Abstract:
A signal relay apparatus, method, application program, and computer readable medium adapted for wireless network are capable of saving power consumption due to failure of adjusting amplifying gain dynamically and solving the difficulty of demodulation since noise is also amplified during relay. For wireless access network, the present invention decreases the transmission power of mobile devices so that the battery of the mobile devices may keep working longer and the interference inside is reduced.

Description:
This application claims priority to Taiwan Patent Application No. 095141015 filed on Nov. 6, 2006. 
     CROSS-REFERENCES TO RELATED APPLICATIONS 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a signal relay apparatus, a method, and a computer readable medium; specifically to a signal relay apparatus, a method, and a computer readable medium capable of dynamically adjusting a gain for a wireless network. 
     2. Descriptions of the Related Art 
     Currently, a radio access network mainly consists of multiple base stations (BS) and subscriber stations (SS). With a network in which the base stations are distributed at suitable locations, the transmission should be performed in the whole area under limited transmission power. However, a shadow fading effect of signals caused by topography or man-made buildings has to be considered while a coverage range of the base stations is planned. For example, If signals are blocked by huge buildings, an effective coverage range must be reduced appropriately to ensure that the subscriber stations can still maintain transmission in its range. Alternatively, a signal relay apparatus is set up to relay signals. 
       FIG. 1  shows a diagram of a conventional signal relay apparatus  1  comprising a receiver  11 , an amplifier  12  and a transmitter  13 . The receiver  11  is configured to receive a wireless signal  14  and to convert the wireless signal  14  into a digital signal  15 . The amplifier  12  is configured to amplify the digital signal  15  to generate an amplified signal  16 . Finally, the transmitter  13  transmits the amplified signal  16  to overcome the shadow fading effect of signals and broaden a signal transmission range. 
     However, although the conventional signal relay apparatus  1  can effectively overcome the shadow fading effect of signals and broaden a signal transmission range, it can not dynamically adjust a gain of the amplifier  12  so that power consumption is considerable. On the other hand, since the amplifier  12  amplifies all received signals without difference, noise is also amplified. It makes de-modulation difficult for a device receiving the amplified signal  16 . Consequently, how to dynamically adjust the gain of the amplifier  12  according to received signals and to further enhance an overall performance of the signal relay apparatus is still an object for the industry to endeavor. 
     SUMMARY OF THE INVENTION 
     To solve the mentioned problems, an objective of this invention is to provide a signal relay apparatus of a wireless network, which comprises a receiver, a converter, a controller, an adjuster, an amplifier and a transmitter. The receiver is configured to receive a wireless signal and convert the wireless signal into a digital signal, wherein the digital signal is identifiable to a physical layer of the wireless network. The converter is configured to convert the digital signal into information, wherein the information is identifiable to a data link layer of the wireless network. The controller is configured to generate a control signal after retrieving content related to the quality of the wireless signal from the information. The adjuster is configured to generate a gain adjustment signal according to the control signal. The amplifier is configured to adjust a gain for amplifying a processed signal generated in response to the digital signal according to the gain adjustment signal. The transmitter is configured to transmit the processed signal. 
     Another objective of this invention is to provide a method for relaying signals in a wireless network. The method comprises the following steps: receiving a wireless signal and converting the wireless signal into a digital signal, wherein the digital signal is identifiable to a physical layer of the wireless network; converting the digital signal into information, wherein the information is identifiable to a data link layer of the wireless network; generating a control signal after retrieving content related to the quality of the wireless signal from the information; generating a gain adjustment signal according to the control signal; adjusting a gain for amplifying a processed signal generated in response to the digital signal according to the gain adjustment signal; and transmitting the processed signal. 
