Source: https://patents.google.com/patent/EP0993124A2/en
Timestamp: 2018-07-20 18:48:32
Document Index: 191323867

Matched Legal Cases: ['Application No. 4', 'art 12', 'art 15', 'art 10', 'arts 11', 'art 13', 'art 14', 'art 15', 'art 10', 'art 10', 'art 10', 'art 15', 'art 10', 'arts 11', 'art 13', 'art 14', 'art 15', 'art 15', 'art 60', 'arts 61', 'arts 63', 'art 65', 'art 66', 'arts 67', 'art 60', 'art 60', 'art 66', 'arts 67', 'art 60', 'arts 61', 'arts 63', 'art 65', 'art 66', 'art 67', 'art 68', 'art 131', 'art 133', 'art 132', 'art 134', 'art 134', 'art 134', 'art 134', 'art 131', 'art 132', 'art 134', 'art 134', 'art 134', 'art 134', 'art 134', 'art 134', 'art 134', 'art 134', 'art 133', 'art 133', 'art 133']

EP0993124A2 - Radio signal transmitter in two frequency bands with and without power limitation - Google Patents
Radio signal transmitter in two frequency bands with and without power limitation Download PDF
EP0993124A2
EP0993124A2 EP19990111994 EP99111994A EP0993124A2 EP 0993124 A2 EP0993124 A2 EP 0993124A2 EP 19990111994 EP19990111994 EP 19990111994 EP 99111994 A EP99111994 A EP 99111994A EP 0993124 A2 EP0993124 A2 EP 0993124A2
EP19990111994
EP0993124B1 (en )
EP0993124A3 (en )
Kouchi Masuda
Susumu Morikura
A signal including an RF signal and a code division multiple access signal is transmitted so that, in relation to both of the RF signal and the code division multiple access signal, a receiving end can obtain a signal having sufficiently larger power as compared with noise and with no distortion. In order to attain this object, a separation part (10) separates the signal into the RF signal and the code division multiple access signal at a sending end. An amplification part (11) amplifies the RF signal with an amplification factor related to its power. An amplification part (12) amplifies the code division multiple access signal with an amplification factor related to its power. A combination part (13) combines the amplified RF signal and the amplified code division multiple access signal with each other.
FIG. 13 is a block diagram showing an exemplary structure of a conventional optical transmission system employed in the aforementioned radio base station for optically transmitting a signal between the master station and the slave station. This type of optical transmission system is described in "Fiber-Optic Transmission System for Radio Base Stations" (Sanada et al., National Technical Report Vol. 39, No. 4, Aug. 1993), for example.
As described in "CDMA Cellular System" (Association of Radio Industries and Businesses, ARIB STD-T53 Version 1.0), in relation to mobile communication, as lines rapidly increases in number in recent years, there has been proposed employment of the CDMA (code division multiple access) system having a remarkably larger number of lines as compared with the conventional system. Recently mobile communication in the CDMA system is in part put into practice, and it is predicted that hereafter the ratio of the CDMA system occupying the mobile communication increases.
The standards of the current system are described in "Digital Cellular Telecommunication System" (Research & Development Center for Radio Systems, RCR STD-27A) and the standards of the CDMA system are described in the aforementioned "CDMA Cellular System". An apparatus optically transmitting a code division multiple access signal is disclosed in Japanese Patent Laying-Open No. 6-70362 (Japanese Patent Application No. 4-219894), for example.
In the aforementioned structure of the slave station 300. the difference in the distances between the respective mobile terminals and the slave station 300 results in remarkable difference in received power received in the antenna 306. Therefore, the conventional radio signal transmitter employs in consideration of this difference in received power an extremely wide dynamic range for the signal of the up system and sets the optical modulation index per wave high.
An exemplary system design of this slave station 300 is described in the above-mentioned literature "Fiber-Optic Transmission System for Radio Base Stations" by Sanada et al. In this literature by Sanada et al., the optical modulation index m of the up system is, assuming that the up system has two carriers, 10.7 % ≦ m ≦ 21.2 %. The lower limit and the upper limit of this optical modulation index m are decided respectively by carrier-to-noise ratio (CNR) characteristics and distortion characteristics.
