CN101868022B - Cluster-based distributed antenna time frequency synchronizing method in wireless communication - Google Patents
Cluster-based distributed antenna time frequency synchronizing method in wireless communication Download PDFInfo
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Abstract
The invention relates to a cluster-based distributed antenna time frequency synchronizing method in wireless communication, and belongs to the technical field of wireless communication. The method comprises the following steps of: dividing mass distributed antennas into clusters, selecting cluster representative antennas, and performing distributed bidirectional coordinated synchronization on the cluster representative antennas; and then, initiating intra-cluster distributed bidirectional coordinated synchronization by the cluster representative antennas so as to finally realize time frequency synchronization of all distributed antennas in a system. The method has the following advantages that: through cluster division, a plurality of clusters are simultaneously synchronized, the total synchronization time is reduced and the synchronization speed is quickened; the synchronization between the cluster representative antennas is performed first and then the intra-cluster distributed bidirectional coordinated synchronization is performed so as to obtain higher synchronization precision and meet the requirement of a distributed wireless communication system for synchronization precision; and the synchronization between the distributed antennas is finished in advance so as to avoid multiple times of synchronization between a terminal user and a plurality of distributed antennas. The method reduces the system resource overhead of the terminal user, and improves the communication reliability.
Description
Technical field
The present invention relates in a kind of radio communication based on bunch distributed antenna time frequency synchronizing method, belong to wireless communication technology field.
Background technology
In the next generation wireless communication system of identical networking,, adopt the collaborative mode in spaced antenna or many base stations to transmit for the availability of frequency spectrum of further raising system with to quality of services for users more.For example; Coordinate multipoint (CoordinatedMultiple Point; Hereinafter to be referred as CoMP) transmission technology is the technology of being paid close attention to by LTE-Advanced at present, it can avoid or reduce presence of intercell interference effectively on the basis that keeps system high-frequency spectrum utilance as far as possible.The networking model that is based on BBU+RRU that the CoMP model is the most frequently used, common 1 Base Band Unit (hereinafter to be referred as BBU) connects a plurality of wireless remotes unit (hereinafter to be referred as RRU) through radio frequency optical fiber (hereinafter to be referred as RoF).RRU is similar to spaced antenna in the distributing antenna system, and the BBU through RoF and similar central processing unit is connected.
Under the scene of a plurality of spaced antenna collaboration communications, time between a plurality of spaced antennas and Frequency Synchronization provide the basic premise of reliable transmission.When a plurality of spaced antennas transmit information for one or more users simultaneously,, make user's restoring signal difficulty because the frequency of the local crystal oscillator of each spaced antenna can produce deviation in time.Thereby, guarantee that the temporal frequency of a plurality of spaced antennas is synchronous, be directly connected to user's's (like cellphone subscriber, mobile device etc.) communication quality and reliability.Synchronous motor to many spaced antennas is shaped on principal and subordinate's synchronization mechanism, opens and closes ring synchronization mechanism and two-way poll synchronization mechanism etc. at present.
In principal and subordinate's synchronization mechanism; Host node (a selected representative antennas or terminal use in many spaced antennas) sends reference signal to each from node (remaining spaced antenna); Receive after the reference signal frequency and the phase information of obtaining reference signal through phase-locked loop (PLL) from node, and then adjustment reaches synchronous purpose from the local crystal oscillator of node.But should mechanism also come with some shortcomings part:
(1) host node needs to broadcast from node to a plurality of simultaneously, than bringing more power consumption from node.When especially being host node, then need handle a large amount of next response signals since node with terminal use.
(2) owing to each need be adjusted the local crystal oscillator of oneself according to the reference signal that host node sends from node; In case the crystal oscillator deviation of host node is excessive; Occur when perhaps each is from the node processing reference signal than mistake, can cause then that main and subordinate node can't the deadline frequency synchronously.Synchronization accuracy under principal and subordinate's synchronization mechanism also can't satisfy the temporal frequency synchronisation requirement of spaced antenna cooperative system in addition.The temporal frequency synchronization accuracy that current spaced antenna/multi-base station cooperative system needs is higher than about one to two one magnitude of principal and subordinate's synchronization mechanism precision.