     Yet a farther objective of this invention is to provide a computer readable medium storing an application program to execute a signal relay method. The signal relay method comprises the following steps: receiving a wireless signal and converting the wireless signal into a digital signal, wherein the digital signal is identifiable to a physical layer of the wireless network; converting the digital signal into information, wherein the information is identifiable to a data link layer of the wireless network; generating a control signal after retrieving content related to the quality of the wireless signal from the information; generating a gain adjustment signal according to the control signal; adjusting a gain for amplifying a processed signal generated in response to the digital signal according to the gain adjustment signal; and transmitting the processed signal. 
     The invention can effectively solve the problems of either power consumption caused by incapability of dynamically adjusting a gain or a difficulty of de-modulation caused by amplified noise. Specifically speaking, for radio access networks, transmission power of an end device may be reduced so that power consumption is saved, usage time is extended and interferences among a system is decreased when this invention is applied at the locations distant from a base station or having highly concentrated population. 
     The detailed technology and preferred embodiments implemented for the subject invention are described in the following paragraphs accompanying the appended drawings for people skilled in this field to well appreciate the features of the claimed invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram of a conventional signal relay apparatus; 
         FIG. 2  is a diagram of a first embodiment of the invention; 
         FIG. 3  is a diagram of a receiver of a first embodiment of the invention; 
         FIG. 4  is a diagram of a packet format of a WiMAX wireless network; 
         FIG. 5  is a diagram of a first converter of a first embodiment of the invention; 
         FIG. 6  is a diagram of a second embodiment of the invention; 
         FIG. 7  is a diagram of a first de-converter of a second embodiment of the invention; 
         FIG. 8  is a diagram of a second converter of a second embodiment of the invention; 
         FIG. 9  is a diagram of a third embodiment of the invention; 
         FIG. 10  is a diagram of a second de-converter of a third embodiment of the invention; 
         FIG. 11  is a diagram of a fourth embodiment of the invention; 
         FIG. 12  is a diagram of a second de-converter of a fourth embodiment of the invention; 
         FIG. 13  is a flow chart of a fifth embodiment of the invention; 
         FIG. 14  is a flow chart of step  1300  of a fifth embodiment of the invention; 
         FIG. 15  is a flow chart of step  1302  of a fifth embodiment of the invention; 
         FIG. 16  is a flow chart of a sixth embodiment of the invention; 
         FIG. 17  is a flow chart of step  1600  of a sixth embodiment of the invention; 
         FIG. 18  is a flow chart of step  1601  of a sixth embodiment of the invention; 
         FIG. 19  is a flow chart of step  1604  of a sixth embodiment of the invention; 
         FIG. 20  is a flow chart of step  1606  of a sixth embodiment of the invention; 
         FIG. 21  is a flow chart of a seventh embodiment of the invention; 
         FIG. 22  is a flow chart of step  2100  of a seventh embodiment of the invention; 
         FIG. 23  is a flow chart of step  2106  of a seventh embodiment of the invention; 
         FIG. 24  is a flow chart of an eighth embodiment of the invention; 
         FIG. 25  is a flow chart of step  2400  of an eighth embodiment of the invention; and 
         FIG. 26  is a flow chart of step  2403  of an eighth embodiment of the invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A first embodiment of the invention is shown in  FIG. 2  which shows a signal relay apparatus  2  adapted for a WiMAX wireless network. The signal relay apparatus  2  comprises a first transceiver  200 , a filter  201 , a first converter  202 , a controller  203 , a first switch  204 , an adjuster  205 , an amplifier  206 , a second transceiver  207 , an antenna  208  and an antenna  216 . If the first transceiver  200  operates in a receiving mode, a wireless signal from a base station is going to be received. If the second transceiver  207  operates in a receiving mode, a wireless signal from a relay station, a subscriber station, or a mobile station is going to be received. In the signal relay apparatus  2 , the first transceiver  200  operates as a receiver, and the second transceiver  207  operates as a transmitter. 