FIG. 15 shows the relation between the optical modulation index, CNR and distortion (in this case, "distortion IM3" which is tertiary distortion).
As understood from FIG. 15, the CNR increases with increase of the optical modulation index, and the distortion IM3 is degraded by the increase of the optical modulation index. First the optical modulation index at the lower limit is decided by a value satisfying CNR = 80 dB, and the current value of the optical modulation index is 10.7 %. On the other hand, the optical modulation index at the upper limit is decided by a value satisfying distortion IM3 = -84 dBc, and the current optical modulation index is 21.2 %. This distortion IM3 = -84 dBc is, assuming that the distortion characteristic in the overall transmitter is -80 dBc a distortion quantity which can be allowed by a semiconductor laser diode (LD) module employed as an optical/electrical conversion part in an optical sender.
The relation between the aforementioned composite number and the carrier number is, as described in literature "Optical Feeder Basic System Design for Microcellular Mobile Radio" by Junji Namiki et al. (IEICE TRANS. COMMUN., VOL. E76-B, No.9 September 1993, pp. 1069 to 1077), obtained by the following equation (1): Nc = M*(N - M + 1)/2 + ((N - 3)2 - 5) - (1 - (-1))-N*(-1)N+M
As to the relation between the distortion IM3 and the distortion CTB in the same frequency band, assuming that D2 [dBc] represents the distortion IM3 caused when transmitting two carriers having a optical modulation index m2 [%] and DN [dBc] represents the distortion CTB caused when transmitting N carriers having a optical modulation index mN [%] of the same transmission system, DN is estimated with the composite number Nc in the following equation (2): DN = D2 + 10*log(Nc) + 2*20*log(mN/m2)
Assuming that the value D2 of the distortion IM3 when mN = 10.7 % and 21.2 % and m2 = 20 % is -85 dBc, the relation between the distortion quantity DN and the composite number when mN = 10.7% and 21.2 % can be obtained from the above equation (2). FIG. 17 shows this relation. Obtaining from FIG. 17 a composite number satisfying -84 dBc which is the spec of the distortion characteristic DN of an LD module, it becomes "15" when mN = 10.7% and becomes "1" when mN = 21.2 %. Further, the carrier number can be obtained from the relation between the composite number and the carrier number shown in FIG. 16, such that the carrier number becomes "8" carriers when the modulation factor is 10.7%, and becomes "3" carriers when the modulation factor is 21.2 %.
FIG. 11 is a diagram showing exemplary relation between frequencies of signals received in a first antenna 36a and a second antenna 36b and received power;
FIG. 2 is a schematic diagram showing an exemplary radio base station, to which the system of FIG. 1 is applied, for performing mobile communication by both of the current system and the CDMA system. Referring to FIG. 2, the radio base station is formed by a master station 20 without an antenna 21a and one or more slave stations 21 each having an antenna 21a. The one or more slave stations 21 are dispersively arranged as forward stations in a blind zone or the like, and the master station 20 and each slave station 21 are connected to each other by an optical fiber 22.
The amplification part 12 performs amplification with such an amplification factor that the power of the code division multiple access signal included in the output signal from the optical/electrical conversion part 15 becomes sufficiently larger than that of noise. Thus, the receiving end can obtain a code division multiple access signal having sufficiently large power as compared with noise (i.e., having an excellent C/N ratio).
FIG. 4 is a block diagram showing an exemplary structure of the radio base station of FIG. 2 to which the optical transmission system of FIG. 1 is applied. FIG. 4 shows elements necessary when transmitting a signal from the slave station 21 to the master station 20. Referring to FIG. 4, the slave station 21 comprising the antenna 21a is provided with the separation part 10, the amplification parts 11 and 12, the combination part 13 and the electrical/optical conversion part 14 of FIG. 1, and the master station 20 is provided with the optical/electrical conversion part 15.
In a talking area of the slave station 21, a mobile terminal for the current system and a mobile terminal for the CDMA system are mixedly provided (not shown). From these mobile terminal sides, an RF signal and a code division multiple access signal are sent toward the slave station 21. In the slave station 21, these RF signal and code division multiple access signal are received by the antenna 21a and inputted in the separation part 10. The separation part 10 separates the input signal including the RF signal and the code division multiple access signal into the RF signal and the code division multiple access signal.