In two-way poll synchronization mechanism, consider a labelled spaced antenna set { C
1, C
2..., C
L, and setting antenna number, to be incremented to L from 1 be forward direction, opposite from L be decremented to 1 for the back to.Send reference signal by base station 1 to base station 2, this signal comprises the frequency and the phase information of base station 1 local crystal oscillator, and base station 2 is estimated after receiving reference signal, and adjusted local crystal oscillator according to estimated value.Send reference signal with continued to base station 3, by that analogy.Each base station is carried out the estimation of time and frequency through the mode of two-way poll.Then,, calculate time and frequency values that the local crystal oscillator of each base station need be adjusted, finally reach the purpose of a plurality of base stations time, Frequency Synchronization through the symmetry of front and back bi-directional estimation.Two-way poll synchronization mechanism can be met time, the Frequency Synchronization precision of spaced antenna/multi-base station cooperative system requirements, but also there is weak point in this synchronization mechanism:
Frequency and phase estimation are carried out according to receiving reference signal in each base station; And continue to send reference signal and all need independently time slot for the process of next base station; Have L spaced antenna cooperative multicast system for one; Along with the increase of spaced antenna number L, the synchronously required resource overhead of whole system can linearly increase.In DWCS/multi-base station cooperative communication system, general spaced antenna number L under a central controller controls is bigger, and synchronizing process need periodically be carried out.Though two-way poll synchronization mechanism can access the higher synchronous precision, lock in time, expense was excessive.
In a word; Present existing synchronization mechanism has problems aspect system resource overhead, lock in time and synchronization accuracy, can not realize high efficiency, high precision time Frequency Synchronization to a plurality of spaced antennas in DWCS/multi-base station cooperative communication system.
Summary of the invention
The objective of the invention is to propose in a kind of radio communication based on bunch distributed antenna time frequency synchronizing method; At first; The communication system that a plurality of spaced antennas are arranged is carried out sub-clustering handle, select a bunch representative antennas, accomplish the high-precise synchronization between bunch representative antennas.Then, the temporal frequency of being initiated a plurality of spaced antennas in each bunch by bunch representative antennas is synchronous, and the temporal frequency of all spaced antennas is synchronous in the finally realization system.
In the radio communication that the present invention proposes based on bunch distributed antenna time frequency synchronizing method, may further comprise the steps:
(1) spaced antenna of the M=PN in the wireless communication system is divided into P bunch, p=1,2; ..., P, the spaced antenna number in each bunch are N; N=1,2 ...; N; The expression of n spaced antenna in p bunch with
, then the spaced antenna set is
p=1 in every bunch, 2; ..., P;
Setting up departments, the unified reference clock signal of spaced antenna is ψ (t)=exp{j (Ω t+ Φ) in the system }, wherein Ω is the frequency of local crystal oscillator, and t is the unified overall reference time, and Φ is the phase place of local crystal oscillator.Owing to there is the deviation of local crystal oscillator, thus in the system any spaced antenna i local crystal oscillator signal indication be:
ψ
i(t)=exp{j(Ω
it+Φ
i+n
i(t))},i=1,2,...,M-1,M (1)
Ω in the following formula
iBe local crystal oscillator frequency, Φ
iThe phase place of representing local crystal oscillator, n
i(t) be the noise jamming of local crystal oscillator;
According to above-mentioned (1) formula, obtain that the current local zone time of any spaced antenna i is in the said system:
t
i=(Ω
it+Φ
i+n
i(t))/Ω=α
i(t+Δ
i(t)),i=1,2,...,M-1,M (2)
α wherein
i=Ω
i/ Ω, the ratio of the local crystal oscillator frequency of any spaced antenna i and unified overall crystal oscillator frequency in the expression system; Δ
i(t)=(Φ
i+ n
i(t))/Ω
i, the local zone time deviation of any spaced antenna i in the expression system considers that the local clock deviation is a fixed value in a unit propagates time slot, then the local zone time t of any spaced antenna i in the system
iWith the overall situation reference time t relational expression be t
i=t+ Δ
i
(2) from N the spaced antenna of above-mentioned each bunch, choose 2 spaced antennas
and
as bunch representative antennas, then adjacent P bunch produces 2P bunch representative antennas;
(3) above-mentioned all bunch representative antennas are carried out the distributed bidirectional cooperation synchronously, detailed process is following:
(3-1) above-mentioned all bunch representative antennas are numbered the back ordering, form a bunch representative antennas set
Be abbreviated as { A
1, A
2..., A
2P-1, A
2P;
(3-2) by a bunch representative antennas A
1To a bunch representative antennas A