     As shown in  FIG. 3 , the receiver  200  comprises a receiving filter  300 , a sample rate converter  301 , a synchronizer  302 , and a timing equalizer  303 . The receiving filter  300  may be a conventional filter adapted for a WiMAX wireless network to receive a wireless signal  209  from the antenna  208 . After receiving the wireless signal  209 , the receiving filter  300  filters and converts the wireless signal  209  into an initial digital signal  304 , wherein the wireless signal  209  comprises a packet of the WiMAX wireless network  4  in the format as shown in  FIG. 4 . The format is defined in the WiMAX specification. The sample rate converter  301  may be a conventional sample rate converter adapted for the WiMAX wireless network to perform a sample rate conversion on the initial digital signal  304  to generate an initial digital signal  305  with an adjusted sample rate. The synchronizer  302  may be a conventional synchronizer adapted for the WiMAX wireless network to perform timing synchronization and frequency tracking on the initial digital signal  305  to generate a synchronized signal  306 . The timing equalizer  303  eliminates a channel effect of the synchronized signal  306  to generate a digital signal  210 . The timing equalizer  303  may be a conventional timing equalizer adapted for the WiMAX wireless network. The digital signal  210  is identifiable to a physical layer of the network. After filtering noise by the filter  201 , the digital signal  210  becomes a transmission signal  211 . 
     As shown in  FIG. 5 , the first converter  202  comprises a fast Fourier transformer (FFT) converter  500 , a de-interleaver  501 , a de-modulator  502 , a channel encoder  503  and a de-randomizer  504 . The FFT converter  500  may be a conventional FFT converter adapted for the WiMAX wireless network to perform a fast Fourier transformation to generate a fast Fourier signal  505  after receiving the digital signal  210 . The de-interleaver  501  may be a conventional de-interleaver adapted for the WiMAX wireless network to perform a de-interleaving operation to generate a de-interleaved signal  506 . The de-modulator  502  may be a conventional de-modulator adapted for the WiMAX wireless network to generate a de-modulation signal  507  according to a predetermined de-modulation manner. Finally, the de-modulation signal  507  is sent to the channel decoder  503 , a conventional channel decoder adapted for the WiMAX wireless network, to be decoded and then sent to the de-randomizer  504 , a conventional de-randomizer adapted for the WiMAX wireless network, to be de-randomized to generate information  212  which is identifiable to a data link layer of the network. The de-modulation manner can be one or a combination of 16-Quadrature Amplitude Modulation, 64-Quadrature Amplitude Modulation, 256-Quadrature Amplitude Modulation, Binary Phase Shift Keying, and Quadrature Phase-Shift Keying. 
     Referring back to  FIG. 2 , the controller  203  receives the information  212  and retrieves a broadcast burst data  40 , a download burst data  41  and an upload burst data  42  as shown in  FIG. 4  from the information  212 . More specifically, in this embodiment the broadcast burst data  40  comprises the content of time division duplex and gain control, the download burst data  41  comprises the content of the gain control as well, and the upload burst data  42  comprises a content of signal quality. The controller  203  retrieves the content of time division duplex, gain control and signal quality to determine the quality of the wireless signal  209 . The controller  203  combines the retrieved content to form a control signal  213 . Specifically speaking, the controller  203  may be a media access control unit of the data link layer of the network. 
     According to the gain control content in the control signal  213 , the adjuster  205  generates a gain adjustment signal  214  which is well-known to those skilled in the art. The amplifier  206  adjusts a gain for amplifying the transmission signal  211  according to the gain adjustment signal  214  to analogizes the transmission signal  211  to generate an amplified transmission signal  215 . The transmitter  207  transmits the amplified transmission signal  215  via the antenna  216 . To transmit the amplified transmission signal  215 , the first switch  204  switches the transmission and receiving modes of the receiver  200  and the transmitter  207  according to the content of time division duplex in the control signal  213 . For example, while the content of time division duplex in the control signal  213  indicates it is time for receiving a signal, the first switch  204  switches the antenna  208  to the receiver  200  for receiving the signal. While the content of time division duplex in the control signal  213  indicates it is time for transmitting a signal, the first switch  204  switches the antenna  216  to the transmitter  207  for transmitting the signal. 
