CN104202075A - Wireless data transmission method based on multiple-input and multiple-output fast multiuser scheduling - Google Patents

Abstract

The invention relates to a wireless data transmission method based on multiple-input and multiple-output fast multiuser scheduling. The method includes the steps: 1, a mobile station receives a public pilot frequency sequence transmitted by a base station, processes the public pilot frequency sequence to obtain precise channel status information and feeds back the information to the base station; 2, all K mobile station users are randomly divided into M groups, each including N users; 3, in the M groups, all possible combinations of k users in simultaneous communication are selected from each N users by the method of exhaustion, sum capacity of a system is calculated according to vector of the received signal of each usher, and one group having the maximum sum capacity is selected; 4, in the M groups, the group having the maximum sum capacity is selected for communication with the base station; 5, a base station transmitter processes each user signal in the selected user combination, and the user signals are sent out through an antenna; 6, each user receiver in the selected user combination receives signals by means of maximal-ratio combining. The wireless data transmission method has the advantages such that required calculation is lessened, and efficiency is improved.

Description

A kind of based on many inputs-export radio data transmission method of multi-user's fast dispatch more

Technical field

The present invention relates to a kind ofly based on many inputs-export the radio data transmission method of multi-user's fast dispatch more, belong to wireless communication technology field.

Background technology

The mimo system of many antennas that separate in the two ends of wireless communication link usage space, can in point-to-point communication, obtain space diversity gain to improve the reliability of transmission, or acquisition space division multiplexing gains to improve spectrum efficiency.Be embodied in: (1) space diversity is mainly used in anti-multipath fading, for a mimo system with N root reception antenna and M transmit antennas, suppose different antennae between channel obey independent identically distributed Rayleigh decline, application Space Time Coding can obtain the order of diversity of NM.Even if therefore, under very complicated communication environments, mimo system also can be realized the high-quality transmission of data flow.(2) space division multiplexing is mainly used in improving transmission rate, under the assumed condition of independent channel the capacity of mimo system with min{N, M} linear growth.In addition the virtual MIMO technology consisting of multiple radio nodes, also can be widely used in the environment such as wireless sensor network and Mesh network.

The above outstanding advantages of MIMO technology becomes the inevitable direction of Development of Wireless Communications, it is the key technology of high-speed mobile net of new generation, fixed broadband wireless access (BWA) net, what become IEEE 802.16 (WiMAX) and IEEE 802.11n can selecting technology, is the research direction that new generation of wireless communication system (4G, 5G) gains great popularity.

MIMO multi-user diversity technology is considered the feature of data service, adopts efficient user's scheduling mechanism, can increase substantially the spectrum efficiency of Access Network under high density user condition.Although mimo system can improve by increasing antenna number the capacity of system under the situation of alone family, but increase antenna, the cost, the power consumption etc. that make system are significantly risen.In addition, actual communication system, the multi-user system being normally made up of many users, needs to consider how to reduce interference between user, how reasonably between user, to distribute limited Radio Resource.

In the point-to-multipoint data link being formed by AP (or base station) and multiple mobile subscriber, due to the stochastic volatility of wireless channel, they are separate to the decline in time of the channel of base station, consider that data service is to the insensitive feature of limited time delay, insert a packet scheduler at medium key-course, at each time slot according to each user to the channel condition information between AP (CSI), adopt suitable scheduling strategy shared allocation of radio resources to channel quality best one or one group of user, can increase substantially the throughput of MIMO multi-user system, thereby obtain multi-subscriber dispatching gain---multi-user diversity gain (MUD).In addition, by designing suitable system configuration, introducing the measures such as transmitting terminal preliminary treatment, can increase artificially amplitude and the rate of change of channel fading, further improve multi-user diversity gain.

In sum, in access net system, adopt the MIMO multi-user diversity technology can be in the case of not increasing the input of antenna and related hardware, increase substantially the throughput of system under multi-user's condition, have without extra transmitting power, without taking too much bandwidth resources, strong adaptability to various transmission technologys and using the advantages such as flexible, can be directly used in the 3G standard such as WIMAX, TD-SCDMA and LTE evolution version thereof, become the study hotspot of new generation of wireless communication system.

