Background technology
Along with the continuous increase of communication requirement, cordless communication network is almost ubiquitous, and frequency resource day is becoming tight, and the phase mutual interference producing thus between wireless system is inevitable.The working frequency range of GSM-R is up 885~889MHz; Descending 930~934MHz; Adjacent have China Telecom, China Mobile and a CHINAUNICOM, specifically sees the following form:
The interference of GSM-R base station radio-frequency mainly contains following several:
1) uplink interference: according to table one, GSM-R base station uplink band is vulnerable to the descending interference of telecommunications CDMA800 and the second harmonic of the DCS1800 of mobile UNICOM disturbs, causes the QOS quality of reception of base station to decline, and effective coverage range reduces.
2) co-channel interference: while referring to channeling, the interference between same frequency community, along with system scale constantly expands, channeling degree improves, and co-channel interference must increase.
3) barrage jamming: the strong signal of receiving belt outward flange, make receiver amplifier saturated, can not normally receive signal.
4) Intermodulation Interference: Intermodulation Interference is to enter receiving equipment by the one or more radio signal source in outside through antenna, because the non-linear inter-modulated signal that produces new frequency of receiving unit device is disturbed.
Utility model content
The utility model is in order to solve the problem of prior art, a kind of high GSM-R base station suppressing of interference signal that has is provided, compression GSM-R base station receives bandwidth, reduce the end level of making an uproar, the outer large-signal of inhibition zone is disturbed, prevent that GSM-R base station transceiver from blocking, and can effectively reduce intermodulation GSM-R base station transceiver is disturbed.
The utility model comprises base station transceiver BTS and antenna thereof, a pair of dual band pass filter or a pair of dual band pass GSM-R coupler are housed between base station transceiver BTS and antenna, described dual band pass filter or dual band pass GSM-R coupler comprise high-frequency signal insert port RFin and radiofrequency signal mouth RFout, high-frequency signal insert port RFin is N-K radio-frequency maser, connect 1/2 feeder line, be connected with GSM-R base station, radiofrequency signal mouth RFout is L29(7/8)-K radio-frequency maser, connect 7/8 feeder line, be connected with antenna.
The up passband F UL=885~889MHz of described dual band pass filter or dual band pass GSM-R coupler, frequency Out-of-band rejection > 30dBc beyond uplink receiving frequency range edge 2MHz, frequency > 50dBc beyond@edge 5MHz, insertion loss < 1.0dB; Descending passband F DL=930~934MHz, downstream filtering frequency range insertion loss is less than 0.5dB.
Described dual band pass GSM-R coupler has coupling port Couple, and coupling port Couple is N-K radio-frequency maser, connects GSM-R direct discharging station, and the degree of coupling is 20dB, 30dB, 35dB or 40dB.
The utility model beneficial effect is: by dual band pass filter or dual band pass GSM-R coupler, compress GSM-R base station and received bandwidth, reduce the end level of making an uproar, having suppressed the outer large-signal of band disturbs, prevent that GSM-R base station transceiver from blocking, and effectively reduced intermodulation GSM-R base station transceiver is disturbed.
Brief description of the drawings
Fig. 1 is the structural representation that base station connects dual band pass filter.
Fig. 2 is dual band pass filter construction schematic diagram.
Fig. 3 is the structural representation that base station connects dual band pass GSM-R coupler.
Fig. 4 is dual band pass GSM-R coupler structure schematic diagram.
Fig. 5 is dual band pass filter or dual band pass GSM-R coupler signal suppressing curve chart
Fig. 6 is the dual band pass filter data feedback channel schematic diagram of single chamber design.
Fig. 7 is dual band pass filter data feedback channel signal suppressing curve chart
Fig. 8 is the dual band pass filter down going channel schematic diagram of single chamber design.
Fig. 9 is dual band pass filter down going channel signal suppressing curve chart.
Figure 10 is dual band pass GSM-R coupler data feedback channel signal suppressing curve chart.
Figure 11 is dual band pass GSM-R coupler down going channel signal suppressing curve chart.
Embodiment
Below in conjunction with accompanying drawing, the utility model is described in further detail.
