Abstract:
Disclosed is an RoF system providing an HD wireless communication service. The RoF system includes the base station for transmitting and receiving each of the TDD/FDD individual signals and TDD/FDD combined signals, channel-combining downstream signals for a TDD scheme with downstream signals for an FDD scheme, and generating TDD/FDD mode control signals; a base station donor for receiving downstream RF signals from the base station, converting the resultant signals into downstream optical signals, outputting the converted signals, and delivering upstream optical signals, which are input to the remote station from the wireless terminals, to the base station; and the remote station for switching a corresponding duplexing mode operation according to wireless service channel states of the wireless terminals, converting the downstream optical signals transmitted from the base station donor into service RF signals, amplifying the converted service RF signals, and providing the amplified service RF signals to the wireless terminals through antennas.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) AND CLAIM OF PRIORITY 
     The present application claims the benefit under 35 U.S.C. §119(a) of an application entitled “RoF System Providing HD Wireless Communication Service and Signal Control Method for the same” filed in the Korean Industrial Property Office on Mar. 6, 2007 and assigned Serial No. 2007-22110, the contents of which are hereby incorporated by reference. 
     TECHNICAL FIELD OF THE INVENTION 
     The present application relates generally to a wireless communication system, and more particularly to a communication system that improves flexibility of resource assignment and maximizes system performance by a Radio over Fiber (RoF) system, and that accepts a wireless communication service of a Hybrid Duplexing (HD) scheme for either individually applying a Time Division Duplexing (TDD) transmission scheme and a Frequency Division Duplexing (FDD) transmission scheme or applying a combined transmission scheme thereof according to positions of wireless terminals. 
     BACKGROUND OF THE INVENTION 
     With the development of the wireless communication industry, various wireless communication schemes have been proposed. In addition to the existing mobile communication network supporting a specific wireless communication scheme, it is possible to implement a mobile communication network supporting a wireless communication scheme different from the existing wireless communication scheme. 
     Therefore, the advent of a wireless environment, which includes the mixed mobile communication networks supporting different wireless communication schemes between them, is expected. 
     In such a wireless environment, it is necessary for mobile users to select and use a proper wireless communication scheme according to a wireless condition. 
     In line with this, a 3rd generation wireless communication system has been developed to perform high-speed and large capacity data communication as well as existing voice communication. 
     The 3rd generation wireless communication systems can be divided into systems of two standardization organizations, which include a 3rd Generation Partnership Project (3GPP), which is a European asynchronous standardization organization, and a 3rd Generation Partnership Project 2 (3GPP2), which is a synchronous standardization organization of the US. A typical scheme which is being discussed in the 3GPP organization is a Wideband Code Division Multiple Access (hereinafter, referred to as WCDMA) scheme, and a typical scheme which is being discussed in the 3GPP2 organization is a Code Division Multiple Access (hereinafter, referred to as CDMA) scheme. 
     The WCDMA scheme can be reclassified into WCDMA using the FDD scheme and WDCMA using the TDD scheme. 
       FIG. 1  is a block diagram illustrating a wire relay system of a conventional FDD wireless communication service system according to one embodiment. Referring to  FIG. 1 , the FDD is a scheme in which transmission and reception for communication are performed based on divided frequencies. First, RF downstream signals modulated in an FDD modem  2  of a Base Station (BS)  1  are converted into optical signals in a base station donor  3 , and then the converted signals are delivered to the Remote Station (RS)  15  via an optical fiber by an optical transmitter  4 . The downstream optical signals received from the base station donor  3  are input to a downstream RF signal conversion/amplification unit  11  by an optical receiver  10 , and the input signals are delivered to wireless terminals via a duplexer  14  and an antenna  17 . 
