TW200920047A - Protection zone detection method and device applied to the orthogonal multiplex frequency division system - Google Patents

Abstract

A protection zone detection method and device applied to the orthogonal multiplex frequency division system mainly consists of a front end of receiving device used to transform radio-frequency signal to intermediate frequency or baseband frequency, a bandwidth detector used to detect the bandwidth of signal emitted from the base station for providing the required bandwidth information to the front end of receiving device and A/D converting unit, a A/D converting unit used to transform analog signal to digital signal for processing follow-up digital signal treatment, an energy detector used to detect the energy during a period for considering as the critical reference of follow-up units, and plural detectors of protection zone used to protect the circulation characteristic of the zone for detect whether some protection zone exist or not, and a decision-making unit of protection zone used to decide the length of the protection zone used by the base station.

Description

200920047 IX. Description of the invention: [Technical field to which the invention pertains]. The invention relates to a protection interval detecting method and device designed for orthogonal frequency division multiplexing system, in particular to a front of each orthogonal frequency division multiplex symbol in an orthogonal frequency division multiplexing system. Add a guard interval to avoid interference between symbols. When the UE wants to enter the orthogonal frequency division multiplexing system, it must first detect the guard interval length of the orthogonal frequency division multiplex symbol transmitted by the base station as a reference for subsequent initial synchronization and signal demodulation. [Prior Art] The traditional communication system uses only a single carrier to transmit data. The entire available bandwidth is only used by one user to transmit data, and the orthogonal frequency division multiplexing system is a multi-carrier modulation transmission technology. The modulation technique is to cut the entire available bandwidth into #equal, and each aliquot uses a subcarrier to transmit data. Since this technique uses subcarriers that are orthogonal to each other to transmit data' and can assign different subcarriers to different users, it is called orthogonal frequency division multiplexing. Orthogonal crossover multiplex system with high spectrum efficiency (Spectrum Efficiency) and resistance to frequency selective fading (Frequency

Selective

Fading), can resist multipath Fading, can resist Inter-Symbol Interference (ISI), can use a simple frequency domain equalizer (FDE), can use adaptive transmission Mechanisms, simplified receiver design and many other advantages. Based on the above advantages, most of the new generation of wireless communication systems use orthogonal frequency division multiplexing system as the air interfacing technology, including wireless area network (ΙΕΕΕ 802.lla/g/n Wireless Local Area Network, WLAN), Wireless Internet Network (IEEE 802.16 Worldwide Interoperability for Microwave Access 'WiMAX), Digital Video Broadcasting System (Digital Video 200920047)

Broadcasting system for Terrestrial/Handheld, DVB-T/H), Ultra Wide Band system (UWB), 3GPP Next Generation Implementation Standard (3rd Generation partner project f0I· Long-Term)

Evolution > 3GPP-LTE), etc. In an orthogonal frequency division multiplexing system, in order to avoid inter-symbol interference caused by radio multiple propagation paths, a guard interval must be added in front of each orthogonal frequency division multiplex symbol. Since this guard interval is copied from a part of the subcarrier after the orthogonal frequency division multiplex symbol, it is also called a Cyclic Prefix (CP). If the length of this guard interval is greater than the most effective delay length of the multiple propagation path, inter-symbol interference will be completely eliminated. In general, orthogonal frequency division multiplexing systems offer multiple choices of different length guard intervals for use in different communication environments. Therefore, when the UE first enters the orthogonal frequency division multiplexing system, it must first detect the length of the protection interval used by the base station to perform subsequent initial synchronization and signal demodulation. The present invention is directed to a quadrature frequency division multiplexing system, and a method and apparatus for automatically detecting different length protection intervals used by different base stations. The previous conventional orthogonal frequency division multiplexing system synchronization technology is mainly designed for the length of a single guard interval, and does not have the ability to distinguish the guard intervals of different lengths. In the following prior patent technologies, a similar concept is mentioned. 124627 00400675, 200623688. Recently, the newly proposed technology mainly adopts the parallel correlation calculation method, which has high complexity and poor detection capability for the short-length protection interval. Similar concepts are mentioned in the following prior patent technologies: 1246271 ^ 00400675 > 200623688 . 200620923 ^ 200623756 〇 This shows that there are still many shortcomings in the above-mentioned methods of use, which is not a good design, but needs to be improved. In view of the shortcomings derived from the m-method, the inventor of this case was able to improve and innovate, and after years of painstaking research, he finally succeeded in researching the 200920047 cross-frequency multiplex system and completed the application of this article to the positive device. The invention discloses a protection interval detection method and an object of the invention. The object of the invention is to provide a protection interval debt measurement method and device for design: multiplex system