In order to obtain multi-user diversity gain, need to participate in transmission the suitable user of each Slot selection (scheduling).Current dispatching algorithm is mainly divided into the scheduling of alone family and multi-subscriber dispatching.

(1) alone family scheduling, only dispatches a user at each time slot and participates in transmission.Related scheduling algorithm mainly contains following several:

1. greedy dispatching method, participates in transmission the best user of each Slot selection channel condition.The user that this algorithm is selected has the signal to noise ratio of optimum reception conventionally, can obtain the highest throughput of system.But the chance that those users far away apart from base station may not access all the time, therefore the method is not considered user's fairness.

2. proportional fair dispatching method, participates in transmission the user of the ratio maximum of each Slot selection instantaneous signal-to-noise ratio and average signal-to-noise ratio.The user that this algorithm is selected is conventionally in oneself best channel condition (not considering to compare with other user) for a period of time, and therefore the method fully takes into account the impact of user present position on access, can obtain best user fairness.But throughput of system declines to some extent.

(2) multi-subscriber dispatching participates in transmission the multiple users of each timeslot scheduling simultaneously.Relevant dispatching method is mainly exhaustive search algorithm.Be provided with K user and wish access, system support is transmitted for n user simultaneously simultaneously, and exhaustive search algorithm need to travel through all plant combination.In the time that the number of users k that participates in the number of users K of scheduling and choose increases, the amount of calculation of system call can increase considerably (the K into Ο ^k), make on the one hand overhead too high and cannot bear, causing on the other hand processing time delay increases, to such an extent as to schedule speed cannot be caught up with the variation of channel, and then reduce the multi-user diversity gain obtaining the scheduling that may lead to errors.

Visible, the exhaustive search dispatching algorithm adopting based on existing MIMO multi-user diversity technology is carried out multi-user data transmission, faces complexity and increases too fast problem with participating in dispatched users number.

Summary of the invention

The object of the invention is to make up above-mentioned technological deficiency, reduce dispatching algorithm complexity, a kind of radio data transmission method based on many inputs-many output (MIMO) multi-user fast dispatch is provided, is applicable to MIMO, virtual MIMO and adopts the RFDC environment such as mobile radio communication, MESH network, wireless sensor network of correlation technique.

Object of the present invention is achieved by the following technical programs:

Based on many inputs-export a radio data transmission method for multi-user's fast dispatch, the method comprises the following steps more:

(1) travelling carriage receiving terminal receives the common pilot sequence of being launched by base station, the accurate channel condition information of treated acquisition, then by described information feedback to base station;

(2) base station is according to described channel condition information to requiring K the user who participates in transmission to be divided at random M group, and every group of number of users is N;

(3) in M group, adopt respectively the method for exhaustion from choose all possible combination that k user communicates by letter N user separately simultaneously, calculate system and the capacity under various combinations according to each user's reception signal phasor, select one group of k user of system and capacity maximum;

(4) relatively M organizes one group of k user's of the system chosen separately and capacity maximum system and capacity, chooses k the user of a group of system and capacity maximum in M group and participates in the communication between base station;

(5) base station transmitter carries out respectively chnnel coding, power control and beam forming processing to selecting each subscriber signal in system and capacity maximum in M group one group, goes out by antenna transmission;

(6) in M group, in one group of system and capacity maximum, each receiver user adopts high specific merging mode to receive signal.

Further, in step (3), receiving signal phasor calculates according to following formula:

$r=\sqrt{P_0}{H}_0{w}_T{s}_0+\underset{j=1}{\overset{L}{\mathrm{\Σ}}}\sqrt{P_j}{H}_j{s}_j+n$

Wherein, r is N _r× 1 receives signal phasor, s ₀for transmitting, P ₀for targeted customer's mean receiving power, P _jfor the average power of interference user j and suppose that the power of each interference user is identical, H ₀for N _r× N _tdimension channel matrix, H _jfor N _r× N _tdimension interference channel matrix, n is white complex gaussian noise vector, L is interference user number, w _tfor transmit beam-forming vector, Sj is the signal of interference user transmitting.