     Then, an FDD wireless communication service is performed. Upstream signals generated by the wireless terminals are input to a duplexer  14  of the RS  15  through an antenna  17  for frequency division. Then, the frequency-divided signals are amplified in a downstream RF signal reception/amplification unit  13 , the amplified signals are input to the optical receiver  6  of the base station donor  3  via an optical receiver  12  and an optical fiber, and the resultant signals are input to the FDD modem  2  of the BS  1 . 
       FIG. 2  is a block diagram illustrating a wire relay system of a conventional TDD wireless communication service system according to one embodiment. As shown in  FIG. 2 , the TDD is a scheme in which transmission and reception are divided according to different times and communication is performed. First, RF downstream signals modulated in a TDD modem  22  of a BS  21  are delivered to an optical transmitter  28  of a base station donor  23 , and TDD sync signals from the TDD modem  22  are delivered to a TDD switching control transmitter  26  of the base station donor via a modem controller  24 . 
     The TDD switching control transmitter  26  generates TDD switching control signals for switching the TDD sync signals at predetermined time, and the TDD switching control signals are converted into downstream optical signals, and the resultant signals are transmitted to the RS  25  through an optical transmitter  27 . The optical receiver  32  of the RS  25  receives the downstream optical signals, the resultant signals are output by a TDD switching control signal distributor  33 , and switching is performed according to the TDD switching control signals at corresponding times. Then, the TDD transmission scheme downstream signals received in an optical receiver  37  of the RS  25  are converted into RF signals, and the resultant signals are amplified. Therefore, the TDD transmission scheme service is provided to the wireless terminals through the antenna  39 . In this case, for each wireless terminal receiving the provided TDD transmission scheme service, the times for downlink and uplink transmission and reception have been predetermined. 
     Accordingly, the wireless terminals and the BS perform communication within the predetermined times. In this case, the BS may assign some or all of the available time slots to wireless terminals performing communication. 
     As such, according to the FDD transmission scheme, frequencies for downlink and uplink transmission and reception between the BS and the wireless terminals are individually set, and the communication between wireless terminals and a BS is performed based on the set frequencies at all time. 
     Accordingly, an FDD scheme is suitable for use of macro-cell because it does not have a round-trip delay problem. The FDD scheme can provide a service suitable for a rapidly moving terminal due to a large cell radius. 
     On the other hand, in the FDD scheme, frequency bandwidths are symmetrical and are fixedly allocated. Therefore, the FDD scheme is limited in providing a variable asymmetric service. 
     Further, according to the TDD scheme, different time slots are assigned to uplink and downlink established between a BS and a specific wireless terminal. Therefore, the TDD scheme is suitable for provision of an asymmetric service. However, in the TDD scheme, when a cell radius becomes large, a guard time between transmission and reception increases due to the round-trip delay and thus transmission efficiency is reduced. 
     Therefore, the TDD scheme is not suitable for a cell with a large radius, such as a macro-cell, and each cell does not have an identical asymmetry rate under the multiple cell environments in the TDD scheme. Therefore, in the TDD scheme, the same frequency interference increases between terminals located in edges of adjacent cells. 
     Accordingly, a next generation wireless communication service requires a high-speed data rate to be provided to rapidly moving terminals, so that it is necessary to research a system utilizing the advantages of TDD and FDD scheme. 
     SUMMARY OF THE INVENTION 
     To address the above-discussed deficiencies of the prior art, it is a primary object to provide an RoF system providing an HD wireless communication service and a signal control method for the same in a wireless mobile communication system, by which it is possible to perform a wire relay of a wireless communication system capable of employing all required duplexing transmission schemes according to the channel state of a wireless service. 
     In one embodiment, a wireless network is disclosed for providing hybrid duplexing wireless service. The wireless network comprises a plurality of base station, wherein each of the base stations communicates with each of a plurality of wireless terminals using a selected one of: i) a time division duplexing (TDD) service; ii) a frequency division duplexing (FDD) service; and iii) a TDD/FDD combined service. Advantageously, the each base station selects the selected one of the TDD service, the FDD service and the TDD/FDD combined service to communicate with a first one of the plurality of wireless terminals according to a state of a wireless channel associated with the first wireless terminal. 
