Summary of the invention
The invention provides the method and the device of a kind of wireless channel simulation and test, in order to the wireless channel simulation that solves the wireless communication system that can't effectively use smart antenna array in the prior art and the problem of test.
The method of wireless channel simulation provided by the invention and test comprises:
A, count the time response that L simulates every footpath respectively according to the multipath bar of wireless channel;
B, every footpath is divided into M bar road, simulates the spatial character in every footpath respectively;
C, to mergings that superpose of the signal in L bar footpath on each array element in the array element of M in the smart antenna array, obtain the radiofrequency signal that wireless channel time response and spatial character are reflected in the M road.
Preferably, described steps A comprises:
A1, count L according to the multipath bar of wireless channel input signal is L bar footpath along separate routes;
A2, respectively the L bar is directly carried out wireless channel time response simulation.
Preferably, described step B comprises:
B1, be M bar road along separate routes to every footpath in L bar footpath;
B2, respectively smart antenna array simulation is carried out on M bar road, simulated the spatial character of wireless channel.
Preferably, described step B2 comprises:
B21, simulate in the described M bar road input angle of every road respectively for each array element in the smart antenna array;
B22, obtain the amplitude control signal and the phase control signal of each array element in the smart antenna array according to described input angle;
B23, the wireless signal on M road is carried out amplitude control, M road wireless signal is carried out phase control, obtain the signal of M road reflection smart antenna array characteristic according to the phase control signal on each array element according to the amplitude control signal on each array element.
Preferably, according to the amplitude control signal on each array element the wireless signal amplitude of carrying out on M road is controlled described in the step B23, being comprised: the signal gain that on the basis of described amplitude control signal, increases each array element in the smart antenna array.
Preferably, the signal in the L bar footpath merging that superposes on each array element in M array element in the smart antenna array described in the step C comprises:
With the merging that superposes respectively of the n bar road in the M bar road corresponding on every footpath in the L bar of the wireless channel footpath, wherein, n=0,1 ... M-1.
The present invention also provides the device of a kind of wireless channel simulation and test, comprises a L port branching unit, a L time response analogue unit, a L M port branching unit, a L M unit smart antenna array analogue unit and M L port combiner unit, wherein,
Described L port branching unit is used for counting L according to the multipath bar of wireless channel input signal is the L road along separate routes, obtains the shunting sign in L bar footpath;
Described time response analogue unit is used for the time response according to described shunting sign analog wireless channel, obtains the time simulation signal;
Described M port branching unit is used for described time simulation signal is the time simulation shunting sign on M road along separate routes;
Described M unit smart antenna array analogue unit is used for the characteristic according to described M road time simulation shunting sign simulated intelligence antenna array, obtains M road spatial simulation signal;
Described L port combiner unit is used for the merging that superposes of the corresponding spatial simulation signal of described M road spatial simulation signal is obtained the radiofrequency signal of M road wireless channel.
Preferably, described time response analogue unit is channel simulator or filter.
Preferably, described L port branching unit, M port branching unit or L port combiner unit are riffle combination or coupling circuit.
Preferably, described 1 L port combiner unit and L time response analogue unit are the multi-input multi-ouput channel analogue units.
Preferably, described M unit smart antenna array analogue unit comprises: angle Input Control Element, smart antenna array analog simulation unit, M port amplitude control unit and M port phase control unit, wherein,
Described angle Input Control Element is used for the input angle in every footpath of analog wireless channel respectively;
Described smart antenna array analog simulation unit is used for simulated intelligence antenna array characteristic, and obtains the amplitude control signal and the phase control signal that are produced on each array element in the smart antenna array according to the input angle in described every footpath;
Described M port amplitude control unit is used for according to the amplitude control signal that is produced on described each array element the time simulation shunting sign amplitude of carrying out on M road being controlled, and obtains the amplitude fading signal on M road;
Described M port phase control unit is used for according to the phase control signal that is produced on described each array element M road amplitude fading signal being carried out phase control respectively, obtains the spatial simulation signal.
Preferably, described angle Input Control Element is industrial computer or computer.
Preferably, described M port amplitude control unit is continuous adjustable attenuator or controllable continuous adjustable attenuator.
Preferably, described M port phase control unit is continuous adjustable phase shifter or controllable continuous adjustable phase shifter.
Preferably, described M unit smart antenna array analogue unit further comprises: the antenna gain unit,
Described antenna gain unit is used for the signal gain of each array element of simulated intelligence antenna array;
Described M port amplitude control unit is further used for increasing described signal gain on the basis of the amplitude control signal that is produced on described each array element.