Further, common-channel interference each other between the user who simultaneously communicates in step (3), the Signal Interference and Noise Ratio of each mobile subscriber's receiving terminal when monkey chatter is:

$\mathrm{\γ}=\frac{{\mathrm{\Ω}}_0{\mathrm{\λ}}_{\max }}{\frac{{\mathrm{\Ω}}_I\underset{j=1}{\overset{L}{\mathrm{\Σ}}}{\left|\right|u_{\max }^H{H}_0^H{H}_j\left|\right|}^2}{{\mathrm{\λ}}_{\max }}+1}$

Wherein λ _maxfor eigenvalue of maximum, u _maxbe eigenvalue of maximum λ _maxcharacteristic of correspondence vector, H is that conjugation turns order operator, Ω ₀for user's signal noise ratio, Ω _ifor the signal to noise ratio of interference user, H ₀for N _r× N _tdimension channel matrix, H _jfor N _r× N _tdimension interference channel matrix.

Further, system and capacity adopt following formula to determine:

For C=log ₂(1+ γ);

Wherein C is power system capacity, and γ is the Signal Interference and Noise Ratio SINR of each mobile subscriber's receiving terminal.

Further, complete related operation by the applicable parallel algorithm of dividing into groups.

Compared with prior art, advantage of the present invention is as follows:

1, the grouping multi-user fast dispatch method of MIMO multi-user diversity system of the present invention, in the situation that system capacity loss is limited, its scheduling complexity is by the Ο (K of traditional exhaustive search algorithm ^k) greatly drop to M Ο (N ^k), K=MN.

2, the grouping multi-user fast dispatch method of MIMO multi-user diversity system of the present invention, the user that being particularly suitable for adopting parallel computation to complete dispatching office needs selects, and can further improve system operation efficiency.

Generally speaking, the new dispatching method that the present invention proposes can reach compromise preferably between throughput of system and scheduling complexity, therefore has higher practical value.

Brief description of the drawings

Fig. 1 is the multiuser MIMO-MRC system base-station transmitter system block diagram that adopts grouping multi-user fast dispatch method;

Fig. 2 is the overall scheduling algorithm block diagram in the multi-user MIMO system of the embodiment of the present invention;

Fig. 3 selects in the group in the multi-user MIMO system of the embodiment of the present invention and k user's of capacity maximum algorithm block diagram

Fig. 4 is the power system capacity that obtains under 2 × 2MIMO-MRC system algorithm different grouping of the present invention and the comparison of traditional method of exhaustion;

Fig. 5 is the scheduling complexity of correspondence under 2 × 2MIMO-MRC system algorithm different grouping of the present invention and the comparison of traditional method of exhaustion.

Embodiment

As shown in Figure 1 to Figure 3, consider the down link of the multi-user MIMO system being formed by a base station and K mobile subscriber, settle respectively N in base station and travelling carriage _tand N _rroot antenna, has L Ge Gong road interference user in channel, interference user is installed N _rroot antenna.Thus, each travelling carriage or jamming station and base station form a N _t× N _rdimension MIMO multiaerial system.Adopt beam forming at base station transmitter end, travelling carriage receiving terminal adopts high specific to merge and receives, and forms MIMO-MRC system.

At each time slot, scheduling step is as follows:

(1) K travelling carriage receiving terminal can be by receiving the common pilot sequence of being launched by base station, the accurate channel condition information of treated acquisition (CSI), and by feedback channel without postponing, undistorted CSI is fed back to base station transmitter, the delay of feedback channel and error are ignored.

(2) base station is according to described channel condition information to requiring K the user who participates in transmission to be divided at random M group, and every group of number of users is N;

(3) in M group, adopt respectively the method for exhaustion from choose all possible combination that k user communicates by letter N user separately simultaneously, receiving signal phasor according to each user calculates system under various combinations and capacity and (refers to capacity the capacity that two and above user communicate simultaneously, because these users disturb each other, therefore when capacity is conventionally less than each user and communicates by letter separately capacity and), select k user of that group of system and capacity maximum.Although it should be noted that at transmission end of base station and configured beam forming vector matrix for each travelling carriage, common-channel interference each other still between pairing user;

(4) relatively M organizes one group of k user's of the system chosen separately and capacity maximum system and capacity, and k user of that group of selecting system and capacity maximum participates in the communication between base station, and other users are in silence;

(5) base station transmitter carries out respectively chnnel coding, power control and beam forming processing to selecting each subscriber signal in system and capacity maximum in M group one group, passes through N _troot antenna transmission is gone out.These signals will be sneaked into additive white Gaussian noise in transmitting procedure;

(6) in M group, in one group of system and capacity maximum, each receiver user adopts high specific merging mode to receive signal.