     In accordance with an aspect of the present invention, there is provided an RoF system for providing an HD wireless communication service in a wire/wireless communication system including a Base Station (BS) capable of establishing communication with wireless terminals and a Remote Station (RS) connected to the BS through an optical fiber, wherein the BS can provide a Time Division Duplexing (TDD) service and a Frequency Division Duplexing (FDD) service according to wireless service channel states of the wireless terminals, the RoF system including: the BS for transmitting and receiving each of the TDD/FDD individual signals and TDD/FDD combined signals, channel-combining downstream signals for a TDD scheme with downstream signals for an FDD scheme, and generating TDD/FDD mode control signals; a base station donor for receiving downstream RF signals from the BS, converting the resultant signals into downstream optical signals, outputting the converted signals, and delivering upstream optical signals, which are input to the RS from the wireless terminals, to the BS; and the RS for switching a corresponding duplexing mode operation according to wireless service channel states of the wireless terminals, converting the downstream optical signals transmitted from the base station donor into service RF signals, amplifying the converted service RF signals, and providing the amplified service RF signals to the wireless terminals through antennas. 
     In accordance with another aspect of the present invention, there is a signal transmission control method in a wire/wireless communication system including a BS capable of establishing communication with wireless terminals, a base station donor, and an RS connected to the base station donor through optical fibers, wherein the BS can provide a TDD transmission service and an FDD transmission service according to wireless service channel states of the wireless terminals, the signal transmission control method including the steps of: disconnecting switching of FDD upstream signal paths according to the control of the TDD/FDD mode control signals of the RS, and connecting switching of TDD upstream signal paths according to the control of the TDD switching control signals of the RS, when TDD upstream signals are received from the wireless terminals through an antenna of the RS; and delivering the TDD upstream signals passed through the TDD upstream signal paths to the first base station receiver of the BS via the base station donor and upstream optical links. 
     Before undertaking the DETAILED DESCRIPTION OF THE INVENTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or,” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and the term “controller” means any device, system or part thereof that controls at least one operation, such a device may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts: 
         FIG. 1  is a block diagram illustrating a construction of a wire relay system in an FDD wireless communication service system according to the prior art; 
         FIG. 2  is a block diagram illustrating a construction of a wire relay system in a TDD wireless communication service system according to the prior art; 
         FIG. 3  is a view illustrating an RoF system to which an HD scheme is applied, according to one embodiment of the present invention; 
         FIG. 4  is an exemplary view illustrating a channel construction of an RoF system to which an HD scheme is applied, according to a first embodiment of the present invention; 
         FIG. 5  is a block diagram illustrating a construction of an RoF system operating through an HD scheme according to one embodiment of the present invention; 
         FIG. 6  is a block diagram illustrating a construction of a wireless communication system operating in an HD mode including the combined TDD and FDD mode, according to a first embodiment of the present invention; 
         FIG. 7  is a block diagram illustrating a construction of a wireless communication system operating in a TDD mode, according to a second embodiment of the present invention; 
         FIG. 8  is a block diagram illustrating a construction of a wireless communication system operating in an FDD mode, according to a third embodiment of the present invention; and 
         FIG. 9  is a flow diagram illustrating a signal control method in an RoF system providing an HD wireless communication service according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 4 through 9 , discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged communication network. 
     The present invention provides an RoF system providing a hybrid duplexing (HD) wireless communication service and a signal control method for the same. According to the present invention, a base station can efficiently deal with both a wireless communication service provided according a combined TDD/FDD transmission scheme and a wireless mobile communication service provided according to an individual duplexing scheme. Therefore, it is possible to simplify the construction of the base station and the remote station and to reduce manufacturing cost. 