In the frequency multiplex system, the user is sincere, the user wants to enter the orthogonal T-user to detect the length of the protection interval of the base: 1: > AL, as the post-parent and multi-function multiplexer The second-purpose object of the present invention is the method and apparatus for providing a different length of protection interval for the automatic port, which can reduce the need for subsequent initial synchronization. The time and the repetition are repeated using the loop of the guard interval. Since the present invention is used to implement the effect of the shield ring repeating material, the maximum processing gain can be obtained to achieve the above object of the invention. The application is applied to the orthogonal device and is detected at the user end by the base station. The protection interval and its length. Since the base station will use different lengths of protection according to the channel environment in which it is located, it is necessary to automatically detect the protection of the orthogonal frequency division multiplex symbol before the system clock synchronization is performed on the user side. Interval and its length. The protected area of the orthogonal frequency division multiplex symbol is copied from the orthogonal frequency division multiplex symbol - part of the secondary carrier, and placed in front of each orthogonal frequency division multiplex symbol. The invention relates to a method and device for automatically detecting a security interval, comprising a receiver front end, a bandwidth detector, an analog-to-digital conversion unit, an energy detector, a complex guard interval detector and a The protection interval decision unit; first, the RF signal received by the antenna is converted to the intermediate frequency or the fundamental frequency at the front end of the user receiver for subsequent analog digital conversion; next, in the bandwidth detector, the detection base The bandwidth of the signal transmitted by the station to provide the bandwidth information required by the receiver front end and the analog digital conversion unit. Next, in the analog digital to 200920047 conversion unit, the analog signal is converted into a digital signal for subsequent digital signal processing. The sampling frequency used in the conversion process is the result of the self-bandwidth detector detection. Next, in the energy detector, the accumulated energy of the received signal over a period of time is detected as a critical reference value for the subsequent unit. Since this critical reference value can be adapted to the channel environment and adaptive, it can be applied to a variety of different radio channels. This average-energy can also be used as a Receive Signal Strength Indicator 'RSI' to feed back to the base station for Adaptive Modulation Coding (AMC) or f-closed. Closed-Loop multi-antenna output (Multiple_Inpm Multiple Output, ΜΙΜΟ) technology and other applications. Next, in the first detector of the guard interval, the loop condition of the guard interval is used to detect whether the shortest guard interval specified by the system exists. If the shortest protection interval exists, it continues to detect whether the protection interval of the other length exists in the second detector to the third detector in the protection interval. The detection process is controlled by the subsequent protection interval decision unit, and the detection result is also sent to the protection interval decision unit for relevant judgment. The critical reference value used by the first detector in the protection interval is from the energy detector, and the critical reference value used by the second detector in the protection interval is from the protection interval. The detected value of a detector. In this way, the probability of false positives in the guard interval can be reduced. Finally, in the protection interval decision unit, the position and length of the final protection interval appear according to the first to the result of the measurement of the guard interval product tester. The matching filter is only required to start from the sampling point detected by the guard interval to obtain an accurate system clock and establish system synchronization. [Embodiment] The present invention is a method and device for detecting a protection interval designed by an orthogonal frequency division multi-wei system. When the user wants to enter an orthogonal frequency division multiplexing system, 200920047 is measured by the user end. The base ^^ > _ l7 σ conveys the length of the guard interval of the positive father's knife multiplex symbol. It can be used as a reference for the subsequent initial synchronization. In general, the orthogonal frequency division is more: 'two ε'', the choice of different length protection intervals, to apply to different two 1:350, when the user enters the orthogonal frequency division multiplexing system for the first time, υ Measure the length of the interval used by the base station to perform subsequent steps and signal demodulation. The present invention provides a reliable and low complexity hold detection method' and can be adaptively adjusted in different wireless communication environments. The system architecture w of the method and device for applying the u protection interval (four) to the orthogonal frequency division multiplexing system for the present invention includes: a receiver front end 1 'the receiver front end 1 is at the user end The receiver front end 1 converts the RF signal received by the antenna to the intermediate frequency or the fundamental frequency signal, and transmits the signal to the analog digital conversion unit 3 for subsequent analog digital conversion; in addition to the signal shifting, the receiver front end Processing including signal amplification, signal filtering, and frequency phase compensation will also be performed to properly reconstruct and repair the received analog signal. Since the signal transmitted by the base station may be carried in different bandwidths, such as 5 MHz, 10 MHz, and 20 MHz, the signal processing of the front end 1 of the user terminal must know the bandwidth of the signal to receive the correct signal. The bandwidth detector 2 detects the bandwidth of the signal transmitted by the base station and transmits the bandwidth signal to the receiver front end 1 and the analog digital conversion unit 3 to provide the receiver front end 1 The