Also when providing in place of the antenna 21a and the separation part 10 an antenna for the RF signal and an antenna for the code division multiple access signal, the input signal can be branched into two signals. That is, by the antenna for the RF signal and the antenna for the code division multiple access signal, a signal separating function similar to the above can be implemented.
FIG. 6 is a block diagram showing another exemplary structure of the radio base station of FIG. 2 to which the optical transmission system of FIG. 1 is applied. FIG. 6 shows elements necessary when transmitting a signal from the master station 20 to the slave station 21. Referring to FIG. 6, the slave station 21 comprising the antenna 21a is provided with the optical/electrical conversion part 15 of FIG. 1, and the master station 20 is provided with the separation part 10, the amplification parts 11 and 12, the combination part 13 and the electrical/optical conversion part 14.
The optical signal outputted from the master station 20 in the aforementioned manner propagates in the optical fiber 22 and reaches the slave station 21. In the slave station 21, the optical/electrical conversion part 15 performs optical/electrical conversion of the input optical signal. By frequency-separating the output signal of the optical/electrical conversion part 15 (a separation part therefor is not illustrated), the RF signal and the code division multiple access signal are obtained. From the slave station 21, the RF signal and the code division multiple access signal obtained in the aforementioned manner are sent through the antenna 21a toward each mobile terminal in the talking area of the slave station 21.
FIG. 8 is a block diagram showing an exemplary structure of the radio base station of FIG. 2 to which the optical transmission system of FIG. 7 is applied. FIG. 8 shows elements necessary when transmitting a signal from the slave station 21 to the master station 20. Referring to FIG. 8. the slave station 21 comprising the antenna 21a is provided with the separation part 60, the amplification parts 61 and 62, the electrical/optical conversion parts 63 and 64 and the wavelength division multiplexing part 65 of FIG. 7, and the master station 20 is provided with the wavelength division demultiplexing part 66 and the optical/electrical conversion parts 67 and 68.
In a talking area of the slave station 21, a mobile terminal for the current system and a mobile terminal for the CDMA system are mixedly provided (not shown). From these mobile terminal ends, an RF signal and a code division multiple access signal are sent toward the slave station 21. In the slave station 21, these RF signal and code division multiple access signal are received by the antenna 21a and inputted in the separation part 60. The separation part 60 separates the input signal including the RF signal and the code division multiple access signal into the RF signal and the code division multiple access signal.
FIG. 9 is a block diagram showing another exemplary structure of the radio base station of FIG. 2 to which the optical transmission system of FIG. 7 is applied. FIG. 9 shows elements necessary when transmitting a signal from the master station 20 to the slave station 21. Referring to FIG. 9, the slave station 21 comprising a pair of antennas 21a is provided with the wavelength division demultiplexing part 66 and the optical/electrical conversion parts 67 and 68 of FIG. 7, and the master station 20 is provided with the separation part 60, the amplification parts 61 and 62, the electrical/optical conversion parts 63 and 64 and the wavelength division multiplexing part 65.
The optical signal outputted from the master station 20 as in the aforementioned manner propagates in the optical fiber 22 and reaches the slave station 21. In the slave station 21, the wavelength division demultiplexing part 66 separates the optical signal from the master station 20 into an optical signal corresponding to the RF signal and an optical signal corresponding to the code division multiple access signal. The optical signal corresponding to the RF signal is subjected to optical/electrical conversion in the optical/electrical conversion part 67. The optical signal corresponding to the code division multiple access signal is subjected to optical/electrical conversion in the optical/electrical conversion part 68. Thus, the RF signal and the code division multiple access signal are obtained. From the slave station 21, the RF signal and the code division multiple access signal obtained in the aforementioned manner are sent through the pair of antennas 21a toward each mobile terminal in the talking area of the slave station 21.
The slave station 130 comprises an optical/electrical conversion part 131, an electrical/optical conversion part 133, a first amplification part 132, a second amplification part 134a, a third amplification part 134b, a first circulator 135a, a second circulator 135b, a combiner 137, a first antenna 136a and a second antenna 136b.