2Send sinusoidal signal, A by that analogy
1→ A
2→ ... → A
2P-1→ A
2P, be designated as fl transmission; After the forward direction end of transmission, by a bunch representative antennas A
2PSend identical sinusoidal signal to bunch representative antennas A
2P-1, A by that analogy
2P→ A
2P-1→ ... → A
2→ A
1, being designated as reverse transfer, fl transmission and reverse transfer take 4P-2 unit altogether and propagate time slot, wherein time slot { T
(1), T
(2)..., T
(2P-2), T
(2P-1)Be that the fl transmission time slot is gathered time slot { T
(2P), T
(2P+1)..., T
(4P-3), T
(4P-2)Be that the reverse transfer time slot is gathered;
(3-3) at above-mentioned fl transmission time slot T
(1)In, bunch representative antennas A
1The signal indication that sends is:
S
1 (1)(t)=exp{j(w
1t
1+Φ
1)} (3)
W wherein
1Be a bunch representative antennas A
1Local crystal oscillator frequency, Φ
1Phase place for local crystal oscillator;
Bunch representative antennas A
2Reception is from a bunch representative antennas A
1Signal, this signal is with bunch representative antennas A
2Local zone time t
2Be expressed as:
H wherein
1,2For from a bunch representative antennas A
1To bunch representative antennas A
2Channel Transmission gain, and it is symmetry equivalent to the channel transmitted transmission gain with the back to set fl transmission,
Be a bunch representative antennas A
2At T
(1)In the noise that receives, then bunch representative antennas A
2Estimate that the crystal oscillator frequency and the phase place that obtain are:
(3-4) repeat above-mentioned steps (3-2)-(3-3), obtain a bunch representative antennas A
iFl transmission crystal oscillator frequency and the phase place estimated be:
(3-5) reverse transfer is by a bunch representative antennas A
2PBeginning is up at reverse transfer time slot T
(4p-2)Intra-cluster representative antennas A
1Receive till the final signal;
(3-6) at above-mentioned reverse transfer time slot T
(2P)In, bunch representative antennas A
2PThe signal indication that sends is:
s
2P (2P)(t)=exp{j(w
2Pt
2P+Φ
2P)} (9)
W wherein
2PBe a bunch representative antennas A
2PLocal crystal oscillator frequency, Φ
2PPhase place for local crystal oscillator;
Bunch representative antennas A
2P-1Reception is from a bunch representative antennas A
2PSignal, this signal is with bunch representative antennas A
2P-1Local zone time t
2p-1Be expressed as:
H wherein
2P, 2P-1For from a bunch representative antennas A
2PTo bunch representative antennas A
2P-1Transmission channel gain,
Be a bunch representative antennas A
2P-1At T
(2P)In the noise that receives, then bunch representative antennas A
2P-1Estimate that the crystal oscillator frequency and the phase place that obtain are:
(3-7) repeat above-mentioned steps (3-5)-(3-6), obtain a bunch representative antennas A
iReverse transfer crystal oscillator frequency and the phase place estimated be:
(3-8) according to the fl transmission estimated result and the reverse transfer estimated result of above-mentioned each that obtains bunch representative antennas, bunch representative antennas A then
iFinal local crystal oscillator frequency and the phase place estimated are:
And obtain bunch representative antennas A based on unified overall reference time t
iLocal crystal oscillator signal be:
ψ
i(t)=exp{j((α
1w
1+α
2Pw
2P)t+λ
1+λ
2P)},i=1,2,...,2P-1,2P (17)
λ wherein
n=α
nw
nΔ
n+ Φ
n
(3-9) according to above-mentioned bunch of representative antennas A
iLocal crystal oscillator frequency and the estimated value of phase place, obtain a bunch representative antennas set
The synchronized result of local crystal oscillator signal be:
(4) according to the synchronized result of bunch representative antennas between above-mentioned each bunch, then, the distributed bidirectional cooperation between a plurality of spaced antennas in being initiated bunch by bunch representative antennas of each bunch synchronously; The same in default wherein and method for synchronous and the above-mentioned steps (3) is example with p bunch N spaced antenna, p=1; 2; ..., P, concrete steps are following:
(4-1) after accomplishing bunch representative antennas set synchronously, to bunch in N spaced antenna number the back ordering, form spaced antenna and gather
Be abbreviated as { B
1, B
2..., B
N, spaced antenna wherein
Be two bunches of representative antennas of this bunch;
(4-2) by bunch in spaced antenna B
1To spaced antenna B
2Send sinusoidal signal, B by that analogy
1→ B
2→ ... → B
N-1→ B
N, be designated as fl transmission; After the forward direction end of transmission, by spaced antenna B
NSend identical sinusoidal signal to spaced antenna B
N-1, B by that analogy
N→ B
N-1→ ... → B
2→ B
1, being designated as reverse transfer, fl transmission and reverse transfer take 2N-2 unit altogether and propagate time slot, wherein time slot
Be the set of fl transmission time slot, time slot
Be the set of reverse transfer time slot;
(4-3) at above-mentioned fl transmission time slot
In, spaced antenna B
1The signal indication that sends is:
x
1 (1)(t)=exp{j(w
1t
1+Φ
1)} (19)
W wherein
1Be spaced antenna B
1Local crystal oscillator frequency, Φ
1Phase place for local crystal oscillator;
Then, spaced antenna B
2Reception is from spaced antenna B
1Signal, this signal is used spaced antenna B
2Local zone time t
2Be expressed as:
H wherein