     In line with this,  FIG. 3  is an exemplary view of a radio-over-fiber (RoF) system to which a hybrid duplexing (HD) scheme is applied, according to a first embodiment of the present invention. As shown in  FIG. 3 , a base station (BS) logically has two cell radiuses  350  and  360 , and a service mobile terminal  104  located relatively nearer to the base station antenna has a good wireless channel state and thus has a high probability to receive a broadband data service. Therefore, the service mobile terminal  104  can receive a service by resource assignment of a TDD link advantageous for such a service. However, in a case of a mobile terminal  310  located within a cell  360  relatively far from the base station antenna, it is advantageous to receive a service through FDD links because the round-trip time delay problem occurs much less. That is, it can be said that a broadband TDD mode is relatively advantageous to the mobile terminal  104  relatively nearer to the base station antenna, whereas a narrowband FDD mode is advantageous to the mobile terminal  310  located in a place relatively farther from the base station antenna. However, in a remote station (RS)  340  connected to the base station (BS) by an optical fiber link, a mobile terminal  320 , located within a distance in which wireless service signals can be transmitted and received through an antenna of the remote station  340 , is in need of HD link connection including the combined TDD and FDD transmission schemes, as well as connection through duplexing link using either a TDD transmission scheme or an FDD transmission scheme. 
       FIG. 4  is an exemplary view illustrating a channel construction of an improved hybrid duplexing (HD) system, according to the present invention. In the present invention, all system frequency resources are divided into two frequency bandwidths, so that the two divided frequency bandwidths can used as channels having different duplexing characters. 
     As shown in  FIG. 4 , given frequency resources are divided into two TDD channels providing uplink and downlink and one FDD channel providing only uplink. 
       FIG. 5  is a block diagram illustrating a construction of an HD wireless communication system according to one embodiment of the present invention. Referring to  FIG. 5 , the wireless communication system according to one embodiment of the present invention includes a BS  50 , a base station donor  53 , upstream/downstream optical links  57  and  66 , and an RS  55 . 
     The BS  50  includes a TDD/FDD modem  51  and a TDD/FDD modem controller  69 . Herein, the TDD/FDD modem  51  modulates and demodulates each of TDD downstream RF signals, FDD downstream RF signals, and HD downstream RF signals, and it channel-combines downstream signals for TDD scheme with downstream signals for FDD scheme. Herein, the TDD/FDD modem controller  69  controls a TDD/FDD mode signal operation by using signals output from the TDD/FDD modem  51 . Herein, mode control signals of the TDD/FDD downstream signals correspond to mode control signals of a TDD transmission scheme, mode control signals of an FDD transmission scheme, or mode control signals of an HD transmission scheme, the HD transmission scheme resulting from combination of the TDD and FDD transmission schemes. 
     The base station donor  53  includes a TDD/FDD mode control signal unit  54 , a TDD switching control signal unit  52 , a TDD/FDD downstream transmitter  57 , a combiner  56 , a TDD upstream receiver  67 , and an FDD upstream receiver  68 . Herein, the TDD/FDD mode control signal unit  54  receives downstream RF signals transmitted from the BS  50  and outputs TDD/FDD mode control signals for setting a TDD/FDD mode. Herein, the TDD switching control signal unit  52  outputs TDD switching control signals for switching the TDD sync signals from among downstream RF signals transmitted from the BS  50 . Herein, the TDD/FDD downstream transmitter  57  converts RF signals corresponding to one of TDD/FDD downstream signals mode control signals, transmitted from the BS  50 , into optical signals, and then outputs the resultant signals, the TDD/FDD downstream signals mode control signals including mode control signals of a TDD transmission scheme, mode control signals of an FDD transmission scheme, and mode control signals of a HD transmission scheme. Herein, the combiner  56  multiplexes and outputs signals output from each of the TDD/FDD mode control signal unit  54 , the TDD switching control signal unit  52 , and the TDD/FDD downstream transmitter  57 . Herein, the TDD upstream receiver  67  and the FDD upstream receiver  68  deliver the upstream signals received from the RS to the BS. 