     The path within the signal relay apparatus  2  for the wireless signal  209  is through the receiver  200 , the filter  201 , the amplifier  206  and the transmitter  207 . The first converter  202 , the controller  203 , the first switch  204  and the adjuster  205  are configured to determine how to adjust the gain for amplifying the transmission signal  211  and how to control the operation of the receiver  200  and the transmitter  207  according to a receiving status of the wireless signal  209 . 
       FIG. 6  depicts a second embodiment of the invention which shows a signal relay apparatus  6  adapted for the WiMAX wireless network. The signal relay apparatus  6  comprises a receiver (a transceiver in a receiving mode)  600 , a first converter  601 , a controller  203 , an adjuster  205 , a first de-converter  602 , a second switch  603 , a second de-converter  604 , an amplifier  206 , a transmitter (a transceiver in a transmission mode)  207 , a first switch  204 , an antenna  208  and an antenna  216 . The receiver  600  comprises a second converter  605  and a third converter  606 . The second converter  605  receives a wireless signal  209  via the antenna  208  and digitizes it to generate an initial digital signal  607 . The third converter  606  comprises the FFT converter  500  and the de-modulator  502  of the first embodiment to perform digital waveform construction and noise elimination to generate a digital signal  608 . 
     The first converter  601  comprises the de-interleaver  501 , the channel decoder  503  and the de-randomizer  504  of the first embodiment to convert the digital signal  608  into information  212 . The controller  203  receives the information  212  and retrieves the broadcast burst data  40 , the download burst data  41 , and the upload burst data  42 . As shown in  FIG. 7 , the first de-converter  602  comprises a randomizer  700 , a channel encoder  701  and an interleaver  702 . After respectively performing a randomization, a coding and an interleaving processing by the randomizer  700 , the channel encoder  701  and the interleaver  702 , the control signal  213  is transformed to a report signal  609 . Specifically speaking, the report signal  609  represents the signal quality of the wireless signal  209 . The second switch  603  selects one of the digital signal  608  and the report signal  609  to be sent to the second de-converter  604  according to the control signal  213 . As shown in  FIG. 8 , the second de-converter  604  comprises a modulator  800 , a pilot generator  801  and an inverse FFT converter  802 . After either the digital signal  608  or the report signal  609  enters the second de-converter  604 , the modulator  800 , the pilot generator  801  and the inverse FFT converter  802  respectively processes modulation, generates a pilot signal and performs inverse fast Fourier transformation to generate a transmission signal  610 . The transmission signal  610  is then amplified, analogized, and transmitted by the amplifier  206  and the transmitter  207 . 
     In the second embodiment, the second switch  603  operates according to the content of time division duplex in the control signal  213 . While the second switch  603  selects the digital signal  608  to be sent to the second de-converter  604 , the path in the signal relay apparatus  6  for the wireless signal  209  is through the receiver  600 , the second de-converter  604 , the amplifier  206  and the transmitter  207 . While the second switch  603  selects the report signal  609  to be sent to the second de-converter  604 , the path in the signal relay apparatus  6  for the wireless signal  209  is through the receiver  600 , the first converter  601 , the controller  203 , the first de-converter  602 , the second de-converter  604 , the amplifier  206  and the transmitter  207 . In other words, the transmission time of the digital signal  608  and the report signal  609  is determined according to time division duplex. 