1,2For from spaced antenna B
1To spaced antenna B
2Channel Transmission gain, and it is symmetry equivalent to the channel transmitted transmission gain with the back to set fl transmission,
Be spaced antenna B
2 In the noise that receives, then spaced antenna B
2Estimate that the crystal oscillator frequency and the phase place that obtain are:
(4-4) repeat above-mentioned steps (4-2)-(4-3), spaced antenna B in the spaced antenna set in obtaining bunch
iFl transmission crystal oscillator frequency and the phase place estimated be:
(4-5) reverse transfer is by spaced antenna B
NInitiate, up to time slot
Middle spaced antenna B
1Receive till the final signal;
(4-6) at above-mentioned reverse transfer time slot
In, spaced antenna B
NThe signal indication that sends is:
x
N (N)(t)=exp{j(w
Nt
N+Φ
N)} (25)
W wherein
NBe spaced antenna B
NLocal crystal oscillator frequency, Φ
NPhase place for local crystal oscillator;
Then, spaced antenna B
N-1Reception is from spaced antenna B
NSignal, this signal is used spaced antenna B
N-1Local zone time t
N-1Be expressed as:
H wherein
N, N-1For from spaced antenna B
NTo spaced antenna B
N-1Transmission channel gain,
Be spaced antenna B
N-1 In the noise that receives, then spaced antenna B
N-1Estimate that the frequency and the phase place that obtain are
(4-7) repeat above-mentioned steps (4-5)-(4-6), spaced antenna B in the spaced antenna set in obtaining bunch
iReverse transfer crystal oscillator frequency and the phase place estimated be:
(4-8) according to above-mentioned obtain bunch in the fl transmission estimated result and the reverse transfer estimated result of spaced antenna, then spaced antenna B
iFinal local crystal oscillator frequency and the phase place estimated are:
And obtain spaced antenna B based on unified overall reference time t
iLocal crystal oscillator signal be:
ψ
i(t)=exp{j((α
1w
1+α
Nw
N)t+λ
1+λ
N)},i=1,2,...,N-1,N (33)
λ wherein
n=α
nw
nΔ
n+ Φ
n
(4-9) according to spaced antenna B in above-mentioned bunch
iLocal crystal oscillator frequency and the estimated value of phase place, obtain p bunch bunch in the spaced antenna set
The synchronized result of local crystal oscillator signal be:
(4-10) owing to p bunch bunch representative antennas
and bunch representative antennas
are accomplished the synchronous of local crystal oscillator with bunch representative antennas of other bunches in above-mentioned (3) step, so the P in the whole system bunch is total to M spaced antenna deadline Frequency Synchronization.Be about to obtain in above-mentioned formula (18) the substitution formula (34) that the final synchronized result of all spaced antennas is in the whole system:
In the radio communication that the present invention proposes based on bunch distributed antenna time frequency synchronizing method, its advantage is:
1, time frequency synchronizing method of the present invention through with the sub-district sub-clustering, makes a plurality of bunches to carry out simultaneously under the prerequisite that guarantees higher synchronization accuracy, having reduced total lock in time synchronously, has accelerated synchronizing speed.
If total M=PN of the spaced antenna number in the whole system, a basic transmission time slot in the synchronizing process is 1.Directly the two-way poll method for synchronous of utilization realizes that the time overhead of global synchronization is T
Tot=2M-2 is along with the linear growth trend of spaced antenna number M in the whole system.And utilization institute of the present invention extracting method expense lock in time be
promptly when each bunch of choose reasonable the spaced antenna number is
time, required lock in time, expense was only with the linear growth trend of square root of the spaced antenna number M in the whole system.
2, time frequency synchronizing method of the present invention; It is synchronous earlier bunch representative antennas of each bunch to be carried out temporal frequency; And then the cooperation of the distributed bidirectional in carrying out bunch can obtain higher synchronous accuracy synchronously, can satisfy the requirement of DWCS/wireless communication systems such as multi-base station cooperative wireless communication system to synchronization accuracy.
3, time frequency synchronizing method of the present invention; Utilization based on bunch distributed antenna time frequency synchronizing method; Can make a plurality of spaced antennas with before terminal use's (like cellphone subscriber, mobile device etc.) communicates by letter, the temporal frequency of accomplishing in advance between the spaced antenna is synchronous, avoids the terminal use to carry out repeatedly synchronous with a plurality of spaced antennas respectively; And only need to accomplish synchronously with a spaced antenna, just can reach synchronous with the temporal frequency of the spaced antenna of all participation collaboration communications.Reduce terminal use's system resource overhead, improved the reliability of communication.
Description of drawings
Fig. 1 is the FB(flow block) of the inventive method.
Fig. 2 is a bunch division model sketch map in one embodiment of the present of invention.
Fig. 3 is the distributed bidirectional of bunch representative antennas set among Fig. 2 synchronous sketch map of cooperating.
