Abstract:
A CDMA transmitting and receiving apparatus with multiple applied interface functions and a method thereof is provided. The apparatus is center around a system control unit. The system control unit includes a plurality of interface drivers that works with a base band signal processing unit for converting information of different kinds to a base band signal and then transmits through a communication transceiver. Alternatively, the system control unit also transmits information to at least one of the connecting interfaces when the communication transceiver receives a base band signal. Moreover, the apparatus also provides integration to information of different kinds allowing flexibility and adaptability thereby enabling an efficient and secured use of network management interfaces within a communication system.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention is generally related to a code division multiple access (CDMA) transmitting and receiving apparatus. More particularly, the present invention relates to a CDMA transmitting and receiving apparatus capable of supporting multiple applied interface functions and a method thereof.  
         [0003]     2. Description of the Related Art  
         [0004]     Verse Small Aperture Terminal (VSAT) is a common name for a ground microwave station (or an end terminal) establishing a communication link through a satellite. The VSAT applied satellites currently in use are mostly synchronous satellites and each of the synchronous satellites related to earth is only 1.5 degrees space apart. The VSAT technologies not only involves the ground microwave station and other indoor microwave devices, but also includes signal adjustment coding, link budgets, network management and multiple access. The multiple access technologies are used to provide communication access for multiple users at the same time, and are the basis for more and more technologies.  
         [0005]     The conventional VSAT multiple access includes three types. They are Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA) and Code Division Multiple Access (CDMA). FDMA is the earliest multiple access type of technologies. FDMA divides frequency bands and uses other related technologies for providing more users to communicate. But, FDMA also causes serious problems producing inter-modulation interferences and channel congestions due to the previous frequency overlapping between the C bands and the ground communication system, frequency overlapping of the bandwidths between the synchronized satellites and lacks of flexibility. Although the present FDMA technologies have moved to high frequency bands in Ku or even Ka for a wider bandwidth, but FDMA still faces a lot of challenges as the communication system is becoming more complicated and improved.  
         [0006]     Like FDMA, a conventional TDMA is also a mature multiple access technology. TDMA is mostly used in a VSAT network system. TDMA uses a time slot for a transmission using only one frequency signal for multiple accesses. However, the present TDMA requires a transformation to an adaptive TDMA in order to meet the capacity on demand and the advancement in network software management.  
         [0007]     On the other hand, CDMA uses a code division for providing multiple accesses. In recent years, technologies such as mobile phones, low power wireless phones and satellites have grown rapidly due to the advancement in wireless communication technologies. Moreover, the CDMA technologies are more resisting to a noise compared to other conventional transmission technologies. In addition, the CDMA technologies have the advantages in providing multiple accesses with ease, unaffected by the transmissions nearby and low failing rate. It is not surprising that the CDMA technologies have became more popular in the recent years. Moreover, direct sequence CDMA (DS/CDMA) can handle more data at the same time compared to FDMA and TDMA and is easier to control within a network. As a result, CDMA has also become a mainstream in the ground area communication zone and broad communication coverage zone.  
         [0008]     As previously described, FDMA faces a lot of challenges due to immaturity of the technology as communication continues to grow and advance. On the other hand, adaptive TDMA attempts to meet the capacity on demand inevitably increases the complexity in software network management. In contrast, direct sequence spread spectrum CDMA (DSSS/CDMA) allows higher network capacity compared to FDMA and TDMA and is easier to control within a network. As a result, CDMA has also become a mainstream in the ground area communication zone and broad communication coverage zone.  
         [0009]     At present, CDMA technologies are mainly focused on the principles of the CDMA fundamentals (for example, in the area of spread spectrum communication, spread spectrum coding transmitting and receiving, distribution and apparatus thereof) and application thereof, or implementation on VSAT CDMA systems and MODEM. However, the CDMA technologies and papers have not yet included interfaces for processing input information of different kinds (for example, a fax, a phone, an exchanger and a serial/parallel communication input) and provided an integration in which. Rather, the present CDMA technologies are limited to a user&#39;s only applied interface or simple switching between the radio frequency and the base band signals. In the other words, the present CDMA technologies cannot meet the need of a user today through a VSAT CDMA system. Moreover, the present CDMA technologies cannot provide support for a user and an external protected interface connection simultaneously. Furthermore, the present CDMA technologies do not provide an adequate support for an overall communication network management interface that is safe, secure and efficient.  