The second amplification part 134a, the first circulator 135a and the first antenna 136 process a signal with a first frequency band (a frequency band utilized in conventional radio communication service). This signal with the first frequency band is not subjected to power control when sent from a first mobile terminal.
On the other hand, the third amplification part 134b, the second circulator 135b and the second antenna 136b process a signal with a second frequency band (a frequency band utilized for performing new radio communication service). This signal with the second frequency band is subjected to power control when sent from a second mobile terminal. This second frequency band may be simply different from the first frequency band, and there is no particular restriction in allocation.
FIG. 11 shows exemplary relation between the frequencies and received power of the signals received by the first antenna 136a and the second antenna 136b.
An optical signal sent from the master station 110 is transmitted through the optical fiber 121 to the slave station 130 present on a remote site. In the slave station 130, the optical/electrical conversion part 131 receives the optical signal sent from the master station 110 and converts the same to a radio modulation signal which is an electric signal. The first amplification part 132 amplifies and outputs this radio modulation signal. The amplified radio modulation signal is radiated through the circulator 135a from the antenna 136a if this is a radio modulation signal with the first frequency band (hereinafter referred to as a first radio modulation signal), or radiated through the circulator 135b from the antenna 136b if this is a radio modulation signal with the second frequency band (hereinafter referred to as a second radio modulation signal). The first and second radio modulation signals radiated from the antennas 136a and 136b are received by corresponding first and second mobile terminals (not shown) in the area respectively.
The first radio modulation signal sent from each first mobile terminal in the area is received by the first antenna 136a and thereafter frequency-multiplexed. As hereinabove described, the first radio modulation signal is not subjected to power control when sent from the first mobile terminal, and hence dispersion takes place in the received power due to the difference in distance between each first mobile terminal and the slave station 130.
The frequency-multiplexed first radio modulation signal is inputted through the circulator 135a in the second amplification part 134a. The second amplification part 134a amplifies the inputted first radio modulation signal and outputs the same to the combiner 137.
On the other hand, the second radio modulation signal sent from each second mobile terminal in the area is received by the second antenna 136b and thereafter frequency-multiplexed. As hereinabove described, the second radio modulation signal is subjected to power control when sent from the second mobile terminal, and hence the received power in the slave station 130 reaches a constant level without depending on the difference in distance between each second mobile terminal and the slave station 130.
The frequency-multiplexed second radio modulation signal is inputted through the circulator 135b in the third amplification part 134b. The third amplification part 134b amplifies the inputted second radio modulation signal and outputs the same to the combiner 137. At this time, the third amplification part 134b performs amplification so that the level of the amplified second radio modulation signal becomes smaller than the level of the first radio modulation signal after amplification by the second amplification part 134a.
The combiner 137 multiplexes the first radio modulation signal outputted from the second amplification part 134a and the second radio modulation signal outputted from the third amplification part 134b and outputs the same to the electrical/optical conversion part 133. The electrical/optical conversion part 133 receives the multiplexed radio modulation signal, converts the same to an optical signal and outputs the same. The optical signal outputted after converted in this electrical/optical conversion part 133 is transmitted through the optical fiber 122 to the master station 110 present on a remote site.
Assuming that the carrier number N is "8" which is the number of mobile terminals capable of simultaneous talking from places close to the slave station 300 in the conventional radio signal transmitter, calculation of the distortion characteristic in the case of newly frequency-multiplexing a signal with the second frequency band this time is performed. FIG. 12 shows the calculation result.
A radio signal transmitter for transmitting a signal including both of a radio signal being in a first frequency band and not subjected to transmission power limitation (hereinafter referred to as a first radio signal) and a radio signal being in a second frequency band different from the first frequency band and subjected to transmission power limitation (hereinafter referred to as a second radio signal), comprising
at a sending end:
a separation part (10) separating said signal into the first radio signal and the second radio signal;
a first amplification part (11) amplifying said first radio signal with an amplification factor related to the power of the first radio signal;
a second amplification part (12) amplifying said second radio signal with an amplification factor related to the power of the second radio signal; and
a combination part (13) combining amplified said first radio signal and amplified said second radio signal.
