CN201479133U - Micropower wireless TD repeater - Google Patents
Micropower wireless TD repeater Download PDFInfo
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- CN201479133U CN201479133U CN2009203059162U CN200920305916U CN201479133U CN 201479133 U CN201479133 U CN 201479133U CN 2009203059162 U CN2009203059162 U CN 2009203059162U CN 200920305916 U CN200920305916 U CN 200920305916U CN 201479133 U CN201479133 U CN 201479133U
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- repeater
- gain
- self
- link
- excitation
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Abstract
The utility model relates to the field of supporting devices of the wireless network of a mobile communication system, in particular to a micropower wireless TD repeater. The micropower wireless TD repeater comprises a donor antenna, a transmission antenna, an uplink and a downlink, wherein the uplink and the downlink are arranged between the donor antenna and the transmission antenna in parallel. Each of the uplink and the downlink comprises a low-noise amplifier, an intermediate frequency module and a power amplifier, wherein the low-noise amplifier, the intermediate frequency module and the power amplifier are sequentially connected in series. The utility model is characterized in that a variable attenuator is arranged between the low-noise amplifier and the intermediate frequency module of any link of the uplink and the downlink, and the variable attenuator is connected with a gain detection comparison circuit. The utility model has the advantages that the self-excitation is actively and automatically eliminated but not the self-excitation is eliminated when the self-excitation has occurred or is to occur, and great convenience is provided for the installation of the wireless repeater.
Description
Technical field
The utility model relates to mobile communication system wireless network corollary equipment field, is specifically related to a kind of micropower wireless TD repeater.
Background technology
As shown in Figure 1, wireless discharging-directly station is a kind of with the audio amplifier system, and its course of work is as follows:
In down link, donor antenna is delivered to the repeater input with the base station signal that receives, and after amplify the repeater, is sent to the zone that needs covering by forwarding antenna.In up link, forwarding antenna receives the signal that mobile phone sends, and after amplify the repeater, is transmitted to the base station by donor antenna, finishes two-way communication.
Be example with the repeater down link below, the self-excitation phenomena of wireless discharging-directly station is described.
In down link, the signal that donor antenna reception base station signal is sent into the repeater is Sin, yet, the signal of forwarding antenna output is except issuing cell phone, also can be by the space coupling by way of feeding back to donor antenna, the signal that the feedback signal that donor antenna receives is sent into the repeater input is S ' in.The ratio of General Definition Sin and S ' in is the coefficient of stability Q of repeater, be Q=Sin/S ' in. when Sin and S ' in same-phase, satisfy the phase condition of amplifier self-oscillation. Sin＞S ' in when | Q|＞1, do not satisfy amplitude condition, amplifier can self-excitation; Sin≤S ' in when | Q|≤1, amplifier is unstable can to produce self-excitation, loses enlarging function.In order to make the repeater working stability, away from the self-excitation state, the general requirement | Q|=5～10
As shown in Figure 1, when repeater during as unidirectional amplifier, the repeater output signal is Sout, and the pass of Sout and Sin is
G＝Sout/Sin (1)
G in the formula (1) is the maximum linear gain of repeater
And the isolation I of wireless discharging-directly station is:
I＝Sout/S’in (2)
When straight-forward station self-excitation, having | Q|=1 promptly has Sin/S ' in=1 (3)
Bring formula (1) and formula (2) into formula (3), in the time of can obtaining straight-forward station self-excitation, have
G＝I (4)
So when the isolation I of wireless discharging-directly station equaled the repeater gain G, the repeater will self-excitation.In order not make the repeater produce self-excitation phenomena, generally require when carrying out the wireless discharging-directly station project installation, should guarantee that the isolation between the dual-mode antenna gains more than the 10dB greater than repeater equipment.
The method that increases isolation between the dual-mode antenna at present in the engineering has following several:
Increase horizontal range and vertical range between the dual-mode antenna
Increase shelter between the dual-mode antenna, as utilize body of wall to stop or install gauze screen etc. additional
Select stronger donor antenna of directivity and forwarding antenna for use
Adjust the angle and direction of dual-mode antenna, make both try one's best into 180 ° dorsad.