Embodiment
Below in conjunction with Fig. 1 introduce in the radio communication that the present invention proposes based on bunch an embodiment of distributed antenna time frequency synchronizing method.The present invention sends out among the embodiment, and the central controller of wireless communication system connects 21 spaced antennas, and concrete steps are following:
(1) M=21 spaced antenna is divided into bunch, bunch uses the p mark, total P=3 bunch, spaced antenna is used the n mark in bunch, and N=7 spaced antenna arranged in each bunch.The expression of n antenna in p bunch with
; Then the set of the spaced antenna of each bunch is
p=1; 2; 3; Fig. 2 has provided a model instance of bunch division, and wherein spaced antenna 1 is a bunch representative antennas with spaced antenna 7;
(2) from 7 spaced antennas of above-mentioned each bunch, choose spaced antenna
and
as bunch representative antennas, then adjacent 3 bunches produce 6 bunches of representative antennas;
(3) all bunch representative antennas are carried out the distributed bidirectional cooperation synchronously, detailed process is following:
(3-1) above-mentioned all bunch representative antennas are numbered the back ordering, form a bunch representative antennas set
Be abbreviated as { A
1, A
2, A
3, A
4, A
5, A
6, as shown in Figure 3;
(3-2) by a bunch representative antennas A
1To a bunch representative antennas A
2Send sinusoidal signal, A by that analogy
1→ A
2→ ... → A
5→ A
6, be designated as fl transmission; After the forward direction end of transmission, by a bunch representative antennas A
6Send identical sinusoidal signal to bunch representative antennas A
5, A by that analogy
6→ A
5→ ... → A
2→ A
1, being designated as reverse transfer, fl transmission and reverse transfer take 10 units altogether and propagate time slot, wherein time slot { T
(1), T
(2), T
(3), T
(4), T
(5)Be that the fl transmission time slot is gathered time slot { T
(6), T
(7), T
(8), T
(9), T
(10)Be that the reverse transfer time slot is gathered;
(3-3) at above-mentioned fl transmission time slot T
(1)In, bunch representative antennas A
1The signal indication that sends is:
s
1 (1)(t)=exp{j(w
1t
1+Φ
1)}
W wherein
1Be a bunch representative antennas A
1Local crystal oscillator frequency, Φ
1Phase place for local crystal oscillator;
Then, bunch representative antennas A
2Reception is from a bunch representative antennas A
1Signal, this signal is with bunch representative antennas A
2Local zone time t
2Be expressed as:
H wherein
1,2For from a bunch representative antennas A
1To bunch representative antennas A
2Channel Transmission gain, and it is symmetry equivalent to the channel transmitted transmission gain with the back to set fl transmission,
Be a bunch representative antennas A
2At T
(1)In the noise that receives, then bunch representative antennas A
2Estimate that the crystal oscillator frequency and the phase place that obtain are:
(3-4) repeat above-mentioned steps (3-2)-(3-3), obtain a bunch representative antennas A
iFl transmission crystal oscillator frequency and the phase place estimated be:
(3-5) reverse transfer is by a bunch representative antennas A
6Initiate, up to time slot T
(10)In bunch representative antennas A
1Receive till the final signal;
(3-6) at above-mentioned reverse transfer time slot T
(6)In, bunch representative antennas A
6The signal indication that sends is:
s
6 (6)(t)=exp{j(w
6t
6+Φ
6)} (36)
W wherein
6Be a bunch representative antennas A
6Local crystal oscillator frequency, Φ
6Phase place for local crystal oscillator;
Then, bunch representative antennas A
5Reception is from a bunch representative antennas A
6Signal, this signal is with bunch representative antennas A
5Local zone time t
5Be expressed as:
H wherein
6,5For from a bunch representative antennas A
6To bunch representative antennas A
5Transmission channel gain,
Be a bunch representative antennas A
5At T
(6)In the noise that receives, then bunch representative antennas A
5Estimate that the crystal oscillator frequency and the phase place that obtain are:
(3-7) repeat above-mentioned steps (3-5)-(3-6), obtain a bunch representative antennas A
iReverse transfer crystal oscillator frequency and the phase place estimated be:
(3-8) according to the fl transmission estimated result and the reverse transfer estimated result of above-mentioned each that obtains bunch representative antennas, bunch representative antennas A then
iFinal local crystal oscillator frequency and the phase place estimated are:
And obtain bunch representative antennas A based on unified overall reference time t
iLocal crystal oscillator signal be:
ψ
i(t)=exp{j((α
1w
1+α
6w
6)t+λ
1+λ
6)},i=1,2,3,4,5,6 (44)
λ wherein
n=α
nw
nΔ
n+ Φ
n
(3-9) according to above-mentioned bunch of representative antennas A
iLocal crystal oscillator frequency and the estimated value of phase place, obtain a bunch representative antennas set
The synchronized result of local crystal oscillator signal be:
(4) according to the synchronized result of bunch representative antennas between above-mentioned each bunch, then, the distributed bidirectional cooperation between a plurality of spaced antennas in being initiated bunch by bunch representative antennas of each bunch synchronously; 7 spaced antennas with p bunch are example, p=1,2; 3, concrete steps are following:
(4-1) after accomplishing bunch representative antennas set synchronously, to bunch in 7 spaced antennas number the back ordering, form the spaced antenna set
Be abbreviated as { B
1, B
2..., B
7, spaced antenna wherein
Be two bunches of representative antennas of this bunch;
(4-2) by bunch in spaced antenna B
1To spaced antenna B
2Send sinusoidal signal, B by that analogy
1→ B
2→ ... → B
6→ B
7, be designated as fl transmission; After the forward direction end of transmission, by spaced antenna B
7Send identical sinusoidal signal to spaced antenna B
6, B by that analogy
7→ B
6→ ... → B
2→ B
1, being designated as reverse transfer, fl transmission and reverse transfer take 12 units altogether and propagate time slot, wherein time slot
Be the set of fl transmission time slot, time slot
Be the set of reverse transfer time slot;
(4-3) at above-mentioned fl transmission time slot
In, spaced antenna B
1The signal indication that sends is:
x
1 (1)(t)=exp{j(w
1t
1+Φ
1)}
W wherein
1Be spaced antenna B
1Local crystal oscillator frequency, Φ
1Phase place for local crystal oscillator;
Spaced antenna B
2Reception is from spaced antenna B
1Signal, this signal is used spaced antenna B
2Local zone time t
2Be expressed as:
H wherein
1,2For from spaced antenna B
1To spaced antenna B
2Channel Transmission gain, and it is symmetry equivalent to the channel transmitted transmission gain with the back to set fl transmission,
Be spaced antenna B
2 In the noise that receives, then spaced antenna B
2Estimate that the crystal oscillator frequency and the phase place that obtain are:
(4-4) repeat above-mentioned steps (4-2)-(4-3), spaced antenna B in the spaced antenna set in obtaining bunch
iFl transmission crystal oscillator frequency and the phase place estimated be:
(4-5) reverse transfer is by spaced antenna B
7Initiate, up to time slot
Middle spaced antenna B
1Receive till the final signal;
(4-6) at above-mentioned reverse transfer time slot
In, spaced antenna B
2The signal indication that sends is:
x
7 (7)(t)=exp{j(w
7t
7+Φ
7)} (46)
W wherein
7Be spaced antenna B
7Local crystal oscillator frequency, Φ
7Phase place for local crystal oscillator;
Spaced antenna B
6Reception is from spaced antenna B
7Signal, this signal is used spaced antenna B
6Local zone time t
6Be expressed as:
H wherein
7,6For from spaced antenna B
7To spaced antenna B
6Transmission channel gain,
Be spaced antenna B
6 In the noise that receives, then spaced antenna B
6Estimate that the frequency and the phase place that obtain are
(4-7) repeat above-mentioned steps (4-5)-(4-6), spaced antenna B in the spaced antenna set in obtaining bunch
iReverse transfer crystal oscillator frequency and the phase place estimated be:
(4-8) according to above-mentioned obtain bunch in the fl transmission estimated result and the reverse transfer estimated result of spaced antenna, then spaced antenna B
iFinal local crystal oscillator frequency and the phase place estimated are:
And obtain spaced antenna B based on unified overall reference time t
iLocal crystal oscillator signal be:
ψ
i(t)=exp{j((α
1w
1+α
7w
7)t+λ
1+λ
7)},i=1,2,...,7 (54)
λ wherein
n=α
nw
nΔ
n+ Φ
n
(4-9) according to spaced antenna B in above-mentioned bunch
iLocal crystal oscillator frequency and the estimated value of phase place, obtain p bunch bunch in the spaced antenna set
The synchronized result of local crystal oscillator signal be:
(4-10) because p bunch bunch representative antennas
is accomplished the synchronous of local crystal oscillator with bunch representative antennas of other bunches with bunch representative antennas
in above-mentioned (3) step, so in the whole system 3 bunches totally 21 spaced antenna deadline Frequency Synchronization.Be about to obtain in above-mentioned formula (45) the substitution formula (55) that the final synchronized result of all spaced antennas is in the whole system:
Claims (1)
- In the radio communication based on bunch distributed antenna time frequency synchronizing method, it is characterized in that this method may further comprise the steps:(1) spaced antenna of the M=PN in the wireless communication system is divided into P bunch, p=1,2 ..., P, the spaced antenna number in each bunch are N, n=1, and 2 ..., N, n spaced antenna usefulness in p bunch Expression, then the spaced antenna set does in every bunchSetting up departments, the unified reference clock signal of spaced antenna is ψ (t)=exp{j (Ω t+ Φ) in the system }; Wherein Ω is the frequency of local crystal oscillator; T is the unified overall reference time; Φ is the phase place of local crystal oscillator owing to there is the deviation of local crystal oscillator, so in the