       SUMMARY OF THE INVENTION  
       [0010]     The present invention is to provide a CDMA transmitting and receiving apparatus with multiple applied interface functions and a method thereof. The apparatus is able to integrate information inputs of different kinds and provide a more flexible use of the applied interfaces and an expansion thereof.  
         [0011]     Another objective of the present invention is to provide a CDMA transmitting and receiving apparatus with multiple applied interface functions and a method thereof. The apparatus is able to utilize the applied interfaces and system resource usage of an overall communication network, which is safe, secure and efficient.  
         [0012]     In order to achieve the objectives described above, the present invention provides a CDMA transmitting and receiving apparatus with multiple applied interface functions. The apparatus comprises: a base band signal processing unit; a system control unit; a base band transmitter unit; a base band receiver unit and a system processing unit. The base band signal processing unit is capable of converting a variety of analog or digital input data, either in serial or parallel, to a base band data of CDMA. The input data comprises a voicemail, a fax, an exchanger, a network, an external protected device or a common serial/parallel output device. On the other hand, the system processing unit is capable of providing a reference signal according to a plurality of applied parameters of the system control unit. Wherein, the reference signal is programmable to at least one of the base band signal processing unit, the system control unit capable, the base band transmitter and the base band receiver unit.  
         [0013]     The system control unit is capable of setting, changing, monitoring and maintaining a communication link by organizing the base band data according to an outside setting or an internal setting of the apparatus. In addition, the system control unit is capable of integrating a plurality of controllers and a plurality of interface drivers internally and externally to the apparatus.  
         [0014]     The base band transmitter unit is capable of framing a code data according to a setting parameter and outputting a base band analog signal to be ready for a radio frequency communication. In addition, the base band transmitter unit incorporates a function for forward error correction and a function for adjusting the bandwidth (or chip length) for a direct sequence spread spectrum. Thus, the base band transmitter unit provides multiple applied functions for multiple users simultaneously.  
         [0015]     On the other hand, the base band receiver unit is capable of processing and de-framing a base band analog signal from the outside according to the setting parameter and outputting a base band digital signal to the system control unit. In addition, the base band receiver unit incorporates a function for reverse-forward error correction and a function for re-adjusting the bandwidth for a direct sequence spread spectrum.  
         [0016]     As one preferred embodiment of the present invention, the CDMA transmitting and receiving apparatus with multiple applied interface functions further comprises: a radio frequency (RF) transmitter unit and a radio frequency (RF) receiver unit. The radio frequency (RF) transmitter unit is capable of converting the base band analog signal and providing a radio frequency signal for transmitting. The radio frequency transmitter unit is also capable of adjusting a work efficiency of a transmitting signal, setting and selecting a bandwidth within the base band and the radio frequency. In contrast, the radio frequency (RF) receiver unit is capable of receiving the radio frequency signal from the outside and re-converting back to the base band analog signal. In addition, the radio frequency receiver unit is capable of adjusting the gain of the received signal, setting and selecting a bandwidth within the base band and the radio frequency.  
         [0017]     The present invention uses a module for design and implementation. In which, the firmware and software programs are designed according to the need and arrangements of the hardware and state machines. The apparatus can be built by using existing chips or by using VSLI manufacturing to meet System on Chip (SOC).  
         [0018]     The following descriptions describe and illustrate more fully the objectives, characteristics and advantages of the present invention. It is important to note that an element can be directly connected, indirectly connected or coupled to another element, or connected in between the other elements when the element is referred to as being connected or coupled in the description. On the other hand, an element is not connected in between the other elements when the element is referred to as being directly connected or directly coupled.  
         [0019]     It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0020]     The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.  
         [0021]      FIG. 1A  illustrates an overall architecture of a CDMA transmitting and receiving apparatus with multiple applied interface functions.  