     The RS  55  includes a distributor  58 , a TDD/FDD control signal reception/distribution unit  59 , a TDD/FDD downstream signal amplifier  60 , a filter  61 , switching units  62  and  63 , a TDD upstream signal reception/amplification unit  64 , an FDD upstream signal reception/amplification unit  70 , and a distributor  65 . Herein, the distributor  58  receives TDD/FDD mode control signals and TDD/FDD downstream signals, received from the base station donor  53  through the TDD/FDD downstream optical links, and then distributes the received signals to respective paths. Herein, the TDD/FDD control signal reception/distribution unit  59  switches the TDD/FDD mode control signals, received from the distributor  58 , according to the set mode, and the TDD/FDD control signal reception/distribution unit  59  divides the resultant signals according to frequencies with different bandwidths and delivers the divided signals to the antenna. Herein, the TDD/FDD downstream signal amplifier  60  amplifies the TDD/FDD downstream signals received from the distributor  58 , and the filter  61  separates each of the TDD/FDD upstream signals, which are received from the antenna, according to a corresponding path. Herein, the switching units  62  and  63  control switching according to the mode, and the TDD upstream signal reception/amplification unit  64  and the FDD upstream signal reception/amplification unit  70  are controlled by the switching units  62  and  63 . Herein, the distributor  65  combines upstream signals delivered from each of the TDD upstream signal reception/amplification unit  64  and the FDD upstream signal reception/amplification unit  70 , and then delivers the resultant signals to the TDD/FDD upstream optical links. 
       FIG. 6  is a block diagram illustrating a construction of a wireless communication system operating in an HD mode including the combined TDD and FDD mode, according to a first embodiment of the present invention. Referring to  FIG. 6 , when upstream RF signals received from the wireless terminals through an antenna  621  of the RS  645  correspond to an HD mode upstream signals, the TDD upstream signals are input to a switching unit  622  through an RF duplexer # 1   620  after direction-adjustment of a circulator  619 . The switching unit  622  is connected to a corresponding path of the TDD upstream signals according to the control of the TDD switching control signal unit  629 , and the resultant signals are input to a Low Noise Amplifier (LNA)  623  for low noise-amplification. The FDD upstream signals are also input to an LNA  626  through the RF duplexer # 1   620  for low noise-amplification, and the resultant signals are switched according to the control of the TDD/FDD mode control signal unit  628 . 
     Then, each of the low-noise amplified TDD/FDD signals is mixed in a duplexer # 2   624 , and the mixed signals are upwardly delivered to the base station donor  640  by an upstream optical transmitter  625 . The TDD/FDD upstream signals received from the RS  645  through the upstream optical link are input to the upstream optical receiver  614 . Since the TDD/FDD upstream RF signals have different frequency bandwidths, each of the TDD/FDD upstream RF signals is divided according to frequencies by the duplexer  612 , and the divided signals are delivered to the BS  600  through a first upstream RF receiver and a second upstream RF receiver. 
     Meanwhile, the TDD RF upstream signals and the FDD RF upstream signals received to the first and second base station receivers  661  and  662  from the base station donor  640  are input to the TDD/FDD modem  601  of the BS  600 . 
     The signals are delivered to the TDD/FDD mode control signal unit  603  of the base station donor  640  through the TDD/FDD modem controller  602 , and mode control signals of an HD transmission scheme are generated. In addition, the TDD switching control signal unit  604  outputs TDD switching control signals for switching the TDD sync signals at predetermined times, according to the generated HD mode. Then, downstream signals output from the TDD/FDD mode control signal unit  603  and the TDD switching control signal unit  604  are combined and transmitted to the downstream optical transmitter  606 . Then, the TDD/FDD downstream RF signals, modulated and channel-combined by the TDD/FDD modem  601  of the BS  600 , are received in the downstream optical transmitter  613  through the downstream RF transmitter  611 . The received downstream RF signals together with downstream signals output from the TDD/FDD mode control signal unit  603  and the TDD switching control signal unit  604 , are transmitted to the RS  645 . The HD downstream signals delivered to the RS  645  are low noise-amplified by the LNA  617  and are high power-amplified by the High Power Amplifier (HPA)  618 . Therefore, the HD service including the TDD and FDD services is provided to wireless terminals via the RF duplexer # 1   620  and the antenna  621 . 