system any spaced antenna i local crystal oscillator signal indication be:ψ i(t)=exp{j(Ω it+Φ i+n i(t))},i=1,2,...,M-1,M (1)Ω in the following formula iBe local crystal oscillator frequency, Φ iThe phase place of representing local crystal oscillator, n i(t) be the noise jamming of local crystal oscillator;According to above-mentioned (1) formula, obtain that the current local zone time of any spaced antenna i is in the said system:t i=(Ω it+Φ i+n i(t))/Ω=α i(t+Δ i(t)),i=1,2,...,M-1,M (2)α wherein i=Ω i/ Ω, the ratio of the local crystal oscillator frequency of any spaced antenna i and unified overall crystal oscillator frequency in the expression system; Δ i(t)=(Φ i+ n i(t))/Ω i, the local zone time deviation of any spaced antenna i in the expression system considers that the local clock deviation is a fixed value in a unit propagates time slot, then the local zone time t of any spaced antenna i in the system iWith the overall situation reference time t relational expression be t i=t+ Δ i(2) from N the spaced antenna of above-mentioned each bunch, choose 2 spaced antennas and as bunch representative antennas, then adjacent P bunch produces 2P bunch representative antennas;(3) above-mentioned all bunch representative antennas are carried out the distributed bidirectional cooperation synchronously, detailed process is following:(3-1) above-mentioned all bunch representative antennas are numbered the back ordering, form a bunch representative antennas set Be abbreviated as { A 1, A 2..., A 2P-1, A 2P;(3-2) by a bunch representative antennas A 1To a bunch representative antennas A 2Send sinusoidal signal, A by that analogy 1→ A 2→ ... → A 2P-1→ A 2P, be designated as fl transmission; After the forward direction end of transmission, by a bunch representative antennas A 2PSend identical sinusoidal signal to bunch representative antennas A 2P-1, A by that analogy 2P→ A 2P-1→ ... → A 2→ A 1, being designated as reverse transfer, fl transmission and reverse transfer take 4P-2 unit altogether and propagate time slot, wherein time slot { T (1), T (2)..., T (2P-2), T (2P-1)Be that the fl transmission time slot is gathered time slot { T (2P), T (2P+1)..., T (4P-3), T (4P-2)Be that the reverse transfer time slot is gathered;(3-3) at above-mentioned fl transmission time slot T (1)In, bunch representative antennas A 1The signal indication that sends is:s 1 (1)(t 1)=exp{j(w 1t 1+Φ 1)} (3)W wherein 1Be a bunch representative antennas A 1Local crystal oscillator frequency, Φ 1Phase place for local crystal oscillator;Bunch representative antennas A 2Reception is from a bunch representative antennas A 1Signal, this signal is with bunch representative antennas A 2Local zone time t 2Be expressed as:H wherein 1,2For from a bunch representative antennas A 1To bunch representative antennas A 2Channel Transmission gain, and it is symmetry equivalent to the channel transmitted transmission gain with the back to set fl transmission, Be a bunch representative antennas A 2At T (1)In the noise that receives, then bunch representative antennas A 2Estimate that the crystal oscillator frequency and the phase place that obtain are:(3-4) repeat above-mentioned steps (3-2)-(3-3), obtain a bunch representative antennas A iFl transmission crystal oscillator frequency and the phase place estimated be:(3-5) reverse transfer is by a bunch representative antennas A 2PBeginning is up at reverse transfer time slot T (4p-2)Intra-cluster representative antennas A 1Receive till the final signal;(3-6) at above-mentioned reverse transfer time slot T (2P)In, bunch representative antennas A 2PThe signal indication that sends is:s 2P (2P)(t 2P)=exp{j(w 2Pt 2P+Φ 2P)} (9)W wherein 2PBe a bunch representative antennas A 2PLocal crystal oscillator frequency, Φ 2PPhase place for local crystal oscillator;Bunch representative antennas A 2P-1Reception is from a bunch representative antennas A 2PSignal, this signal is with bunch representative antennas A 2P-1Local zone time t 2p-1Be expressed as:H wherein 2P, 2P-1For from a bunch representative antennas A 2PTo bunch representative antennas A 2P-1Transmission channel gain, Be a bunch representative antennas A 2P-1At T (2P)In the noise that receives, then bunch representative antennas A 2P-1Estimate that the crystal oscillator frequency and the phase place that obtain are:(3-7) repeat above-mentioned steps (3-5)-(3-6), obtain a bunch representative antennas A iReverse transfer crystal oscillator frequency and the phase place estimated be:(3-8) according to the fl transmission estimated result and the reverse transfer estimated result of above-mentioned each that obtains bunch representative antennas, bunch representative antennas A then iFinal local crystal oscillator frequency and the phase place estimated are:And obtain bunch representative antennas A based on unified overall reference time t iLocal crystal oscillator signal be:ψ i(t)=exp{j((α 1w 1+α 2Pw 2P)t+λ 1+λ 2P)},i=1,2,...,2P-1,2P (17)λ wherein n=α nw nΔ n+ Φ n(3-9) according to