The present invention is from the basic theories of wireless channel, characteristic according to the wireless channel of the wireless communication system that has used smart antenna array, at first count L wireless channel is divided into L bar footpath, simulate the time response in every footpath in the L bar footpath more respectively according to the concrete multipath bar of wireless channel; Then, every footpath is divided into M bar road, and simulates the smart antenna characteristic of the smart antenna array of M unit, the just spatial character on M bar road according to M bar road; At last, to n (n=0,1 in the M bar road corresponding on every footpath in the L bar of the wireless channel footpath ... M-1) the bar road merging that superposes respectively obtains the radiofrequency signal of M road reflection wireless channel time response and spatial character.The present invention has not only realized the simulation to the time response of the wireless channel that uses smart antenna array, while has also been realized the simulation to the spatial character of the wireless channel that uses smart antenna array, the simulation of wireless channel of the wireless communication system that uses smart antenna array and the problem of test have well been solved, simultaneously, also for the simulation of smart antenna array with the feasible method that provides is provided.
Embodiment
The present invention at first counts L according to the concrete multipath bar of wireless channel wireless channel is divided into L bar footpath according to the characteristic of the wireless channel of the wireless communication system that has used smart antenna array, simulates the time response in every footpath in the L bar footpath more respectively; Then, every footpath is divided into M bar road, and simulates the smart antenna characteristic of the smart antenna array of M unit, the just spatial character on M bar road according to M bar road; At last, to n (n=0,1 in the M bar road corresponding on every footpath in the L bar of the wireless channel footpath ... M-1) the bar road merging that superposes respectively obtains the radiofrequency signal of M road reflection wireless channel time response and spatial character.The present invention has not only realized the simulation to the time response of the wireless channel that uses smart antenna array, also realized simultaneously simulation, well solved the simulation of wireless channel of the wireless communication system that uses smart antenna array and the problem of test the spatial character of the wireless channel that uses smart antenna array.
Below with the present invention at a base station (BS with M unit smart antenna array, Base Station) from a terminal (UE with single antenna, User Equipment) process of received signal is an example, is explained in detail to the main realization principle of technical solution of the present invention, embodiment and to the beneficial effect that should be able to reach in conjunction with each accompanying drawing.
At first, the multipath number that setting BS receives wireless channel power time delay envelope is L, and then the smart antenna array of BS can calculate according to following formula at the signal that the received UE of time t sends:
Wherein: r (t) is a M dimensional vector, each array element in the smart antenna array of expression M unit, is that each single antenna is in the received radiofrequency signal of time t;
X (t-τ
i) be directly to introduce time delay τ at the i bar
iThe wireless signal that UE launched;
N (t) is the additive noise vector, is a M dimensional vector;
Especially, h
i(t) be that the i bar of expression from UE to BS be the composite phase and the amplitude of time delay directly, is a M dimensional vector equally at the space channel coefficient in the i bar footpath of time t.h
i(t) computing formula is as follows in wireless communication system:
Wherein, β
i(t) be the rapid fading coefficient, be one with UE movement speed v, signal(-) carrier frequency f
c, the signal sampling frequency f
sRelevant coefficient all is set at independently rapid fading for every footpath;
γ
i(t) be the slow fading coefficient, be one with UE movement speed v, signal sampling frequency f
sRelevant coefficient;
P
iBe the power tap in i bar footpath, also different according to the different values of channel circumstance;
δ (t-τ
i) be the time delay of i bar footpath power tap, τ
iWith P
iCorresponding;
φ
iBe the phase deviation in i bar footpath;
θ
iIt is the arrival direction angle in i bar footpath;
F (θ
i) be the factor of single antenna characteristic in the expression smart antenna array, relevant with array element type in the smart antenna array, be a M dimensional vector, for different array element types, f (θ
i) expression formula is also different;
A (θ
i) be a smart antenna array response vector, be a M dimensional vector, relevant with the array type of smart antenna array, to different array type, a (θ
i) expression formula is also different.
Especially, the array element type is meant the pattern characteristics of single antenna in the smart antenna array, if directional diagram is an omnidirectional, is called omnidirectional antenna, if directional diagram is to point to some directions, then is called directional antenna.Array type is the antenna array structure of the smart antenna array of M root antenna element composition, and is as annular, linear etc.
h
i(t)
Part reflects the time response of wireless channel, comprise delay, Doppler effect, rapid fading etc.; h
i(t) f (θ in
i) a (θ
i) part reflects the spatial character of wireless channel, as the spatial character of single antenna in multipath signal arrival direction, aerial array geometry, angle spread and the smart antenna array etc.
L described here is the multipath number of wireless channel, and (3GPP, the 3 in International Telecommunications Union (ITU, InternationalTelecommunication Union) and 3G (Third Generation) Moblie cooperative association
RdGeneration Partnership Project) stipulated in the relevant criterion that the multipath bar of respective channel type counts the power tap P in L, every footpath
iTime delay τ with corresponding i bar footpath power tap
iDeng the wireless channel parameter.