       FIG. 7  is a block diagram illustrating a construction of a wireless communication system operating in a TDD mode, according to a second embodiment of the present invention. Referring to  FIG. 7 , in a case where upstream signals received from wireless terminals through an antenna  721  of the RS  745  are TDD mode upstream signals, when the TDD upstream signals are input to a switching unit  722  through an RF duplexer # 1   720  after the direction-adjustment of the circulator  719 , the switching unit  722  is connected to a corresponding path of the TDD upstream signals according to the control of the TDD switching control signal unit  729 . Then, the resultant signals are input to an LNA # 1   723 , so that weak signals are low noise-amplified. In this case, the switching of the FDD upstream signal path is grounded by an RF terminator. 
     Moreover, the low noise-amplified TDD upstream signals are input to the base station donor  740  via a duplexer # 2   724  and an upstream optical transmitter  725 . The TDD upstream signals received from the RS  745  through an upstream optical link are input to an upstream optical receiver  714 , and are delivered to the first base station receiver  761  from the duplexer  712  through the first upstream RF receiver. 
     Meanwhile, TDD/FDD mode control signals are delivered to a TDD/FDD mode control signal unit  703  of the base station donor  740  by a TDD/FDD modem controller  702 . 
     Moreover, the TDD switching control signal unit  704  outputs a TDD switching control signal for performing the switching at predetermined times depending on the TDD sync signals. Then, downstream signals output from the TDD/FDD mode control signal unit  703  and the TDD switching control signal unit  704  are combined, and are transmitted to the RS  745  through a downstream optical transmitter  706 . The TDD/FDD downstream RF signals modulated and channel-combined by the TDD/FDD modem  701  of the BS  700  are generated in a base station transmitter, and are input to a downstream optical transmitter  713  thorough a downstream RF transmitter  711 . Then, the resultant signals together with the multiplexed downstream signals output from the TDD/FDD mode control signal unit  703  and the TDD switching control unit  704 , are transmitted to the RS  745 . The TDD downstream signals delivered to the RS  745  are low noise-amplified by an LNA  717 , and are high power-amplified by an HPA  718 . Therefore, the TDD transmission service is provided to wireless terminals through the RF duplexer # 1   720  and the antenna  721 . 
       FIG. 8  is a block diagram illustrating a construction of a wireless communication system operating in an FDD mode, according to a third embodiment of the present invention. Referring to  FIG. 8 , when upstream signals received from wireless terminals through an antenna  821  of the RS  845  are FDD mode upstream signals, the FDD upstream signals are low-noise amplified by an LNA # 2   826  through an RF duplexer # 1   820 , and the resultant signals are connected to the second duplexer  824  according to the control of the TDD/FDD mode control signal unit  828 . In this case, a first RF switch  822  of a TDD upstream signal path is grounded by an RF terminator under the control of the TDD switching control signal unit  829 . 
     Then, the FDD upstream signals are delivered to the base station donor  840  via an RF duplexer # 2   824  and an upstream optical transmitter  825 . The FDD upstream signals received from the RS  845  through an upstream optical link are input to an upstream optical receiver  814 , and are divided according to frequencies by the duplexer  812 . Then, the divided signals are delivered to a second base station receiver  862  of the base station  800  through an FDD RF upstream signal unit  2 . 