above-mentioned bunch of representative antennas A iLocal crystal oscillator frequency and the estimated value of phase place, obtain a bunch representative antennas set The synchronized result of local crystal oscillator signal be:(18)(4) according to the synchronized result of bunch representative antennas between above-mentioned each bunch, then, the distributed bidirectional cooperation between a plurality of spaced antennas in being initiated bunch by bunch representative antennas of each bunch synchronously; The same in default wherein and method for synchronous and the above-mentioned steps (3) is example with p bunch N spaced antenna, p=1; 2; ..., P, concrete steps are following:(4-1) after accomplishing bunch representative antennas set synchronously, to bunch in N spaced antenna number the back ordering, form spaced antenna and gather Be abbreviated as { B 1, B 2..., B N, spaced antenna wherein Be two bunches of representative antennas of this bunch;(4-2) by bunch in spaced antenna B 1To spaced antenna B 2Send sinusoidal signal, B by that analogy 1→ B 2→ ... → B N-1→ B N, be designated as fl transmission; After the forward direction end of transmission, by spaced antenna B NSend identical sinusoidal signal to spaced antenna B N-1, B by that analogy N→ B N-1→ ... → B 2→ B 1, being designated as reverse transfer, fl transmission and reverse transfer take 2N-2 unit altogether and propagate time slot, wherein time slot Be the set of fl transmission time slot, time slot Be the set of reverse transfer time slot;(4-3) at above-mentioned fl transmission time slot In, spaced antenna B 1The signal indication that sends is:x 1 (1)(t′ 1)=exp{j(w′ 1t′ 1+Φ′ 1)}(19)W ' wherein 1Be the local crystal oscillator frequency of spaced antenna B1, Φ ' 1Phase place for local crystal oscillator;Spaced antenna B 2Reception is from spaced antenna B 1Signal, this signal is used spaced antenna B 2Local zone time t ' 2Be expressed as:H ' wherein 1,2For from spaced antenna B 1To spaced antenna B 2Channel Transmission gain, and it is symmetry equivalent to the channel transmitted transmission gain with the back to set fl transmission, Be spaced antenna B 2 In the noise that receives, then spaced antenna B 2Estimate that the crystal oscillator frequency and the phase place that obtain are:Wherein With Be estimated frequency error and phase estimation error; α ' iThe ratio of the local crystal oscillator frequency of spaced antenna Bi and unified overall crystal oscillator frequency in the expression system; Δ ' iThe local zone time deviation of any spaced antenna Bi in the expression system;(4-4) repeat above-mentioned steps (4-2)-(4-3), the fl transmission of spaced antenna Bi is estimated in the spaced antenna set in obtaining bunch crystal oscillator frequency and phase place are:(4-5) reverse transfer is by spaced antenna B NInitiate, up to time slot Middle spaced antenna B 1Receive till the final signal;(4-6) at above-mentioned reverse transfer time slot In, spaced antenna B NThe signal indication that sends is:x N (N)(t′ N)=exp{j(w′ Nt′ N+Φ′ N)} (25)W ' wherein NBe spaced antenna B NLocal crystal oscillator frequency, Φ ' NPhase place for local crystal oscillator;Spaced antenna B N-1Reception is from spaced antenna B NSignal, this signal is used spaced antenna B N-1Local zone time t ' N-1Be expressed as:H ' wherein N, N-1For from spaced antenna B NTo spaced antenna B N-1Transmission channel gain, Be spaced antenna B N-1 In the noise that receives, then spaced antenna B N-1Estimate that the frequency and the phase place that obtain are(4-7) repeat above-mentioned steps (4-5)-(4-6), the reverse transfer of spaced antenna Bi is estimated in the spaced antenna set in obtaining bunch crystal oscillator frequency and phase place are:(4-8) according to above-mentioned obtain bunch in the fl transmission estimated result and the reverse transfer estimated result of spaced antenna, then spaced antenna B iFinal local crystal oscillator frequency and the phase place estimated are:And obtain spaced antenna B based on unified overall reference time t iLocal crystal oscillator signal be:ψ i(t)=exp{j((α′ 1w′ 1+α′ Nw′ N)t+λ′ 1+λ′ N)},i=1,2,...,N-1,N (33)λ ' wherein i=α ' iW ' iΔ ' i+ Φ ' i(4-9) according to spaced antenna B in above-mentioned bunch iLocal crystal oscillator frequency and the estimated value of phase place, obtain p bunch bunch in the spaced antenna set The synchronized result of local crystal oscillator signal be:(4-10) because p bunch bunch representative antennas and bunch representative antennas are accomplished the synchronous of local crystal oscillator with bunch representative antennas of other bunches in above-mentioned (3) step; So the P in the whole system bunch of M spaced antenna deadline Frequency Synchronization altogether is about to obtain in above-mentioned formula (18) the substitution formula (34) that the final synchronized result of all spaced antennas is in the whole system:
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