Smart antenna implementation method and device based on digital beam formation
Technical field
The present invention relates to the intelligent antenna technology of moving communicating field.
Background technology
Since the nineties, the ARRAY PROCESSING technology is introduced moving communicating field, has formed a new research focus-smart antenna very soon.Smart antenna improve system communication quality, alleviate radio communication growing with the frequency spectrum resource deficiency contradiction, reduce the entire system cost and improve aspect such as system management, all have the advantage of uniqueness.Initial intelligent antenna technology is mainly used in radar, sonar, military antijam communication, is used for finishing space filtering and location etc.In recent years, go deep into gradually along with the development of mobile communication and to the research of aspects such as mobile communication radio wave propagation, networking technology, antenna theory, the development of modern digital signal processing technology is rapid, and therefore intelligent antenna technology is used to have the mobile communication of complicated radio propagation environment.The essence of smart antenna is under the situation that does not increase system complexity, can satisfy the needs of the service quality and the network capacity extension.In fact it makes the communication resource no longer be confined to time-domain (TDMA), frequency domain (FDMA) or sign indicating number territory (CDMA) and has been extended to spatial domain, belongs to space division multiple access (SDMA) system.
At present, a lot of about the theoretical algorithm of smart antenna, multiple sorting technique is arranged, on the wave beam control forms, can be divided into switched-beam and adaptive beam two big classes.Switched-beam switches based on wave beam.Adaptive beam is adjusted automatically based on wave beam.The complexity of intelligent algorithm, performance, realizability and and Several Key Problems such as conventional system compatibility be that intelligent antenna technology is badly in need of problem to be solved.
At United States Patent (USP) United States Patent 6,236,866, the thought of adaptive antenna pattern control has been proposed in " Adaptive antennapattern control for a multiple access communication system ".Discussed the advantage of this method that adopt in the patent, can reach " cell breathing " automatically, do not discussed the specific implementation method for the CDMA communication system.The SPOTLIGHT system of Metawave company realizes that at radio frequency wave beam forms, and does not have the base band wave beam to form flexible configuration.More external scholars propose some smart antenna algorithms.As: Least SquaresDe-spread Respired Multitarget Array (LS-DRMTA), Least SquaresDe-spread Re-spread Multitarget Constabt ModulusAlogorithmArray (LS-DRMTCMA), from S.Rappaport, J.Liberti, " SmartAntennas for Wireless Communications:IS-95 and Third Generation CDMAApplications ", also has Piolt Symol-Assisted Decision-Directed CoherentAdaptive Array Diversity for DS-CDMA Mobile Radio Reverse Link, a difficulty from IEICE TRANS.FUNDANENTALS.1997. said method is that algorithm complex is higher, in order to satisfy the real-time of algorithm, convergence, cause the base station cost too high, even under present device level, can't realize.Needs such as additional information that needs in these algorithms such as multidiameter delay change the structure and the application mode of baseband processor, and simultaneously, switching, Radio Resource control and management also need to upgrade.These variations cause the structure of antenna system and non intelligent antenna system different, have limited flexibility and the compatibility used.
Summary of the invention
The invention provides a kind of smart antenna implementation method and device that forms based on digital beam.
A kind of smart antenna implementation method that forms based on digital beam may further comprise the steps:
A) configuration application mode of intelligent beam;
B) configuration wave beam weight;
C) wave beam forms, conventional Base-Band Processing;
D) cell business volume is weighed and link test;
E) according to step D) measurement parameter, upgrade wave beam weight.
Above-mentioned application mode of intelligent beam has two kinds: handle and the application mode of diversity technique and based on the application mode of diversity, traffic balance based on compromise traffic balance, spatial domain.
The present invention is based on the smart antenna implementation method that digital beam forms, also include the application mode updating steps, according to above-mentioned steps D) each cell business volume of weighing and link evaluate parameter determine that the current application mode of system is based on the application mode of compromise traffic balance, spatial domain processing and diversity technique or based on the application mode of diversity, traffic balance, so that improve systematic function better.
A kind of smart antenna implement device that forms based on digital beam comprises: array diversity antenna, radio-frequency channel, wave beam form unit, Base-Band Processing MODEM and beam-controller; Array diversity antenna replaces antenna to finish the reception of cell/section, and each array element of array diversity antenna connects a radio-frequency channel, finishes the conversion of radio frequency to baseband signal; The zero intermediate frequency baseband signal enters wave beam formation unit and finishes digital beam formation, finishes the conversion of array element territory signal to wave beam territory signal; With the conventional array element signals of the corresponding one-tenth of wave beam territory signal, be input to the antenna input of base station baseband MODEM, finish up process; The user profile that descending process is come out from base band MODEM forms the unit through downlink wave beam signal map is arrived the array element territory, launches through each radio-frequency channel and array antenna again, finishes descending process; The parameter that wave beam forms is obtained through the traffic balance criterion by beam-controller.