In the scheme provided by the invention, count the time response that L simulates every footpath in the L bar footpath respectively, i.e. h according to the concrete multipath bar of wireless channel
i(t)
Part; On the M in every footpath bar road, simulate the smart antenna characteristic of the smart antenna array of M unit, obtain the spatial character of wireless channel, i.e. h
i(t) f (θ in
i) a (θ
i) part.
Above-mentioned characteristic according to wireless channel, the invention provides the device of a kind of wireless channel simulation and test, as shown in Figure 2, this device comprises a L port branching unit, a L time response analogue unit, a L M port branching unit, a L M unit smart antenna array analogue unit and M L port combiner unit.Wherein,
L port branching unit is used for counting L according to the concrete multipath bar of wireless channel input signal is divided into the L road, and respectively to L time response analogue unit output L bar shunting sign directly.
Especially, the implementation of L port branching unit has multiple, for example, adopts riffle to combine or adopt the coupling circuit form.
The time response analogue unit is used for the time response according to the shunting sign analog wireless channel that receives, and to M port branching unit output time analog signal.
The time response analogue unit is used for the time response in every footpath in the analog wireless channel, i.e. h
i(t)
Part realizes with channel simulator or filter usually.Can in the time response analogue unit, set the parameter relevant respectively with the wireless channel time response:
With the rapid fading factor beta
i(t) Xiang Guan parameter: speed v, carrier frequency f
c, sampling frequency f
s
With the slow fading coefficient gamma
i(t) Xiang Guan parameter: speed v, sampling frequency f
s
The power tap P in i bar footpath
i
With P
iCorresponding τ
i
The phase deviation φ in i bar footpath
i
Especially, 1 L port combiner unit and L time response analogue unit also can pass through corresponding multiple-input and multiple-output (MIMO, Multi-Input Multi-Output) channel simulator and realize.When using the mimo channel simulator to realize the time simulation in L bar footpath, need use single input multi-output mode of mimo channel simulator, and set the wireless channel time response relevant parameter in every footpath respectively.
M port branching unit, the time simulation signal that is used for receiving is the time simulation shunting sign on M road along separate routes, and exports to M unit smart antenna array analogue unit.
Especially, the implementation of M port branching unit has multiple, for example, adopts riffle to combine or adopt the coupling circuit form.
M unit smart antenna array analogue unit, the characteristic that is used for difference simulated intelligence antenna array on the M road time simulation shunting sign that receives, promptly smart antenna array is carried out modeling and simulating, simulated intelligence antenna array characteristic, according to the input angle of every shunting sign for each array element in the smart antenna array, obtain amplitude control signal and phase control signal on each array element in the smart antenna array, according to amplitude control signal on each array element in the smart antenna array and phase control signal the M road time simulation shunting sign that receives is decayed and phase shifting control, make the spatial character of M road time simulation shunting sign reflection wireless channel, i.e. h
i(t) f (θ in
i) a (θ
i) part, and respectively to M L port combiner unit output region analog signal, the output rule is: each M unit smart antenna array analogue unit is respectively with i (i=0,1 in the M road spatial simulation signal that obtains ... M-1) spatial simulation signal in road exports i L port combiner unit to.
The merging that superposes of L port combiner unit, the spatial simulation signal that is used for receiving respectively, the radiofrequency signal of output M road wireless channel.
Especially, the implementation of L port combiner unit has multiple, for example, adopts riffle to combine or adopt the coupling circuit form.
Especially, among the embodiment of device provided by the invention, the concrete composition structure of described M unit smart antenna array analogue unit comprises angle Input Control Element, smart antenna array analog simulation unit, M port amplitude control unit and M port phase control unit as shown in Figure 3.Wherein,
The angle Input Control Element is used to simulate the input angle θ in every footpath
i, and export to smart antenna array analog simulation unit.
Especially, the angle Input Control Element has multiple implementation method, for example industrial computer or computer.
Smart antenna array analog simulation unit is used for smart antenna array is carried out modeling and simulating, and simulated intelligence antenna array characteristic is according to the input angle θ in every the footpath that receives
iSimulation h
i(t) f (θ of the spatial character of reflection wireless channel in
i) a (θ
i) part, provide that each array element is θ for each arrival direction in the smart antenna array
iIncoming wave the amplitude control signal and the phase control signal that on each array element, are produced; Export the amplitude control signal that is produced on each array element to M port amplitude control unit respectively, export the phase control signal that is produced on each array element to M port phase control unit.
Especially, amplitude control signal and the phase control signal that is produced on each array element adopts following computational methods:
Amplitude control signal=abs (f (θ
i) a (θ
i))
Phase control signal=angle (f (θ
i) a (θ
i))
Wherein,
F (θ
i) be the factor of array element characteristic in the expression smart antenna array, relevant with array element type in the smart antenna array, be a M dimensional vector, for different array element types, f (θ
i) expression formula is also different.