         [0022]      FIG. 1B  illustrates a base band transmitter unit, a base band receiver unit, a radio frequency transmitter unit and a radio frequency receiver unit of  FIG. 1A  as one preferred embodiment of the present invention.  
         [0023]      FIG. 1C  illustrates a base band signal processing unit of  FIG. 1A  as another preferred embodiment of the present invention.  
         [0024]      FIG. 2  illustrates an architecture of an interface integration driving unit of  FIG. 1A  as another preferred embodiment of the present invention.  
         [0025]      FIG. 3  illustrates states of a state machine controller of  FIG. 2  as another preferred embodiment of the present invention.  
         [0026]      FIG. 4  shows a flow diagram for a link set state of  FIG. 3  as another preferred embodiment of the present invention.  
         [0027]      FIG. 5  shows an ESC/CSC information frame and an ESC/CSC macro synchronized information frame as another preferred embodiment of the present invention.  
         [0028]      FIG. 6  illustrates a radio frequency CDMA transceiver with multiple functions and a base band CDMA transceiver with multiple functions as another preferred embodiment of the present invention.  
         [0029]      FIG. 7  shows an output spread spectrum (F c =140 MHz, FEC=½, Power≅−10 dbm, F c,cut ≅4.4 MHz, PN length=512) as another preferred embodiment of the present invention.  
         [0030]      FIG. 8  shows an output spread spectrum (F c =140 MHz, FEC=½, Power≅−40 dbm, F c,cut ≅4.4 MHz, PN length=512) as another preferred embodiment of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0031]     The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.  
         [0032]     CDMA uses division of codes for providing a multiple access. CDMA spread spectrum uses orthogonal property for separating CDMA codes. What about CDMA system capacity when CDMA is applied in a real implementation? One method for calculating the CDMA system capacity derived from Gaussian theory is as follow:  
           P   b     ≈     g   ⁡     (   μ   )         =     Q   ⁡     (       [         K   -   1       3   ⁢   N       +       N   0       2   ⁢     E   b           ]       -   0.5       )           
 
         [0033]     As shown from the above formula, the accuracy is very good when the system capacity K (the number of users) is very big. A probability of error P b  is not too big even when the value of K is not big. As a result, the probability of error is small when the chip number (chip)N increases. It is important to note, an error function is Q(x)=0.5erf(x/{square root}{square root over (2)})≈exp(−x 2 /2) /( {square root}{square root over (2π)}x) when x is very big and at this time Q( 3.11)≈10 −3 . Moreover, a simple mathematical formula can be used to estimate CDMA system capacity when the probability of error is 10 −3  and E b /N 0  is big. The formula is as follow:  
       K   &lt;       3   ⁢     N   ⁡     (       1     3.11   2       -     1     2   ⁢       E   b     /     N   0             )         +   1     ≈     N   3         
 
         [0034]     The above formula is used to estimate a system capacity in designing a CDMA system. In the other words, the system can handle N/3 of users when the required probability of error is greater than 10 −3  in a direct sequence spread spectrum. The formula derived from Gaussian, as shown in the above, has been frequently used in a scientific publication due to its simplicity and uniqueness.  
         [0035]     The previous paragraph demonstrates a simple capacity formula for a CDMA system with multiple users. The present invention is related to a CDMA transmitting and receiving apparatus with multiple applied interface functions and a method thereof. In addition, the present invention uses a module for design and implementation. In which, the firmware and software programs are designed according to the need and arrangements of the hardware and state machines, thus making an overall integration with flexibility for the apparatus.  
         [0036]      FIG. 1A  illustrates an overall architecture of a CDMA transmitting and receiving apparatus with multiple applied interface functions.  FIG. 1B  illustrates a base band transmitter unit, a base band receiver unit, a radio frequency transmitter unit and a radio frequency receiver unit of  FIG. 1A  as one preferred embodiment of the present invention.  FIG. 1C  illustrates a base band signal processing unit of  FIG. 1A  as another preferred embodiment of the present invention.  
