relay station respectively, T _linkfor the overall transmission time of whole link, T _hopfor the overall transmission time of every hop link.

2. method according to claim 1, is characterized in that:

Described relay station is amplification forwarding relay station or decode-and-forward relay station, and the frame structure of relay system comprises 2 subframes, adopts 2 subframes to carry out transfer of data during relay transmission, and the length of each subframe is the overall transmission time T of constant T second, whole link _link=2Tx, x represent the frame number that this access user is required within whole service time; Base station only adopts first subframe and user to transmit data, the overall transmission time T of whole link _link=Tx; The overall transmission time T of every hop link _hop=Tx; Base station assigns is constant N to access user carrier number, and the energy of every frame transmission is constant P _kt joule;

During relay transmission, the transmitted power of base station is P _bwatt, the transmitted power of relay station is P _k-P _bwatt, then R=Rr (P _b), the maximum U of repeated link efficiency U _max,

$U_{\max }=\underset{P_B}{\max }\frac{\mathrm{Rr}\left(P_B\right)\&CenterDot;T_{\mathrm{link}}}{({\mathrm{Pc}}_B+{\mathrm{Pc}}_R+P_B/{\mathrm{\&zeta;}}_B+(P_K-P_B)/{\mathrm{\&zeta;}}_R)\&CenterDot;T_{\mathrm{hop}}},s.t.\mathrm{Sr}\left(P_B\right)\&GreaterEqual;r$

Wherein Rr (P _b) for base-station transmitting-power be P _btime the total speed of repeated link, r is the minimum signal to noise ratio requirement of current access user, Sr (P _b) for base-station transmitting-power be P _btime obtainable repeated link signal to noise ratio;

When base station is directly transmitted, the transmitted power of base station is P _b=P _k, then P _k-P _b=0, Pc _r=0, R=Rd (P _k); The efficiency U of link of direct transferring is U _d,

$U_d=\frac{\mathrm{Rd}\left(P_K\right)\&CenterDot;T_{\mathrm{link}}}{({\mathrm{Pc}}_B+P_K/{\mathrm{\&zeta;}}_B)\&CenterDot;T_{\mathrm{hop}}},s.t.\mathrm{Sd}\left(P_K\right)\&GreaterEqual;r$

Wherein Rd (P _k) for base-station transmitting-power be P _ktime the total speed of the link that direct transfers, Sd (P _k) for base-station transmitting-power be P _ktime the obtainable link signal to noise ratio that direct transfers;

Compare the efficiency U of the link that direct transfers _dwith the efficiency maximum U of each repeated link _max, the link selecting maximum numerical value corresponding transmits.