     Meanwhile, TDD/FDD mode control signals are delivered to the TDD/FDD mode control signal unit  803  of the base station donor  840  from the TDD/FDD modem controller  802 . 
     Moreover, in order to control the RF switch within the RS  845  according to the generated FDD operation mode, the TDD switching control signal unit  804  outputs the TDD switching signals for switching the TDD sync signals at predetermined times. The downstream signals output from the TDD/FDD mode control signal unit  803  and the TDD switching control signal unit  804  are multiplexed, and then transmitted to the downstream optical transmitter  806 . The FDD downstream RF signals modulated and channel-combined by the TDD/FDD modem  801  of the BS  800  are input to downstream optical transmitter  813  through the base station transmitter and the downstream RF transmitter  811 . The input signals together with the multiplexed downstream signals, output from the TDD/FDD mode control signal unit  803  and the TDD switching control signal unit  804 , are transmitted to the RS  845 . The FDD mode downstream signals delivered to the RS  845  are low noise-amplified by the LNA  817  and are high power-amplified by an HPA  818 . Therefore, the FDD transmission service is provided to wireless terminals through an RF duplexer  820  and an antenna  821 . 
       FIG. 9  is a flow diagram illustrating a signal control method in a radio-over-fiber (RoF) system providing an HD wireless communication service according to the present invention. In the signal control method of an HD RoF system providing a wireless communication service according to the present invention, the RoF system includes a BS and an RS capable of establishing communication with wireless terminals. In the wire/wireless communication method, the BS can provide an individual scheme of a TDD transmission scheme and an FDD transmission scheme or a combined HD transmission scheme thereof according to positions and states of wireless terminals, wherein the wire/wireless communication system includes a BS and an RS capable of establishing communication with wireless terminals. First, the RS receives the TDD/FDD mode control signals and the TDD switching control signals from the base station modem controller through the base station donor (step  900 ). 
     When TDD upstream signals are received in the step  900 , the switching of the FDD upstream signal path is disconnected according to the control of the TDD/FDD mode control signal unit  728  (steps  910  and  912 ). The TDD upstream RF signals are connected to the TDD upstream signal path by performing the switching according to the control of the TDD switching control signal unit  729  (step  914 ). Then, the resultant signals are delivered to the BS  700  via the base station donor  740  and an upstream optical link. Therefore, the TDD transmission service is provided to the wireless terminals according to the operation of the TDD/FDD modem of the BS  700  (step  916 ). 
     Moreover, when the FDD upstream signals are received in step  900 , the switching of the FDD upstream signal path is connected according to the control of the TDD/FDD mode control signal unit  828  (step  920 ). The switching of the TDD upstream signal path is disconnected according to the control of the TDD switching control signal unit  829  (step  922 ). Then, the FDD upstream signals are delivered to the BS  800  via the base station donor  840  and an upstream optical link. Therefore, the FDD transmission service is provided to the wireless terminals according to an operation of the TDD/FDD modem of the BS  800  (step  926 ). 
     Furthermore, when the TDD/FDD duplexing mode upstream signals are received in step  900 , the switching of the FDD upstream signal path is connected according to the control of the TDD/FDD mode control signal unit  628  (step  934 ). The switching of the TDD upstream signal path is also connected according to the control of the TDD switching control signal unit  629  (step  932 ). Each of the TDD/FDD upstream signals is delivered to the BS  600  via the base station donor  640  and an upstream optical link. Therefore, the TDD/FDD hybrid mode transmission service is provided to the wireless terminals according to an operation of the TDD/FDD modem  601  and the modem controller  602  within the BS  600  (step  936 ). 
     According to one embodiment of the present invention, it is possible to provide an RoF system capable of providing an HD wireless communication service and achieve a construction and an operation of a signal control method for the same. 
     Although the present disclosure has been described with an exemplary embodiment, various changes and modifications may be suggested to one skilled in the art. It is intented that the present disclosure encompass such changes and modifications as fall within the scope of the appended claims.