       FIG. 9  depicts a third embodiment of the invention which shows a signal relay apparatus  9  adapted for the WiMAX wireless network. The third embodiment has a similar structure as the second embodiment. Only the differences will be described hereinafter. The third embodiment comprises a receiver (a transceiver in a receiving mode)  90 , a first converter  91 , a first de-converter  92  and a second de-converter  93 . The receiver  90  comprising the second converter  605 , the third converter  606 , the de-interleaver  501  and the channel encoder  503  receives the wireless signal  209  via the antenna  208 , performs digital waveform construction to eliminate interference due to noise, and eliminates data errors caused by the channel effect via the de-interleaver  501  and the channel decoder  503  to generate a decoded digital signal  94 . The first converter  91  comprises the de-randomizer  504  only to convert the decoded digital signal  94  into the information  212 . The first de-converter  92  de-converts the control signal  213  to generate a report signal  95 , wherein the first de-converter  92  is the randomizer  700 . As shown in  FIG. 10 , the second de-converter  93  comprises the channel encoder  701 , the interleaver  702 , the modulator  800 , the pilot generator  801  and the inverse FFT converter  802 . The second de-converter  93  performs the conversions on either the decoded digital signal  94  or the report signal  95  to generate the transmission signal  610 . The transmission signal  610  is then amplified, analogized, and transmitted by the amplifier  206  and the transmitter  207 . 
     In the third embodiment, the second switch  603  operates according to the content of time division duplex in the control signal  213 . While the second switch  603  selects the digital signal  94  to be inputted to the second de-converter  93 , a path in the signal relay apparatus  9  for the wireless signal  209  is through the receiver  90 , the second de-converter  93 , the amplifier  206  and the transmitter  207 . While the second switch  603  selects the report signal  95  to be inputted to the second de-converter  93 , a path in the signal relay apparatus  9  for the wireless signal  209  is through the receiver  90 , the first converter  91 , the controller  203 , the first de-converter  92 , the second de-converter  93 , the amplifier  206  and the transmitter  207 . In other words, the transmission time of the digital signal  94  and the report signal  95  is determined according to time division duplex. 
       FIG. 11  depicts a fourth embodiment of the invention which is a signal relay apparatus  11  adapted for the WiMAX wireless network. This embodiment has a similar structure as the third embodiment and only the differences are described hereinafter. The fourth embodiment comprises a receiver (a transceiver in a receiving mode)  1100 , a controller  1102  and a second de-converter  1101 . In contrast with the receiver  90  of the third embodiment, the receiver  1100  further comprises the de-randomizer  504 . Therefore, the receiver  1100  receives the wireless signal  209  via the antenna  208 , performs digital waveform construction to eliminate interference due to noise, eliminates data errors caused by the channel effect via the de-interleaver  501  and the channel decoder  503 , and supports different transmission modes, such as a relay link and a access link, because of the newly added de-randomizer  504  to generate the information  212 . The controller  1102  further comprises a second switch  603  to generate the control signal  213  and the report signal  609  according to the information  212 . As shown in  FIG. 12 , the second de-converter  1101  comprises the randomizer  700 , the channel encoder  701 , the interleaver  702 , the modulator  800 , the pilot generator  801  and the inverse FFT converter  802 . The second de-converter  1101  de-converts the report signal  609  to the transmission signal  610 . The transmission signal  610  is then amplified, analogized, and transmitted by the amplifier  206  and the transmitter  207 . 
     In the fourth embodiment, a path in the signal relay apparatus  11  for the wireless signal  209  is through the receiver  1100 , the controller  1102 , the second de-converter  1101 , the amplifier  206  and the transmitter  207 . The first switch  204  and the adjuster  205  are configured to determine how to adjust the gain for amplifying the transmission signal  609  and how to control the operation of the receiver  1100  and the transmitter  207  according to a receiving status of the wireless signal  209 . 