Described array antenna is formed a submatrix by 2~4 array elements, and diversity between two submatrixs.
Described diversity is space diversity or polarization diversity.
Described wave beam forms the unit and comprises that uplink beam forms the unit and downlink wave beam forms the unit.
Described uplink beam forms the unit and comprises two groups of multiply-add operation devices.
Described downlink wave beam forms the unit and comprises four complex multipliers and two accumulators.
The present invention utilizes the implementation method of conventional baseband processing unit realization based on the smart antenna of digital beam formation, can realize that traffic balance is to improve network capacity and to reduce and disturb, make antenna system can flexible configuration and and conventional base station compatible, cost performance and autgmentability are preferably arranged, between algorithm performance and algorithm realization property, obtain compromise.It is simple to have system configuration, and realizability is good, is easy to and characteristics such as existing system smooth connection.
Description of drawings
Fig. 1 forms the flow chart of smart antenna implementation method for digital beam of the present invention.
Fig. 2 is applied to a kind of enforcement block diagram in the WCDMA system for the present invention.
The array junctions composition that Fig. 3 adopts for the embodiment of the invention.
The uplink baseband wave beam that Fig. 4 adopts for the embodiment of the invention forms implements block diagram.
The downgoing baseband wave beam that Fig. 5 adopts for the embodiment of the invention forms implements block diagram.
Fig. 6 implements block diagram for the another kind that the present invention is applied in the WCDMA system;
Embodiment
The present invention is based on flow chart that digital beam forms the smart antenna implementation method as shown in Figure 1.
Step 101: beginning;
Step 102: configuration application mode;
Step 103: configuration wave beam weight;
Step 104: wave beam forms, conventional Base-Band Processing;
Step 105: each cell business volume is weighed;
Step 106: link performance assessment;
Step 107:, upgrade wave beam weight according to algorithm and above-mentioned measurement parameter;
Step 108:, upgrade application mode according to algorithm and measurement parameter.
The configuration application mode of step 102 has two kinds: handle and the application mode of diversity technique and based on the application mode of diversity, traffic balance based on compromise traffic balance, spatial domain.During beginning, be appointed as wherein a kind of.
The configuration wave beam weight of step 103, the fixing weights of initialization have just been begun to be, the back is carried out right value update according to step 105,106 each cell business volume and the link evaluate parameters of weighing according to each Zone balance criterion by step 107, promptly realize traffic balance by the covering that changes the sub-district, wave beam weight is determined according to desired direction of wave beam and width.
Each cell business volume that step 108 is weighed according to step 105,106 and link evaluate parameter determine the current application mode of system be based on the application mode of compromise traffic balance, spatial domain processing and diversity technique or based on the application mode of diversity, traffic balance so that improve systematic function better.
Implementation method provided by the invention has following characteristics:
1) flexible wave beam changes the covering shape of sector, even can further change the covering shape of whole sub-district, thus the balance traffic carrying capacity, and the dynamic optimization network planning improves network capacity;
2) utilize 1~2 wave beam that generates in advance to cover whole sector, that is to say that a sector is to be covered by 1~2 narrow beam, because the use of narrow beam then can reduce other users' interference.
The array structure that the present invention adopts as shown in Figure 3.Use 3 group of 2 array element line array+2 array element line array (two antenna array air line distance 7 more than the wavelength), submatrix array element is 0.5 wavelength at interval.
Fig. 2 is applied to a kind of enforcement block diagram (Baseband Modem be with CSM5200 example explanation) in the WCDMA system for the present invention.Form by following modules: array element 21, data feedback channel 22, uplink beam forms 23, Base-Band Processing 24, downlink wave beam forms 25, down going channel 26, as shown in Figure 2.