         [0037]     Referring to  FIG. 1A ,  FIG. 1B  and  FIG. 1C , a base band signal processing unit  130  is capable of converting a variety of analog or digital input data, either in serial or parallel, to a data accepted by a base band transmitter unit  140 . The input data includes a voicemail, a fax, an exchanger, a network, an external protected device or a common serial/parallel output device. The base band signal processing unit  130  is therefore includes two parts: an analog converter and a digital converter. The analog signal interface converter  132  is used in converting a signal from the voicemail, the fax, the exchanger and other analog signals to a specified format of digital data according to a pre-defined set or designed architecture. On the other hand, the serial communication processor  134  is used in converting a data from the network, the external protected device, the common serial/parallel output device (for example, a MUX) or other digital signals also to the specified format of digital data according to the pre-defined set or designed architecture.  
         [0038]     The system control unit  110  is capable of setting, changing, monitoring and maintaining a communication link by organizing the base band data according to an outside setting or an internal setting of the apparatus. In addition, the system control unit is capable of integrating: any interface related driver unit; interface related controllers for an external multiple applied functions base band transceiver; interface related controllers for an external multiple applied functions radio frequency transceiver; an external timing control processor, and a data storage exchange. The system control unit  110  includes a network layer management unit  112 , an interface integration driving unit  114  and a data storage exchange unit  116 . The network layer management unit  112  is capable of setting, changing, monitoring and maintaining the communication link of the interface integration driving unit  114  according to a parameter from an external network management system. The interface integration driving unit  114  is capable of integrating a plurality of interfaces of the apparatus according to an internal setting thereby setting, changing, monitoring and maintaining the communication link. The data storage exchange unit  116  is capable of exchanging parameters of the interfaces of the apparatus, and transmitting and exchanging network information.  
         [0039]      FIG. 2  illustrates an architecture of the interface integration driving unit of  FIG. 1 A  as another preferred embodiment of the present invention. Referring to  FIG. 2 , the interface integration driving unit  114  includes a state machine controller  210  and various kinds of interface drivers  220 ˜ 290 . The state machine controller  210  gathers and integrates information of different kinds from the various interface drivers  220 - 290 . In addition, the state machine controller  210  is capable of setting and controlling the interface drivers  220 - 290  and states thereof, and avoiding an unstable state and a transient state from happening caused by the multiple applied interfaces thereby maintaining an overall system stability. A network layer management driver  220  provides an interface break signal and data-driving capability after a parameter of the external network management system is set. On the other hand, a data storage exchange driver  230  provides another interface break signal and data-driving capability after parameters exchange between any corresponding interfaces, network management information transmission, and information data transmission and exchange. Moreover, an analog signal interface driver  260  provides another interface break signal and also data-driving capability after converting a data from the voicemail, the fax, and the exchanger to the specified format of digital data according to the pre-defined set or designed architecture.  
         [0040]     Furthermore, a protected data interface driver  250  provides another interface break signal for a protected data after receiving (before decoding) or a data before transmission. The protected data interface driver  250  also provides data-driving capability. The protected data or a data before transmission and data-driving capability are done after a data is being converted to the specified format of digital data according to the pre-defined set or designed architecture. Moreover, a data interface driver  240  provides another interface break signal and data-driving capability after converting, for example, a conventional serial or parallel digital data (or with an additional MUX or by using a time division multiplex TDM) to the specified format of digital data according to the pre-defined set or designed architecture. Moreover, a circuit parameter control driver  270  provides another interface break signal and data-driving capability for an interface controller. Moreover, a link efficiency control driver  280  provides another interface break signal and data-driving capability for a transmission efficiency of the base band transmitter unit  140  or the radio frequency transmitter unit  150 . Moreover, a link quality monitor driver  290  provides another interface break signal and data-driving capability for a transmission efficiency of the base band receiver unit  170  or the radio frequency receiver unit  160 .  