bandwidth information required by the analog-to-digital conversion unit 3; an analog-to-digital conversion element 3 'the analog-to-digital conversion unit 3 receives the analog signal of the receiver front end 1 and the bandwidth detector, and converts the analog signal into a digital position After the signal is transmitted to the energy detector 4 and the plurality of guard interval detectors 5 for subsequent digital signal processing, the frequency used in the conversion process is the reference self-bandwidth detector 2 The result of the detection; one-energy detector 4' the energy detector 4 detects the accumulated energy of the received signal over a period of time' and transmits the detection result to the sneak fairy 5 as a post The critical reference value of the continuation unit; a guardian number of guard interval debt detectors 5, in the first guard interval detector, the benefit of the loop: the loop characteristic of the guard interval 'detection system, whether the shortest guard interval exists, The guard interval detector may be one to κ; and the guard interval decision unit 6 is configured to determine the position and length of the final guard interval according to the detection result of the first to κ guard interval detectors. Referring to FIG. 2, the present invention is applied to the orthogonal section frequency division multiplexing system and the protection interval section of the method and the apparatus for protecting the interval, and the system uses the characteristic of the protection interval to repeat this cycle, that is, It can detect the existence of the protection interval and the position and length of the protection interval S. The length of the guard interval in the system specification is generally expressed as the ratio of the length of the orthogonal frequency division multiplex symbol to the guard interval. For example, for an orthogonal frequency division multiplex symbol having a length of 2048 subcarriers, the 1/4 guarantee interval represents a length of 5 12 subcarriers. Common protection intervals are 1/4, 1/8, 1/16, and 1/32. Please refer to FIG. 3, which is a block diagram of a bandwidth detector 2 for applying the protection interval detection method and apparatus of the orthogonal frequency division multiplexing system. The bandwidth detector 2 includes a band pass filter (Band Pass Filter, Βρρ) 21, a spectrum energy detection state 22, and a spectrum decision unit 33, wherein the input signals are respectively sent to bandpass filtering of different bandwidths. The filter 21 is configured to filter signals other than the bandwidth; the number of the band pass filters 21 and the corresponding bandwidth are determined by system specifications. For example, in a terrestrial digital video broadcasting system, the bandwidth specified by the system specification is 5. 6, 7 '8 MHz four. Thereafter, the signal is sent to the spectral energy detector 22 to calculate all the energy in each bandwidth by δ. The spectral energy of the zth possible bandwidth can be expressed as shown in equation (1): 10 200920047 P^]^\m\2dt, \<i<F (1) where is the round-in analog signal in the time domain , r, is the symbol length of the first possible bandwidth, F is the number of possible bandwidths, and the result of the estimation of the spectrum energy is sent to the spectrum decision unit 23 to determine the bandwidth used by the current base station. . In the spectrum decision unit 23, the bandwidth having the largest spectral energy will be selected' and this information is sent to the receiver front end i and the analog digital conversion unit 3. In the analog digital conversion unit 3, the analog signal is transposed to the signal for subsequent digital signal processing, and the frequency used in the conversion process is the result of the self-frequency detection by the detector 2. In the bandwidth system: 2, 'need to perform necessary signal amplification', chopping processing, and counting only frequency reduction. : Down, in the first guard interval anger detector 5, the loop condition of the guard interval is used to detect whether the shortest guard interval specified by the system exists. Referring to FIG. 4, the present invention is applied to an orthogonal frequency division multiplexing system: a block diagram of the first protection interval predator 5 of the method and apparatus for detecting. "Protection interval predator 5 is composed of a total number of vehicles, a total of 5, a delay, #sampling time 5, a complex multiplication, a table crying q ^ . , a temporary register 54, a complex subtractor ^ tired six crying The processor 56, a delay 1 sampling time 57, a span symbol 220, an absolute value 59, and a value comparison unit 60 are sent to the protection area (four) to measure 11 5 'first digital input input The signal gate 52^/plural 51 is taken to take a total of the light and complex numbers, and then sent to the delay #sample $Y to obtain the signal delay iv sampling time of the conjugate complex 51. The second traverse multiplier 53 to input the signal and delay # The sampling time block 52 outputs multiplication, as shown in the equation (2): K (w) = r(") * 〆 - γ) jSl y (2) is sent temporarily at 1: (9) is the output of the complex multiplier 53 value. This - the output will be 54 yuan. The length of the register 54 is equal to the 200920047 length of the shortest protection interval. The length is a first-in first-out (First_InFirst_0ut, FIF〇) register, and the time is output at the time („_z"the result of the complex multiplier 53.' : The output value of the complex multiplier 53 is subtracted from the output value of the register 54. The result ' of the complex subtractor 55 represents the difference between the latest delay correlation and the previous heartbeat delay, and the result is as shown in equation (3). Shown: ', (3) 57's round-out phase Next, add the result of equation (3) to the delay 1 sampling time as shown by equations (4) to (6): 〇((«'+ Ντ ~ \)%ΝΤ ) + Υ2 (η) ^ = (^%ντ),〇^<Ντ ^ Ντ=ΝΑ (6) Eight, / represents the number of the orthogonal frequency division multiplex symbol, (η % represents It is the remainder, the heart represents the length of the longest guard interval, and the horse represents the length of the orthogonal frequency division multiplex symbol after the guard interval. The 〇 = value of the delay #sample time 57 is the round-out value of the complex adder 56. Next, in the cross-symbol accumulator, the