The radio signal transmitter in accordance with claim 1, further comprising at the sending end an electrical/optical conversion part (14) performing electrical/optical conversion of an output signal of said combination part (13), and
comprising at a receiving end an optical/electrical conversion part (15) performing optical/electrical conversion of an output optical signal of said electrical/optical conversion part (14), wherein
the sending end and the receiving end are connected to each other by an optical fiber (22).
The radio signal transmitter in accordance with claim 1, wherein said second radio signal is a signal subjected to code division multiple access.
The radio signal transmitter in accordance with claim 3, further comprising at the sending end an electrical/optical conversion part (14) performing electrical/optical conversion of an output signal from said combination part (13), and
The radio signal transmitter in accordance with claim 4, wherein said first amplification part (11) and said second amplification part (12) respectively further perform amplification with such amplification factors that the strength of an input optical signal in said optical/electrical conversion part (15) will not exceed the upper limit of a linear region of the optical/electrical conversion part (15).
The radio signal transmitter in accordance with claim 5, wherein said optical/electrical conversion part (15) is formed by an optical/electrical conversion device (30) and an amplifier (31) previously amplifying an output signal of the optical/electrical conversion device (30).
The radio signal transmitter in accordance with claim 4, wherein said first amplification part (11) and said second amplification part (12) respectively further perform amplification with such amplification factors that the power of an input signal in said electrical/optical conversion part (14) will not exceed the upper limit of a linear region of the electrical/optical conversion part (14).
The radio signal transmitter in accordance with claim 7, wherein said first amplification part (11) and said second amplification part (12) respectively further perform amplification with such amplification factors that the strength of an input optical signal in said optical/electrical conversion part (15) will not exceed the upper limit of a linear region of the optical/electrical conversion part (15).
The radio signal transmitter in accordance with claim 8, wherein said optical/electrical conversion part (15) is formed by an optical/electrical conversion device (30) and an amplifier (31) previously amplifying an output signal of the optical/electrical conversion device (30).
A radio signal transmitter for transmitting a signal including both of a radio signal being in a first frequency band and not subjected to transmission power limitation (hereinafter referred to as a first radio signal) and a radio signal being in a second frequency band different from the first frequency band and subjected to transmission power limitation (hereinafter referred to as a second radio signal), wherein
a sending end and a receiving end are connected to each other by an optical fiber (22), said radio signal transmitter comprising
a separation part (60) separating said signal into said first radio signal and said second radio signal;
a first amplification part (61) amplifying said first radio signal with an amplification factor related to the power of the first radio signal;
a second amplification part (62) amplifying said second radio signal with an amplification factor related to the power of the second radio signal;
a first electrical/optical conversion part (63) performing electrical/optical conversion of amplified said first radio signal;
a second electrical/optical conversion part (64) performing electrical/optical conversion of amplified said second radio signal; and
a wavelength division multiplexing part (65) wavelength-division-multiplexing a first optical signal obtained by conversion through said first electrical/optical conversion part (63) and a second optical signal obtained by conversion through said second electrical/optical conversion part (64), and comprising
a wavelength division demultiplexing part (66) wavelength-separating an output optical signal of said wavelength division multiplexing part (65) into said first optical signal and said second optical signal;
a first optical/electrical conversion part (67) performing optical/electrical conversion of said first optical signal; and
a second optical/electrical conversion part (68) performing optical/electrical conversion of said second optical signal.
The radio signal transmitter in accordance with claim 10, wherein said second radio signal is a signal subjected to code division multiple access.
The radio signal transmitter in accordance with claim 11, wherein said first amplification part (61) further performs amplification with such an amplification factor that the strength of an input optical signal in said first optical/electrical conversion part (67) will not exceed the upper limit of a linear region of the first optical/electrical conversion part (67), and
said second amplification part (62) further performs amplification with such an amplification factor that the strength of an input optical signal in said second optical/electrical conversion part (68) will not exceed the upper limit of a linear region of the second optical/electrical conversion part (68).
The radio signal transmitter in accordance with claim 12, wherein said first optical/electrical conversion part (67) and said second optical/electrical conversion part (68) are respectively formed by optical/electrical conversion devices (30) and amplifiers (31) previously amplifying output signals of the optical/electrical conversion devices (30).