         [0041]      FIG. 3  illustrates states of a state machine controller of  FIG. 2  as another preferred embodiment of the present invention. Referring to  FIG. 3 , a solid line represents a change in state during a normal operation. Whereas a dotted line returns a state back to a link set state for a parameter reset when an operation is not operated properly or cannot be maintained. The states are described as follow: 
        A. link ready state S 301 : when the set link state is complete and the link is ready for work.     B. one way link state S 302 : when one party completing a request for the link (the link includes a duplex mode).     C. two ways link state S 303 : when two parties both completing the request for the link (the link includes a duplex mode).     D. normal clear state S 304 : when any party completing an information communication by using the link (the link includes a duplex mode).     E. abnormal clear state S 305 : when the link (the link includes a duplex mode) is terminated before the parties completing the information communication.     F. network set link state S 306 : for setting a format of information processing and an operational parameter according to the external network thereby providing a normal operation for the state machine.     G. receive only state S 307 : for prohibiting any party transmitting, but only receiving from the link.     H. set link state S 308 : for setting a format of information processing, an operational parameter and maintaining a stability; of a link according to a pre-set or a request from the external network.  FIG. 4  shows a flow diagram for the link set state of  FIG. 3  as another preferred embodiment of the present invention. Referring to  FIG. 4 , the flow includes: network management state (by a pre-set or an external network management); information processing modulation selection and setting (including serial and parallel, analog and digital information and network management information selection); protection setting; base band information; base band/radio frequency transmitter/receiver unit; and parameter setting of the system processing unit. In addition, the set link state  308  monitors and maintains a stability of the link by using a feedback.          
         [0050]     Referring to both  FIG. 1A  and  FIG. 1B , the base band transmitter unit  140  uses a data and a parameter set from the system control unit  110  to frame a data according to a frame format. In addition, the base band transmitter unit  140  incorporates a function for forward error correction and a function for adjusting the bandwidth (or chip length) for a direct sequence spread spectrum. Thus, the base band transmitter unit  140  provides multiple applied functions for multiple users simultaneously. Finally, the base band transmitter unit  140  converts the framed data to a base band analog signal as an input for the radio frequency transmitter unit  150 . The base band transmitter unit  140  includes an interface controller  141 , a framer  142 , an error correction encoder  143 , a spreader  144  and a digital-to-analog converter  145 . The interface controller  141  is capable of choosing and setting the parameters of the interfaces for the base band transmitter unit  140 . For example, a frame format selection and setting for the framer  142 , or a parameter selection and setting for a scrambler, Reed-Solomon coding, an interleaver, convolutional coding, differential coding, or a spreader  144 .  
         [0051]     The framer  142  frames a data into a fixed length size from an interface integration driving unit  114 . In which, the data within the framed data can be different in sizes.  FIG. 5  shows an ESC/CSC information frame and an ESC/CSC macro synchronized information frame as another preferred embodiment of the present invention. Referring to  FIG. 5 , a frame includes two formats: an embedded signal channel (ESC) and a common signal channel (CSC). The main use of the ESC frame is to transmit a traffic information. On the other hand, the main use of the CSC frame is to transmit a network management information. Moreover, the ESC frames (or CSC frames) can be combined to form an ESC (or CSC) macro-synchronized information frame. Each of the ESC (or CSC) macro-synchronized information frames includes a number of ESC (or CSC) frames, for example, 8 ESC frames, for providing a macro synchronized information of a framer thereby adjusting the quality of the link.  
         [0052]     The error correction encoder  143  includes a scrambler and an interleaver and functions, for example, Reed-Solomon coding, convolutional coding and differential coding for organizing the frame received into a code information data having an error correction capability. Moreover, the spreader  144  is capable of generating a plurality of data packets from the code information data (from the error correction encoder  143 ) according to a direct sequence of different chip lengths. The data packets can be of different sizes. Moreover, the digital to analog converter  145  is capable of converting the data packets to the base band analog signal.  
         [0053]     The base band receiver unit  170  is used to convert an input base band analog signal to a digital signal. In addition, the base band receiver unit  170  is capable of decoding the spread spectrum, decoding the forward error correction, and de-framing a data from a frame. The base band receiver unit  170  includes an interface controller  171 , an analog to digital converter  172 , a de-spreader  173 , an error correction decoder  174  and a de-framer  175 . The interface controller  171  is capable of choosing and setting the parameters of the interfaces for the base band receiver unit  170 . For example, a frame format selection and setting for the de-framer  175 , or a parameter selection and setting for a de-spreader  173 , differential decoding, Viterbi decoding, a de-interleaver, de-Reed-Solomon coding or a de-scrambler.  