After a time slot finishes, repeating step (1)-(6).

As shown in Figure 4, compared with the exhaustive dispatching algorithm of tradition, the system that the inventive method is corresponding and capacity have certain loss, and along with the increase loss of packet count progressively improves, show that packet count is unsuitable excessive;

As shown in Figure 5, count K and choose number of users k to become Ο (K with participating in dispatched users with traditional scheduler algorithm complex ^k) relation increases and compare, the scheduling complexity of new dispatching algorithm drops to M Ο (N greatly ^k), N=K/M.It should be noted that especially corresponding dispatching algorithm is specially adapted to parallel computation, contributes to further to improve schedule speed and efficiency owing to adopting packet mode.

Show the new dispatching method that body of the present invention is thick, provide a kind of effective method for reach good balance between power system capacity and scheduling complexity, improved the system realizability of related algorithm, there is higher practical value.

Claims (5)

1. based on many inputs-export a radio data transmission method for multi-user's fast dispatch, it is characterized in that, the method comprises the following steps more:

(1) travelling carriage receiving terminal receives the common pilot sequence of being launched by base station, the accurate channel condition information of treated acquisition, then by described information feedback to base station;

(2) base station is according to described channel condition information to requiring K the user who participates in transmission to be divided at random M group, and every group of number of users is N;

(3) in M group, adopt respectively the method for exhaustion from choose all possible combination that k user communicates by letter N user separately simultaneously, calculate system and the capacity under various combinations according to each user's reception signal phasor, select one group of k user of system and capacity maximum;

(4) relatively M organizes one group of k user's of the system chosen separately and capacity maximum system and capacity, chooses k the user of a group of system and capacity maximum in M group and participates in the communication between base station;

(5) base station transmitter carries out respectively chnnel coding, power control and beam forming processing to selecting each subscriber signal in system and capacity maximum in M group one group, goes out by antenna transmission;

(6) in M group, in one group of system and capacity maximum, each receiver user adopts high specific merging mode to receive signal.

2. method according to claim 1, is characterized in that, receives signal phasor and calculate according to following formula in step (3):

$r=\sqrt{P_0}{H}_0{w}_T{s}_0+\underset{j=1}{\overset{L}{\mathrm{\Σ}}}\sqrt{P_j}{H}_j{s}_j+n$

Wherein, r is N _r× 1 receives signal phasor, s ₀for transmitting, P ₀for targeted customer's mean receiving power, P _jfor the average power of interference user j and suppose that the power of each interference user is identical, H ₀for N _r× N _tdimension channel matrix, H _jfor N _r× N _tdimension interference channel matrix, n is white complex gaussian noise vector, L is interference user number, w _tfor transmit beam-forming vector, Sj is the signal of interference user transmitting.

3. method according to claim 1, is characterized in that: common-channel interference each other between the user who simultaneously communicates in step (3), and the Signal Interference and Noise Ratio of each mobile subscriber's receiving terminal when monkey chatter is:

$\mathrm{\γ}=\frac{{\mathrm{\Ω}}_0{\mathrm{\λ}}_{\max }}{\frac{{\mathrm{\Ω}}_I\underset{j=1}{\overset{L}{\mathrm{\Σ}}}{\left|\right|u_{\max }^H{H}_0^H{H}_j\left|\right|}^2}{{\mathrm{\λ}}_{\max }}+1}$

Wherein λ _maxfor eigenvalue of maximum, u _maxbe eigenvalue of maximum λ _maxcharacteristic of correspondence vector, H is that conjugation turns order operator, Ω ₀for user's signal noise ratio, Ω _ifor the signal to noise ratio of interference user, H ₀for N _r× N _tdimension channel matrix, H _jfor N _r× N _tdimension interference channel matrix.

4. method according to claim 1, is characterized in that: system and capacity adopt following formula to determine:

For C=log ₂(1+ γ);

Wherein C is power system capacity, and γ is the Signal Interference and Noise Ratio SINR of each mobile subscriber's receiving terminal.

5. method according to claim 1, is characterized in that: by dividing into groups, applicable parallel algorithm completes related operation.