As can be seen, in order to eliminate self-excitation two kinds of methods can be arranged from wireless discharging-directly station self-exciting contion formula (4): a kind of is to make great efforts to increase isolation between the dual-mode antenna in engineering; Another kind is the gain that reduces the repeater, makes G＜I, thereby guarantees S ' in＜Sin, makes the repeater not produce self-excitation.After yet the repeater gain reduced, its power output also descended thereupon, and its coverage has also just and then been dwindled certainly, in general wireless discharging-directly station is used, was to adopt the method that reduces gain to eliminate self-excitation therefore.
Summary of the invention
The purpose of this utility model is according to above-mentioned the deficiencies in the prior art part, and a kind of micropower wireless TD repeater is provided, and gains by the equipment that reduces the repeater and eliminate the wireless discharging-directly station self-excitation in this repeater.Because the coverage of micro-power repeater is less, is about 100m
2～300m
2Area, the power output of coverage requirement micro-power repeater is original just little like this.Therefore, when reducing repeater gain elimination straight-forward station self-excitation,, can not produce obvious influence to the user though can make power output that decline is also arranged.
The utility model purpose realizes being finished by following technical scheme:
A kind of micropower wireless TD repeater, described wireless TD repeater comprises donor antenna, forwarding antenna and is arranged in parallel up link and down link between described donor antenna, forwarding antenna, described uplink and downlink link includes low noise amplifier, ifd module and the power amplifier of series connection successively, it is characterized in that connecting between the low noise amplifier in any link and ifd module in the described uplink and downlink link variable attenuator is set, described variable attenuator is connected with gain and detects comparison circuit.
Described gain detects and is set with the operation thresholding in the comparison circuit to control described variable attenuator.
Described gain detects the comparison circuit control connection indicator light.
The transmitting power of described down link is not less than 20mw; The transmitting power of described up link is not less than 10mw.
Described operation thresholding is lower than the maximum gain 1-2db of described repeater.
The utility model has the advantages that: automatic elimination self-excitation initiatively, rather than wait self-excitation to take place or just go to take measures to eliminate when being about to take place, bring very big convenience to the installation of wireless discharging-directly station.
Description of drawings
Fig. 1 is existing TD repeater principle schematic
Fig. 2 is the utility model principle schematic.
Embodiment
The utility model feature and other correlated characteristic are described in further detail by embodiment below in conjunction with accompanying drawing, so that technical staff's of the same trade understanding:
As shown in Figure 1, label 1-9 represents respectively: base station 1, donor antenna 2, forwarding antenna 3, power amplifier 4, ifd module 5, low noise amplifier 6, variable attenuator 7, gain detect comparison circuit 8, cell phone 9, indicator light 10.
Be example with the repeater down link equally, principle of the present utility model is as follows:
The maximum gain of supposing the repeater is G, and Sout is a peak power output, and under the peak power output state, maximum input signal is Sin, and the pass between the three is:
Sout＝Gsin (5)
After wireless discharging-directly station installed and opens, the repeater was when peak power output, and the operation of repeater reality gain will become G ', and the expression formula of G ' is
G’＝Sout/(Sin+S’in) (6)
S ' in is the interfering signal power that the space feeds back to the repeater input port in the formula (6).
Because the power control action, spiking output Sout is constant, and the signal of input has become Sin+S ' in, therefore can obviously find out, G '＜G, S ' in are bigger, and then G ' is just little.
When S ' in ≈ Sin, the value of G ' is
G’＝Sout/(Sin+S’in)＝Sout/2Sin＝1/2G (7)
By formula (7) as can be known, the repeater is during near the self-excitation state, and the operation of its reality gain has dropped to half (3dB has descended) of repeater equipment maximum gain.Therefore, we can be by the actual motion gain G after detecting the repeater and opening ' the decline degree estimate that wireless discharging-directly station opens the size of back isolation in installation, also can judge the degree of repeater in view of the above apart from the self-excitation state.