       FIG. 13  depicts a fifth embodiment of the invention which shows a flow chart of a signal relay method adapted for a WiMAX wireless network. The method is applied to the signal relay apparatus  2  as described in the first embodiment. In the first step  1300 , the first transceiver receives the wireless signal  209  via the antenna  208  to generate a digital signal  210 . For a more detailed description, step  1300  further comprises steps as shown in  FIG. 14 . In step  1400 , the receiving filter  300  receives the wireless signal  209  from the antenna  208  to filter and convert into the initial digital signal  304 . In next step  1401 , the sample rate converter  301  performs the sample rate conversion on the initial digital signal  304  to generate the initial digital signal with adjusted sample rate  305 . In next step  1402 , the synchronizer  302  performs timing synchronization and frequency tracking on the initial digital signal  305  to generate the synchronized signal  306 . In final step  1403 , the timing equalizer  303  generates the digital signal  210  after eliminating the channel effect of the synchronized signal  306 . Now back to  FIG. 13 , in step  1301  the filter  201  filters the noise of the digital signal  210  to generate the transmission signal  211 . 
     In step  1302 , the first converter  202  converts the digital signal  210  into the information  212 . For a more detailed description, step  1301  further comprises steps as shown in  FIG. 15 . In first step  1500 , the FFT converter  500  performs the fast Fourier transformation to generate the fast Fourier signal  505  after receiving the digital signal  210 . In next step  1501 , the de-interleaver  501  de-interleaves the fast Fourier signal  505  to generate the de-interleaved signal  506 . In step  1502 , the de-modulator  502  performs de-modulation according to the pre-determined manner to generate the de-modulation signal  507 . In final steps  1503  and  1504 , the channel decoder  503  and the de-randomizer  504  performs decoding and de-randomizing to generate the information  212  respectively. 
     Back to  FIG. 13 , in step  1303  the controller  203  receives the information  212  to generate the control signal  213 . In step  1304 , the adjuster  205  is configured to generate the gain adjustment signal  214  according to the gain control content of the control signal  213 . In step  1305 , the amplifier  207  adjusts the gain of the transmission signal  211  according to the gain adjustment signal  214  and analogizes the transmission signal  211  to generate the amplified transmission signal  215 . In step  1306 , the first switch  204  switches the transmission and receiving modes of the receiver  200  and the transmitter  207  according to the content of time division duplex in the control signal  213 . In step  1307 , the transmitter  207  transmits the amplified transmission signal  215  via the antenna  216 . 
     Except mentioned steps, the fifth embodiment can further execute operation and method described in the first embodiment. 
       FIG. 16  depicts a sixth embodiment of the invention which shows a flow chart of a signal relay method adapted for the WiMAX wireless network. The method is applied to the signal relay apparatus  6  as described in the second embodiment. In the first step  1600 , the receiver  600  receives the wireless signal  209  via the antenna  208  and converts the wireless signal  209  into the digital signal  608 , wherein the receiver  600  further comprises the second converter  605  and the third converter  606 . The third converter  606  further comprises the FFT converter  500  and the de-modulator  502  as shown in the first embodiment. Consequently, step  1600  further comprises steps as shown in  FIG. 17 . In first step  1700 , the second converter  605  receives, filters and converts the wireless signal  209  to the initial digital signal  607 . In next step  1701 , the FFT converter  500  performs the fast Fourier transformation on the initial digital signal  607  to generate a fast Fourier transform signal. In next step  1702 , the de-modulator  502  performs de-modulation on the fast Fourier transform signal to generate the digital signal  608 . 