Dual band pass filter construction as shown in Figure 3, comprises high-frequency signal insert port RFin and radiofrequency signal mouth RFout.In the time that base station connects dual band pass filter, structure as shown in Figure 1.High-frequency signal insert port RFin is N-K radio-frequency maser, connects 1/2 feeder line, is connected with GSM-R base station, and radiofrequency signal mouth RFout is L29(7/8)-K radio-frequency maser, connect 7/8 feeder line, be connected with antenna.
Dual band pass GSM-R coupler structure as shown in Figure 4, comprises high-frequency signal insert port RFin, radiofrequency signal mouth RFout and coupling port Couple.In the time that base station connects dual band pass GSM-R coupler, structure as shown in Figure 2.。High-frequency signal insert port RFin is N-K radio-frequency maser, connects 1/2 feeder line, is connected with GSM-R base station.Radiofrequency signal mouth RFout is L29(7/8)-K radio-frequency maser, connect 7/8 feeder line, be connected with antenna.Coupling port Couple is N-K radio-frequency maser, connects GSM-R direct discharging station by electric bridge.
Filter or coupler adopt dual band pass cavity body structure, up passband F
uL=885~889MHz; Descending passband is F
dL=930~934MHz.GSM-R base station is mainly considered to the Out-of-band rejection of uplink receiving passband, eliminated uplink interference, therefore the up passband Out-of-band rejection requirement of GSM-R base station filter or coupler is high, is mainly that in band, Insertion Loss is low, as shown in Figure 5 to the requirement of descending passband.
The squareness factor of filter or coupler is relevant with Insertion Loss, be that edge is steeper, insertion loss is larger, disturb larger place in base station, often receive signal all very strong, noise of equipment coefficient is less important, Out-of-band rejection is main, but for downlink signal, can not affect transmitting power, be main so descending for insertion loss index.
According to the service condition of base station filter or coupler, require its uplink receiving frequency range Out-of-band rejection > 30dBc(@edge 2MHz frequency in addition), frequency beyond > 50dBc(@edge 5MHz), insertion loss can be loosened to < 1.0dB;
Downstream filtering frequency range Out-of-band rejection index request is not high, but insertion loss is required to be less than 0.5dB.
The design parameter index of dual band pass filter is as follows:
The data feedback channel FU=885-889MHz of dual band pass filter.
1, adopt the design of single chamber, as shown in Figure 6: single chamber diameter 53mm, the dark 44mm in chamber, nonloaded Q 4674, consideration machine adds and electroplates the impact of factor, and it is 4206 that nonloaded Q is multiplied by 0.9 scale factor.
2, adopt 9 chamber designs at 4 zero point, consideration machine adds and electroplates the impact of factor, and nonloaded Q is multiplied by 0.9 scale factor, and Q value 4206 is brought into coupling matrix, for ensureing loss and high low temperature offset target surplus, bandwidth is widened to 6.7MHz, by 4MHz as shown in Figure 7.
The down going channel FD=930-934MHz of dual band pass filter.
1, adopt the design of single chamber, as shown in Figure 8: single chamber diameter 35mm, the dark 44mm in chamber, nonloaded Q 3616, as figure below: consideration machine adds and electroplates the impact of factor, and it is 3254 that nonloaded Q is multiplied by 0.9 scale factor.
2, adopt 4 chamber Natural Attenuation designs, consideration machine adds and electroplates the impact of factor, and nonloaded Q is multiplied by 0.9 scale factor, and Q value 3254 is brought into coupling matrix, for ensureing loss and high low temperature offset target surplus, bandwidth is widened to 14MHz, by 4MHz as shown in Figure 9.
The design parameter index of dual band pass coupler is as follows:
Dual band pass GSM-R coupler data feedback channel FU=885-889MHz.Adopt 8 chambeies 4 to fly bar design, nonloaded Q 4200, for ensureing loss and high low temperature offset target surplus, widens bandwidth to 7MHz, by 4MHz as shown in figure 10.
Dual band pass GSM-R coupler down going channel FD=930-934MHz.Adopt 4 single chamber Natural Attenuation designs, nonloaded Q 3200, for ensureing loss and high low temperature offset target surplus, widens bandwidth to 14MHz, by 4MHz as shown in figure 11.
The concrete application approach of the utility model is a lot; the above is only preferred implementation of the present utility model; should be understood that; for those skilled in the art; do not departing under the prerequisite of the utility model principle; can also make some improvement, these improve and also should be considered as protection range of the present utility model.