According to above analysis, can draw automatic elimination wireless discharging-directly station self-excitation method: when the isolation of repeater does not meet the demands, can be from detected repeater actual motion gain G ' the decline degree find out, so, we can manage to detect automatically G ' numerical value on the one hand, provide a control signal when dropping to the thresholding of setting, go to control automatically the equipment gain G of repeater, make it to descend, until G less than the isolation certain numerical value, till radio repeater system is eliminated self-excitation.
Because when self-excitation takes place in the repeater, might be that up link produces self-excitation, also might be down link produces self-excitation, or even the self-excitation simultaneously of uplink and downlink link.In the actual condition, the isolation of uplink and downlink link is more or less the same, and when engineering design in order to keep the balance of uplink and downlink link in the communication system, the actual motion gain G of uplink and downlink link ' also basic identical.So can choose a road link in the uplink and downlink link arbitrarily as Self-excitation Detection, elimination.
As shown in Figure 2, be example with the down link, the technical scheme of present embodiment is as follows:
Direct amplifying station device among the utility model embodiment comprises donor antenna 2, forwarding antenna 3 and being arranged in parallel in described donor antenna 2, up link between the forwarding antenna 3 and down link, on described, down link includes the low noise amplifier 6 of series connection successively, ifd module 5 and power amplifier 4, between the low noise amplifier 6 of described down link and ifd module 5, connect variable attenuator 7 is set, described variable attenuator 7 is connected with gain and detects comparison circuit 8, and described gain detects in the comparison circuit 8 has the operation thresholding according to described repeater equipment parameter setting.Gain detection comparison circuit 8 also control connection has indicator light 10, and indicator light 10 is opened when variable attenuator is regulated the gain of 8 repeater equipments, to play suggesting effect.
The transmitting power of micropower wireless TD repeater described above has following requirement: the transmitting power of down link is not less than 20mw; The transmitting power of up link is not less than 10mw.
In conjunction with the said apparatus structure, below be elaborated for the operation principle of installing in the present embodiment:
After wireless discharging-directly station installs and opens, detect the size of power output Sout and input signal Si n+S ' in, in gain detection comparison circuit, calculate direct discharging station actual motion gain G ', and compare with the repeater equipment gain G, set the operation thresholding if the actual motion gain is reduced to, control variable attenuator 7 reduces described repeater equipment gain; The actual motion gain rises to be set on the thresholding, the described repeater equipment gain of control variable attenuator 7 risings.And when variable attenuator 7 operations, open indicator light 10 to play suggesting effect.
G ' is provided with thresholding for example
Suppose: repeater equipment maximum gain G=80
DB
Repeater peak power output Sout=30
DBm
Repeater maximum input level Sin=-50
DB ' m
As isolation I=90
DBThe time,
Feedback signal level S ' in=-60
DBm, the actual output level in repeater is
Sin+S’in＝(-50
dBm)+(-60
dBm)
＝-49.6
dBm
At this moment, G '=30
DBm-(49.6)=79.6
DBm
When isolation is respectively 85
DB, 83
DB, and 80
DBThe time, result of calculation is as shown in table 1:
Table 1
| Isolation I | Feedback signal S ' in | Input signal Si n+S ' in | Actual motion gain G ' |
| 90 dB | -60 dBm | -49.6 dBm | 79.6 dB |
| 85 dB | -55 dBm | -48.9 dBm | 78.9 dB |
| 83 dB | -53 dBm | -48.2 dBm | 78.2 dB |
| 80 dB | -50 dBm | -47 dBm | 77 dB |
In this example, if G ' slave unit maximum gain 80 is set
DBDrop to 79
DBThe time, indicator light 10 provides indication, and sends control signal simultaneously and give variable attenuator 7, regulates the repeater equipment gain G and descends, and extinguishes up to indicator light 10, and gain-adjusted finishes, and then isolation is approximately 85
DB, promptly isolation I is than the equipment gain 79 after descending
DBBig by 6
DB
As from the foregoing, the operation thresholding of regulating and controlling repeater equipment gain G can be set according to the maximum gain (for the known desired value of dispatching from the factory) of repeater equipment.The general operation thresholding of setting be to reduce by 1～2db than equipment maximum gain, and the isolation between antennas of this moment is than the equipment big 5～3db that gains, and the repeater is worked more stable, generally can not produce self-excitation.If it is some more that the setting thresholding descends again, the repeater is just nearer from the self-excitation state.Obviously, after the decline of repeater equipment gain G also might occurring regulating, the operation gain G ' still continue to descend and the situation of self-excitation occurs, so a series of operation thresholding also can be set, continue adjusting repeater equipment gain G according to some thresholdings of setting and avoid occurring the self-excitation situation.