     Back to  FIG. 16  to execute step  1601 , the first converter  601  converts the digital signal  608  into the information  212 , wherein the first converter  601  comprises the de-interleaver  501 , the channel decoder  503  and the de-randomizer  504  of the first embodiment. Consequently, step  1601  further comprises the steps shown in  FIG. 18 . In first step  1800 , the de-interleaver de-interleaves the digital signal  608  to generate a de-interleaved signal. In next step  1801 , the channel decoder  503  decodes the de-interleaved signal to generate a decoded signal. In final step  1802 , the de-randomizer  504  performs de-randomizing on the decoded signal to generate the information  212 . Back to  FIG. 16  again, in step  1602  the controller  203  receives the information  212  and retrieves the broadcast burst data  40 , the download burst data  41  and the upload burst data  42  of the packet format of the WiMAX wireless network  4  as shown in  FIG. 4  to generate the control signal  213 . In step  1603 , the adjuster  205  is configured to generate the gain adjustment signal  214  according to the gain control content of the control signal  213 . In next step  1604 , the first de-converter  602  converts the control signal  213  to generate a report signal  609 , wherein the first de-converter  602  further comprises the randomizer  700 , the channel encoder  701  and the interleaver  702 . Consequently, step  1604  further comprises the steps as shown in  FIG. 19 . In step  1900 , the randomizer  700  randomizes the control signal  213  to generate a randomizing signal. In next step  1901 , the channel encoder  701  performs coding on the randomizing signal to generate a coding signal. In final step  1902 , the interleaver  702  interleaves the coding signal to generate a report signal  609 . Specifically speaking, the report signal  609  represents for signal quality of the wireless signal  209 . 
     Back to  FIG. 16  to execute step  1605 , the second switch  603  switches one of the digital signal  608  and the report signal  609  to the input of the second de-converter  604  according to the control signal  213 . In next step  1606 , the second de-converter  604  converts the inputted signal to generate the transmission signal  610 , wherein the second de-converter  604  further comprises the modulator  800 , the pilot generator  801  and the inverse FFT converter  802 . For a more detailed description, step  1606  further comprises the steps shown in  FIG. 20 . In steps  2000 ,  2001 ,  2002 , the modulator  800 , the pilot generator  801  and the inverse FFT converter  802  processes modulating, generates a pilot signal and performs inverse fast Fourier transformation to generate a transmission signal  610  respectively. In step  1307 , the first switch  204  switches the transmission and receiving modes of the receiver  600  and the transmitter  207  according to the content of time division duplex in the control signal  213 . In final step  1308  and step  1309 , the amplifier  206  and the transmitter  207  amplifies, analogizes, and transmits the transmission signal  610  respectively. 
     Except mentioned steps, the sixth embodiment can further execute operation and method described in the second embodiment. 
       FIG. 21  depicts a seventh embodiment of the invention which shows a flow chart of a signal relay method adapted for a WiMAX wireless network. The method is applied to the signal relay apparatus  9  as described in the third embodiment. In the first step  2100 , the receiver  90  receives the wireless signal  209  and generates the decoded digital signal  94 , wherein the receiver  90  further comprises the second converter  605 , the third converter  606 , the de-interleaver  501  and the channel decoder  503 . For a more detailed description, step  2100  further comprises the steps as shown in  FIG. 22 , wherein steps  2200 ,  2201  and  2202  are the same as steps  1700 ,  1701 , and  1702  of the sixth embodiment and thus no unnecessary details are given here. In steps  2203  and  2204 , the de-interleaver  501  de-interleaves the de-modulation signal and the channel decoder  503  eliminates data errors caused by the channel effect to generate the decoded digital signal  94 . In step  2101 , the first converter  91  converts the decoded digital signal  94  to generate the information  212 , wherein the first converter  91  is indeed the de-randomizer  504 . In next step  2102 , the controller  203  receives the information  212  to generate the control signal  213 . In step  2103 , the adjuster  205  is configured to generate the gain adjustment signal  214  according to the gain control content of the control signal  213 . In step  2104 , the first de-converter  92  de-converts the control signal  213  to generate the report signal  95 , wherein the first de-converter  92  is indeed the randomizer  700 . In step  2105 , the second switch  603  also switches one of the digital signal  94  and the report signal  95  to the input of the second de-converter  93  according to the control signal  213 . In step  2106 , the second de-converter  93  converts either the digital decoded signal  94  or the report signal  95  to generate the transmission signal  610 , wherein the second de-converter  93  comprises the channel encoder  701 , the interleaver  702 , the modulator  800 , the pilot generator  801  and the inverse FFT converter  802 . For a more detailed description, step  2106  further comprises steps as shown in  FIG. 23 . In first step  2300  and step  2301 , the channel encoder  701  and the interleaver  702  codes and interleaves the received signal to generate an interleaving signal respectively. The following steps  2302 ,  2303  and  2304  are the same as the steps  2000 ,  2001  and  2002  of the sixth embodiment and thus no unnecessary details are given here. In next step  2107 , the first switch  204  switches the transmission and receiving modes of the receiver  90  and the transmitter  207  according to the content of time division duplex in the control signal  213 . In final step  2108  and step  2109 , the amplifier  206  and the transmitter  207  amplifies, analogizes, and transmits the transmission signal  610  respectively. 