result of (4) is calculated in the past/one orthogonal frequency division multiplex symbol (including now). The same number is added to obtain a better late correlation. To obtain a result close to the longest guard interval, / can be set to a low complexity ' Η set to 1. The output value of the cross-element accumulator 58 Dedicated to the first-protection interval detector 5 (four) measured value, continued detector 5. On the other hand, the cross-symbol accumulation... output value will break the absolute value 59' to calculate the value of the value. After that, this number Boundary: the comparison of the numerical value is 6'' to determine whether the delay position of the current sampling point is between the bits according to the estimated value of the energy detector. If the value is greater than the critical reference value, the delay of the current sampling point is determined. It is located in the protection interval, and the result is sent to the protection interval decision unit 6. Otherwise, the calculation is continued Τ-姊 (4). 12 200920047 After the first protection interval detector 5 detects the existence of the shortest protection interval, The processing of the second protection interval detector 5 is continued. If the second protection interval detector 5 also detects the existence of the next protection interval, the processing of the next protection interval detector is continued, and so on. until Long κ guard interval detector 5. Please refer to FIG. 5, which is applied to the orthogonal frequency division multiplexing system, and the second interval detector 5 to the guard interval detecting method and device A block diagram of a κ guard interval detector. The block diagram is composed of a plurality of cyclic delays 501, 502, 503, a complex adder 504, a divider 5〇5, and a value comparator 506. First, the output value of the first guard interval detector 5 is sent to each of the cyclic delays 5〇1, 5〇2, 503, / is the number of the 4th interval detector 5. Each cyclic delay 5〇 The delay lengths of 丨, 502, and 503 are fixed to the length 最 of the shortest guard interval. After that, the output value of the first guard interval detector 5 is added to the output value of each cyclic delay device, and the delay correlation value of each guard interval length is obtained, and the equation (7) is obtained. Show: 〇(«') = ^1,-(«') + Ζυ.((ηLl+NT) % Ντ) 2^1-ι (7) /w=l ΖκΛη,) = ΖιΛη')+ Σ ZxAn '-m*Lx+NT)%NT) In practical applications, the result of the previous guard interval detector (Bu 7) can be accumulated to reduce the complexity. In order to normalize the delay correlation value of each guard interval length, the output value of the complex adder 5〇4 must be sent to the divider 505 for normalization. In the divider 5〇5, the divisor is 2. Finally, in the value comparison unit 506, according to the detection value of the detector 5 of the first protection interval 13 200920047 as a critical reference value, determining whether the delay position of the current sampling point is within the protection interval of the length, and detecting the result It is handled by the protection interval decision sheet 7G 6 . In this way, the probability of false positives in the guard interval can be reduced. Then, in the energy detector 4, the accumulated energy of the received signal over a period of time is detected as a critical reference value for the subsequent unit. As shown in FIG. 6, the energy detector 4 of the present invention is identical, and the energy-quantity detector 4 is composed of a conjugate complex 41, a complex multiplier 42, a register 43, and two complex numbers. Adders 44 and 45, a delay 1 sampling time 46, a span symbol accumulator 47, and an energy adjuster 48 are formed. First, the digital sample input signal is sent to the conjugate complex 41 to take its conjugate complex number. The input signal is then multiplied by its conjugate complex 41 output. The output value of the complex multiplier 42 is sent to the register 43 for storage. The length of the register 43 is equal to the length of the shortest protection zone Μ ' belongs to the first-in first-out register, and the time of the operation of the complex multiplier 42 is outputted at time w. Thereafter, the round-off value of the complex multiplier 42 is subtracted from the output value of the register 43, and the result is as follows: five (") = r(8) (8) - ^ Q Next, the complex subtraction of the equation (8) The result of the processor 44 is added to the rounding of the delay 1 sampling time 46, as shown in the equation (9): 20{η') = Ζ0, {{η'+ ΝΓ -\)%ΝΤ) + Ε(η) ( ξ • where w' and W are as shown in equations (5) and (6). The input value of the delay 1 sampling time 46 is the output value of the complex adder 45. Next, in the cross-symbol accumulator 47, The result of the calculation of the equation (9) in the past/one orthogonal frequency division multiplex symbol (including the current one) is accumulated according to the same number corresponding thereto. Finally, the result of the cross-integrator 47 is sent to the energy adjuster 48, In order to generate the final critical reference value, the energy adjuster 48 adjusts the range between 〇~丨. If the closer it is, the detection probability will increase, but the probability of false alarm 14 200920047 (False Alarm) also It will rise. If the closer to 1, the probability of false alarm will decrease, but the Miss Detection will increase. Generally, the adjustment The number can be set at 0.5. Since this critical reference value can be adjusted with the channel environment, it can be applied to various radio channels. This average energy can also be used as an indicator of the received signal strength. To the base station for adaptive modulation coding technology or closed loop multi-antenna input-output technology. 】 Finally, the first protection interval detector 5 to the κ protection interval detector detection 5 The result is sent to the protection interval decision unit 6, which determines the length of the final protection zone. Please refer to FIG. 7 , which is a protection interval detection method and device for the orthogonal frequency division multiplexing system. The decision flow chart, the operation steps of the flow chart include: ~ Step 1: Firstly, it is detected whether there is 7〇1 in the minimum protection interval. Please refer to the figure. The critical reference value used here is generated by the energy predicate. See Figure 6. ° Steps