         [0054]     The analog to digital converter  172  is capable of converting the base band analog signal to a data packet. The de-spreader  173  is capable of converting a plurality of the data packets to another code information data. The error correction decoder  174  is capable of decoding the code information data received to another frame. The error correction decoder  174  includes differential decoding, Viterbi decoding, a de-interleaver, de-Reed-Soloman coding and a de-scrambler.  
         [0055]     The de-framer  175  is capable of converting the frame to a data before transmitting to the interface integration driving unit  114 .  FIG. 5  shows an ESC/CSC information frame and an ESC/CSC macro synchronized information frame as another preferred embodiment of the present invention. Referring to  FIG. 5 , a frame includes two formats: an embedded signal channel (ESC) and a common signal channel (CSC). The main use of the ESC frame is to transmit a traffic information. On the other hand, the main use of the CSC frame is to transmit a network management information. Moreover, the ESC frames (or CSC frames) can be combined to form an ESC (or CSC) macro-synchronized information frame. Each of the ESC (or CSC) macro-synchronized information frames includes a number of ESC (or CSC) frames, for example, 8 ESC frames, for providing a macro synchronized information of a de-framer thereby adjusting the quality of the link.  
         [0056]     The system processing unit is capable of providing a reference signal according to a plurality of applied parameters of the system control unit  110 , the base band signal processing unit  130 , the base band transmitter unit  140  and the base band receiver unit  170 . In which the reference signal is programmable to at least one of the base band signal processing unit, the system control unit capable, the base band transmitter and the base band receiver unit. A chip rate and a sampling rate corresponding to the chip rate are changeable according to different parameters including input data rate, Reed-Soloman code, convolutional code and spread spectrum code. The system processing unit includes: a system reference control processor  120 ; an information pulse generator  118 ; a chipping pulse generator  148  and a chipping sample pulse generator  178 . The system reference control processor  120  coordinates, manages and outputs a pulse required for each unit within the apparatus. The information pulse generator  118  generates a required reference pulse for each of the system control unit  110  and the base band signal processing unit  130 . The chipping pulse generator  148  generates a required reference pulse for the base band transmitter unit  140 . The chipping sample pulse generator  178  generates a required reference pulse for the base band receiver unit  170 .  
         [0057]      FIG. 6  illustrates a radio frequency CDMA transceiver with multiple functions and a base band CDMA transceiver with multiple functions as another preferred embodiment of the present invention. Referring to  FIG. 6 , the radio frequency transmitter unit  150  and the radio frequency receiver unit  160  can be fixed by four screws on a circuit board of the base band transmitter unit  140  and the base band receiver unit  170 .  
         [0058]     The radio frequency transmitter unit  150  is capable of converting the base band analog signal and providing a radio frequency signal for transmitting. In addition, the radio frequency transmitter unit  150  is capable of adjusting a work efficiency of a transmitting signal, selecting and setting a band frequency, and selecting and setting a bandwidth of a base band (and a radio frequency). Moreover, the radio frequency transmitter unit  150  includes a gain control functionality to adjust the actual output work efficiency of the spread spectrum. Moreover, the radio frequency transmitter unit  150  is designed to be a module and is coupled on the circuit board of the base band transmitter unit  140  and the base band receiver unit  170 . The radio frequency transmitter unit  150  includes an interface controller  151 , a low pass filter  152 , an oscillating generator  153 , a band pass filter  154  and an operational amplifier  155 . The interface controller  151  is capable of choosing and setting a plurality of interface related parameters for the radio frequency transmitter unit  150 . The parameters can be, for example, a cutoff frequency for the low pass filter  152 , frequency setting of the oscillating generator  153 , selecting and setting for the band pass filter  154  and a gain control for the operational amplifier  155 . The low pass filter  152  is capable of selecting and setting the bandwidth of the base band analog signal. The oscillating generator  153  is capable of providing a programmable stable signal source for adjusting a signal from the low pass filter. The band pass filter  154  is capable of selecting and setting the bandwidth of the radio frequency signal. Finally, the operational amplifier  155  is capable of amplifying and controlling the radio frequency signal for an output.  