Parameter f (the θ of expression array element spatial character
i) can obtain from the directional diagram of each array element smart antenna array that measures, also can obtain by the directional diagram of each array element in smart antenna array of emulation in theory.Spacing is the even linear fan section intelligent antenna battle arrays in Unit 6 of 75mm, and each array element is to coming wave line of propagation as shown in Figure 4 in the smart antenna array that microwave dark room measures.
A (θ
i) be a smart antenna array response vector, be a M dimensional vector, relevant with the array type of smart antenna array, to different array type, a (θ
i) the expression formula difference.The M unit interval is in the even linear fan section intelligent antenna battle array of d, is θ for each incoming wave angle
iThe smart antenna array response vector be:
M port amplitude control unit is used for according to the amplitude control signal on each array element that receives the time simulation shunting sign on the M road that receives being carried out amplitude emulation decay respectively, and to the amplitude fading signal of M port phase control unit output M unit.
Especially, M port amplitude control unit has multiple implementation method, for example adopts continuous adjustable attenuator or controllable continuous adjustable attenuator.
Especially, M unit smart antenna array analogue unit further can comprise the antenna gain unit, the signal gain that is used for each array element of simulated intelligence antenna array, this signal gain is offered M port amplitude control unit, when M port amplitude control unit carries out amplitude control, on the basis of amplitude control signal, increase signal gain, better simulate the characteristic of actual smart antenna array.Can there be multiple implementation the antenna gain unit, uses amplifier to realize the simulation of antenna gain usually.
M port phase control unit is used for according to the phase control signal on each array element that receives the M element amplitude deamplification that receives being carried out phase control respectively, the spatial simulation signal on output M road.
Especially, M port phase control unit can adopt continuous adjustable phase shifter or controllable continuous adjustable phase shifter to realize.
Correspondingly, as shown in Figure 5, main realization principle process of the present invention is as follows:
Step 10, a remarkable characteristic of wireless channel has multipath effect exactly, in order accurately to simulate the characteristic of wireless channel, the characteristic in each bar footpath that the multipath effect of necessary analog wireless channel respectively produces.Can count the time response that L simulates every footpath in L bar footpath respectively according to the concrete multipath bar of wireless channel.
Especially, that the time response in every footpath simulation reflection is h
i(t)
Part, comprise delay, Doppler effect, rapid fading etc., this is a known technology of the prior art, repeats no more herein.This is normally realized by channel simulator or filter.
Step 20, every footpath in L bar footpath all is divided into M bar road, smart antenna array is carried out modeling and simulating, simulated intelligence antenna array characteristic, according to the input angle of every shunting sign for each array element in the smart antenna array, obtain amplitude control signal and phase control signal on each array element in the smart antenna array, according to amplitude control signal on each array element in the smart antenna array and phase control signal time simulation shunting sign in M road is decayed and phase shifting control, make the spatial character of M road time simulation shunting sign reflection wireless channel, i.e. h
i(t) f (θ in
i) a (θ
i) part.
Step 30 is to n (n=0,1 in the M bar road corresponding on every footpath in the L bar of the wireless channel footpath ... M-1) the bar road merging that superposes respectively obtains the radiofrequency signal of M road reflection wireless channel time response and spatial character.The radiofrequency signal of output can simulate the L bar footpath that the multipath effect of wireless channel produces and the characteristic of M unit smart antenna array more accurately, and the radiofrequency signal that promptly obtains can reflect the time response and the spatial character of wireless channel.
Especially, the present invention realizes mainly in the principle that as shown in Figure 6, the process of simulated intelligence antenna array characteristic specifically comprises in the step 20:
Step 21, simulate the input angle of every footpath respectively for each array element in the smart antenna array according to the multipath effect of wireless channel;
Step 22, smart antenna array is carried out modeling and simulating, according to the input angle of every footpath for each array element in the smart antenna array, each array element obtains amplitude control signal and phase control signal for amplitude and phase place that the input angle in every footpath of wireless channel is produced in the simulated intelligence antenna array respectively;
Step 23, the wireless signal on M road is carried out amplitude control according to the amplitude control signal on each array element, according to the phase control signal on each array element M road wireless signal is carried out phase control, finally, obtain accurately to reflect the signal of smart antenna array characteristic, that is to say that the wireless signal that obtains can reflect the spatial character of wireless channel.Can further increase the signal gain of each array element in the smart antenna array when wireless signal is carried out amplitude control, promptly on the basis of amplitude control signal, increase signal gain, better simulate the characteristic of actual smart antenna array.
Obviously, those skilled in the art can carry out various changes and modification to the present invention and not break away from the spirit and scope of the present invention.Like this, if of the present invention these are revised and modification belongs within the scope of claim of the present invention and equivalent technologies thereof, then the present invention also is intended to comprise these changes and modification interior.