The radio signal transmitter in accordance with claim 11, wherein said first amplification part (61) further performs amplification with such an amplification factor that the power of an input signal in said first electrical/optical conversion part (63) will not exceed the upper limit of a linear region of the first electrical/optical conversion part (63), and
said second amplification part (62) further performs amplification with such an amplification factor that the power of an input signal in said second electrical/optical conversion part (64) will not exceed the upper limit of a linear region of the second electrical/optical conversion part (64).
The radio signal transmitter in accordance with claim 14, wherein said first amplification part (61) further performs amplification with such an amplification factor that the strength of an input optical signal in said first optical/electrical conversion part (67) will not exceed the upper limit of a linear region of the first optical/electrical conversion part (67), and
The radio signal transmitter in accordance with claim 15, wherein said first optical/electrical conversion part (67) and said second optical/electrical conversion part (68) are respectively formed by optical/electrical conversion devices (30) and amplifiers (31) previously amplifying output signals of the optical/electrical conversion devices (30).
A radio signal transmitter for transmitting both of a radio signal being in a first frequency band and not subjected to transmission power limitation (hereinafter referred to as a first radio signal) and a radio signal being in a second frequency band different from the first frequency band and subjected to transmission power limitation (hereinafter referred to as a second radio signal), comprising
A radio signal transmitter for transmitting both of a radio signal being in a first frequency band and not subjected to transmission power limitation (hereinafter referred to as a first radio signal) and a radio signal being in a second frequency band different from the first frequency band and subjected to transmission power limitation (hereinafter referred to as a second radio signal), wherein
EP19990111994 1998-10-06 1999-06-29 Radio signal transmitter in two frequency bands with and without power limitation Expired - Fee Related EP0993124B1 (en)
JP28431098 1998-10-06
JP28431098A JP4063419B2 (en) 1998-10-06 1998-10-06 Optical transmission system
EP0993124A2 true true EP0993124A2 (en) 2000-04-12
EP0993124A3 true EP0993124A3 (en) 2003-04-02
EP0993124B1 EP0993124B1 (en) 2008-04-16
ID=17676895
EP19990111994 Expired - Fee Related EP0993124B1 (en) 1998-10-06 1999-06-29 Radio signal transmitter in two frequency bands with and without power limitation
US (1) US6292673B1 (en)
EP (1) EP0993124B1 (en)
JP (1) JP4063419B2 (en)
CN (2) CN1291560C (en)
DE (1) DE69938528D1 (en)
WO2003003637A2 (en) * 2001-06-29 2003-01-09 Hrl Laboratories, Llc Method, system, and apparatus for wireless wavelength division multiplexing
US10009094B2 (en) 2017-05-09 2018-06-26 Corning Optical Communications Wireless Ltd Optimizing remote antenna unit performance using an alternative data channel
EP0762674A2 (en) * 1995-09-08 1997-03-12 Siemens Aktiengesellschaft Method and circuit to transmit received signals from an antenna to a base station of a radio system
JPH0670362A (en) 1992-08-19 1994-03-11 Matsushita Electric Ind Co Ltd Optical transmitter for radio base station
WO2003003637A3 (en) * 2001-06-29 2003-09-18 Hrl Lab Llc Method, system, and apparatus for wireless wavelength division multiplexing
JP4063419B2 (en) 2008-03-19 grant
CN1510852A (en) 2004-07-07 application
JP2000115837A (en) 2000-04-21 application
US6292673B1 (en) 2001-09-18 grant
DE69938528D1 (en) 2008-05-29 grant
CN1250325A (en) 2000-04-12 application
CN1140145C (en) 2004-02-25 grant
CN1291560C (en) 2006-12-20 grant
EP0993124B1 (en) 2008-04-16 grant
EP0993124A3 (en) 2003-04-02 application
Ipc: 7H 04B 1/04 A
Inventor name: SASAI, HIROYUKI
Inventor name: MASUDA, KOUCHI
Inventor name: MAEDA, KAZUKI
Inventor name: MORIKURA, SUSUMU
Ref document number: 69938528