Traditional indoor distributed system all is with solving than large tracts of land indoor signal blind area and weak signal zone covering problem, to less than 100m
2～300m
2Following indoor signal blind area, because the Financial cost factor, traditional indoor distributed system can't well solve.So the signal blind zone of these fritters has become the last blind spot of mobile communications network, arrival along with the 3G epoch, since when 3G is professional special 70%～80% of high-end business all occur in indoor, the covering problem that solves these numerous little fast indoor signal blind areas will become many people's demand, get a little flexible, be convenient to install with cheap micro-power repeater equipment in, the repeater can be detected at any time and the self-excitation situation may be produced, and can eliminate self-excitation harm by the method for automatic reduction equipment gain, thereby the installation and the difficulty of construction of repeater have been reduced, improve network communication quality, also just enlarged the application prospect of micro-power repeater.
Claims (5)
1. micropower wireless TD repeater, described wireless TD repeater comprises donor antenna, forwarding antenna and is arranged in parallel up link and down link between described donor antenna, forwarding antenna, described uplink and downlink link includes low noise amplifier, ifd module and the power amplifier of series connection successively, it is characterized in that connecting between the low noise amplifier in any link and ifd module in the described uplink and downlink link variable attenuator is set, described variable attenuator is connected with gain and detects comparison circuit.
2. a kind of micropower wireless TD repeater according to claim 1 is characterized in that being set with the operation thresholding to control described variable attenuator in the described gain detection comparison circuit.
3. a kind of micropower wireless TD repeater according to claim 1 is characterized in that described gain detects the comparison circuit control connection indicator light is arranged.
4. a kind of micropower wireless TD repeater according to claim 1 is characterized in that the transmitting power of described down link is not less than 20mw; The transmitting power of described up link is not less than 10mw.
5. a kind of micropower wireless TD repeater according to claim 2 is characterized in that described operation thresholding is lower than the maximum gain 1-2db of described repeater.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009203059162U CN201479133U (en) | 2009-07-09 | 2009-07-09 | Micropower wireless TD repeater |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009203059162U CN201479133U (en) | 2009-07-09 | 2009-07-09 | Micropower wireless TD repeater |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201479133U true CN201479133U (en) | 2010-05-19 |
Family
ID=42415388
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2009203059162U Expired - Lifetime CN201479133U (en) | 2009-07-09 | 2009-07-09 | Micropower wireless TD repeater |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201479133U (en) |
-
2009
- 2009-07-09 CN CN2009203059162U patent/CN201479133U/en not_active Expired - Lifetime
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C56 | Change in the name or address of the patentee |
Owner name: SHANGHAI BEIDIAN INDUSTRY (GROUP) CO., LTD. Free format text: FORMER NAME: SHANGHAI BEIDIAN INDUSTRY CO., LTD. |
|
| CP01 | Change in the name or title of a patent holder |
Address after: 201206 floor, building D, No. 501 Jinqiao Jin Road, Shanghai, Pudong New Area, China Patentee after: Shanghai Bei Dian electric industry (Group) Co., Ltd. Address before: 201206 floor, building D, No. 501 Jinqiao Jin Road, Shanghai, Pudong New Area, China Patentee before: Shanghai Beidian Industry Co., Ltd. |
|
| CX01 | Expiry of patent term |
Granted publication date: 20100519 |
|
| CX01 | Expiry of patent term |