     Except mentioned steps, the seventh embodiment can further execute operation and method described in the third embodiment. 
       FIG. 24  depicts an eighth embodiment of the invention which shows a flow chart of a signal relay method adapted for a WiMAX wireless network. The method is applied to the signal relay apparatus  11  as described in the fourth embodiment. In the first step  2400 , the receiver  1100  receives the wireless signal  209  and converts it to information  212 . For a more detailed description, step  2400  further comprises the steps as shown in  FIG. 25 . In step  2500 , the second converter  605  receives the wireless signal  209  to filter and convert to an initial digital signal. In next step  2501 , the FFT converter  500  performs the fast Fourier transformation on the initial digital signal to generate a fast Fourier transform signal. In next step  2502 , the de-modulator  502  de-modulates the fast Fourier transform signal. In next step  2503  and step  2504 , the de-interleaver  501  de-interleaves the de-modulated signal and the channel decoder  503  eliminates data errors caused by the channel effect to generate a decoded signal. In step  2505 , the de-randomizer  504  de-randomizes the decoded signal to generate the information  212 . 
     In next step  2401 , the controller  1102  generates the control signal  213  and the report signal  609  according to the information  212 . In step  2402 , the adjuster  205  is configured to generate the gain adjustment signal  214  according to the gain control content of the control signal  213 . In step  2403 , the second de-converter  1101  de-converts the report signal  609  to generate the transmission signal  610 . For a more detailed description, step  2401  comprises the steps as shown in  FIG. 26 . In step  2600 , the randomizer  700  randomizes the inputted signal to generate a randomizing signal. In step  2601 , the channel encoder  701  performs coding for the randomizing signal to generate a coding signal. The following steps  2602 ,  2603 ,  2604  and  2605  are the same as steps  2301 ,  2302 ,  2303  and  2304  of the sixth embodiment and thus no unnecessary details are given here. In next step  2404 , the first switch  204  switches the transmission and receiving modes of the receiver  1100  and the transmitter  207  according to the content of time division duplex in the control signal  213 . In final step  2405  and step  2406 , the amplifier  206  and the transmitter  207  amplifies, analogizes, and transmits the transmission signal  610  respectively. 
     Except mentioned steps, the eighth embodiment can further execute operation and method described in the fourth embodiment. 
     The methods may be implemented via an application program which stored in a computer readable medium. The computer readable medium can be a floppy disk, a hard disk, an optical disc, a removable disk, a tape, a database accessible from a network or any storage medium with the same functionality which can be easily thought by people skilled in the art. 
     According to above descriptions, the invention can improve drawbacks of the prior art signal relay apparatus. The invention has functionality to dynamically adjust the gain to effectively solve power consumption caused by the incapability to dynamically adjust the gain. Furthermore, the de-modulation difficulty for the de-modulation device to receive the signal caused by the noisy signals amplified together is solved. On the other hand, the invention can regenerate the received signal to reduce an error ratio of the signal. 
     The above disclosure is related to the detailed technical contents and inventive features thereof. People skilled in this field may proceed with a variety of modifications and replacements based on the disclosures and suggestions of the invention as described without departing from the characteristics thereof Nevertheless, although such modifications and replacements are not fully disclosed in the above descriptions, they have substantially been covered in the following claims as appended.