         [0059]     The radio frequency receiver unit  160  is capable of receiving the radio frequency signal from the outside and re-converting back to the base band analog signal. In addition, the radio frequency receiver unit  160  is capable of adjusting a work efficiency and a gain of a receiving signal, selecting and setting a band frequency, and selecting and setting a bandwidth of a base band (and a radio frequency). Moreover, the radio frequency receiver unit  160  includes an automatic gain control (AGC) capability. A mid band signal from a spread spectrum is adjusted to a base band spectrum signal by the automatic gain control before an analog signal converter. Moreover, the radio frequency receiver unit  160  is designed to be a module and is also coupled on the circuit board of the base band transmitter unit  140  and the base band receiver unit  170 . The base bandreceiver unit  160  includes an interface controller  161 , an operational amplifier  162 , a band pass filter  163 , an oscillating generator  164  and a low pass filter  165 . The interface controller  161  is capable of choosing and setting a plurality of interface related parameters for radio frequency receiver unit  160 . The parameters can be, for example, a cutoff frequency for the low pass filter  165 , frequency setting of the oscillating generator  164 , selecting and setting for the band pass filter  163  and a gain control for the operational amplifier  162 . The operational amplifier  162  is capable of amplifying and controlling the radio frequency signal from an input. The band pass filter  163  is capable of selecting and setting the bandwidth of the radio frequency signal. The oscillating generator  164  is capable of providing a programmable stable signal source for adjusting a signal from the band pass filter. The low pass filter  165  is capable of selecting and setting the bandwidth of the base band analog signal.  
         [0060]     The experimental data of the present embodiment of the invention is mainly conducted by empirical study and proof to demonstrate the functionality and advantages of the invention. The CDMA transmitting and receiving apparatus can be implemented by two main parts namely a multiple applied functions base band CDMA transceiver and a multiple applied functions radio frequency CDMA transceiver as illustrated in  FIG. 6 . The multiple applied functions base band (or radio frequency) CDMA transceiver is responsible for transmitting and receiving signals of the base band and the spread spectrum, and is capable of providing multiple functions for an interface of an end user terminal, for example, a voicemail, a fax, an exchanger, a network, an external protected device and an interface of a multiple functions radio frequency terminal.  
         [0061]     The base band signal processing unit  130  is implemented through a chip capable of processing a voicemail and a fax, an I/O output serial communication port, a signal and information driver and a memory. The base band transmitter unit  140  and the base band receiver unit  170  can be implemented through digital signal processing (DSP), field programmable gate array (FPGA) and other related chips. The radio frequency transmitter unit  150  and the radio frequency receiver unit  160  can be implemented through a radio frequency related technology circuitry and a chip thereof. Moreover, the system processing unit can be implemented through a programmable numerical controlled oscillator (NCO) and other related filters. Moreover, the system control unit  110  can be implemented through an embedded real time micro-processor. For example, the MC68 series, a memory device and other related chips according to a specified format for transmission and by using a state machine for control and integration coupled to a network management unit, the base band signal processing unit  130  and the base band (and radio frequency) transmitter (and receiver) units  140 - 170 . Thus, the system control unit  110  is able to provide an applied interface for the network management unit, and information processing and communication through an interface to the outside, and internal control of an operation and the parameters for each unit.  
         [0062]     To summarize, the embodiments of the present invention can be applied to a VSAT CDMA communication system. In addition, the apparatus and the method thereof are able to meet the demands for multiple functions of a CDMA communication system at the same time resolve many of the communication difficulties. For example, an exchanger, a phone, a fax, a data from a network management, an external protected device and a common serial/parallel input data transmission. Here are partial results of the experimentation for referencing. The data represent different output spectrums and input constellation diagrams according to different parameter sets.  FIG. 7  shows an output spread spectrum (F c =140 MHz, FEC=½, Powers≅−10 dbm, F c,cut ≅4.4 MHz, PN length=512) as another preferred embodiment of the present invention.  FIG. 8  shows an output spread spectrum (F c =140 MHz, FEC=½, Power≅−40 dbm, F c,cut ≅4.4 MHz, PN length=512) as another preferred embodiment of the present invention.  
         [0063]     It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.