Corresponding 6 sectors of this kind application mode, shared 4 antennas in per 2 sectors, two submatrixs form 4 narrow beams a sector, submatrix (array element 2101,2102 compositions, array element 2105,2106 compositions, array element 2109,2110 compositions) form unit (231 by uplink beam respectively, 233,235) 2 narrow beams of each self-forming (claiming that these 2 wave beams are main beam), submatrix (array element 2103,2104 compositions, array element 2107,2108 compositions, array element 2111,2112 compositions) form unit (232 by uplink beam respectively, 234,236) also form 2 narrow beams (claiming that these 2 wave beams are the spoke wave beam) that have identical coverage with main beam.When up, array element 21 received RF signals, obtain the IQ baseband signal through 12 data feedback channels 22, form unit 23 by the wave beam of 62 array elements again and form corresponding 6 sectors of 12 wave beams altogether, 6 main beams and 6 spoke wave beams are arranged, and main beam is identical with the coverage of spoke wave beam, main beam is sent into the main antenna input of CSM5200, send into the corresponding spoke antenna input of CSM5200 with the identical spoke wave beam of main beam coverage, carry out other base band signal process; Descending, the main beam wave beam is sent in the output of CSM5200 main antenna formed unit (251,253,255), and the spoke wave beam is sent in the output of CSM5200 spoke antenna formed unit (252,254,256), form the signal of corresponding down going channel 26, launch the formation spatial beams by array element 21 again; Beam processor 27 will be adjusted beam position and width according to the traffic balance criterion, thereby the balance traffic carrying capacity improves network capacity.
Uplink beam among Fig. 2 forms as shown in Figure 4.For example the uplink beam among Fig. 2 forms 41,42 liang of group multiply-add operation devices that unit 231 comprises Fig. 4, and uplink beam forms 43,44 liang of group multiply-add operation devices that unit 232 comprises Fig. 4.Comprise 411,412 two complex multipliers in 41 arithmetic units, its coefficient is w
0=(w
00, w
01), by the outside input, determine that according to the sensing and the width of required wave beam this coefficient is wave beam weight, 413 is accumulator.
Downlink wave beam among Fig. 2 forms the unit as shown in Figure 5.For example the downlink wave beam among Fig. 2 forms 531,532 accumulators in the adder calculator 53 of 511,512,513,514 4 complex multipliers in the multiplicative operator 51 that unit 251 comprises Fig. 5 and Fig. 5, the coefficient w in the multiplicative operator 51
0=(w
00, w
01), w
1=(w
10, w
11) by the outside input, determine that according to the sensing and the width of required wave beam definite method of its coefficient is the same.
The control of uplink and downlink wave beam forming is finished in wave beam control 27 among Fig. 2.Wave beam forming can be according to the traffic carrying capacity balance, artificial set, high-rise feedback, algorithm etc. is controlled when empty.
Wave beam forms 231 ... 233 owing to finish in base band, and therefore application mode is very flexibly arranged.The applied environment that the different application mode is corresponding different.Fig. 2 is a kind of typical application mode.The advantage of this mode is that handle and diversity technique in compromise traffic balance, spatial domain.
The present invention shown in Figure 6 is applied to another the enforcement block diagram (Baseband Modem is the example explanation with CSM5200) in the WCDMA system.Up based on diversity, traffic balance.
Corresponding 3 sectors of this kind application mode, when up, array element 61 received RF signals, obtain the IQ baseband signal through 12 data feedback channels 62, form unit 63 by the wave beam of 62 array elements again and form corresponding 3 sectors of 6 wave beams altogether, 3 main beams and 3 spoke wave beams are arranged, and main beam is identical with the coverage of spoke wave beam, main beam is sent into the main antenna input of CSM5200, send into the corresponding spoke antenna input of CSM5200 with the identical spoke wave beam of main beam coverage, carry out other base band signal process; Descending, main beam is sent in the output of CSM5200 main antenna formed unit (651,653,655), and the spoke wave beam is sent in the output of CSM5200 spoke antenna formed unit (652,654,656), form the signal of corresponding down going channel 66, launch the formation spatial beams by array element 61 again; Beam processor 67 will be adjusted beam position and width according to the traffic carrying capacity size of estimating, thereby the balance traffic carrying capacity improves network capacity.
Implement device provided by the invention has following features:
1) easily realization and system configuration are flexible. Yu the present invention has taken into full account the characteristics of GSM, Therefore it is simple to have system architecture, and realizability is good, be easy to and the existing system smooth connection, but the base station root Be configured to Zhi energy communication base station, conventional base station or the mixture of the two according to needs.
2) compatible good. The diversity technique of method provided by the invention is preferably compatible conventional system and the time The You point that Yu processes is processed three aspects from airspace filter processing, time domain processing and diversity and is jointly improved system The system processing gain.
3) cost performance is good. The application of You Yu this method maximum limit degree existing treatment technology and equipment, better Take into account cost, performance, thereby be with a wide range of applications.