U. Judging whether 疋 is greater than the critical reference value 702, if the first protection zone 曰4 detector (four) measurement result is greater than the critical reference value, it is determined that the current sampling point 2 position is within the protection interval, and continues to the next protection zone (four) measurement 703 in the middle of the device. Otherwise, it continues to detect the action 77.1 of the minimum guard interval. Step 3: Detecting the next protection interval 7G3' #第-protection interval system After measuring the existence of the short security, the second protection interval detection processing is continued, as shown in Figure 5. The critical reference value used here is the detected value of the =-protection interval side, and is multiplied by - adjustment parameters. Ϊ = Adjust the number of t must be greater than 〇.5, so you can reduce the false alarm and probability of the protection zone. In general, this adjustment parameter can be set to 〇8. Step 4: Determine whether it is greater than the critical reference value 704. If the detection result of the second protection zone 15 200920047 is below the critical reference value 7G5, the determined delay position is within the protection interval, and jumps to step 5. Otherwise, skip to step /, 'output is a guard interval length and related time information. Step 5: Determine whether the maximum protection interval has reached the maximum protection interval of 7〇5. If the pre-test has reached the maximum protection interval length of 7〇7, skip to step ^^, then skip to step 3 and continue to the next protection interval detector. Processing - = six: output protection interval and related time information, if the judgment of the boundary reference value in step 4 is not true, then the previous protection, information, and the end of the protection zone ... the method of measurement. If there is a second zone in step 5, the maximum protection interval length and the related time bounce are taken out, and the detection interval detection method is ended.

^ 发日(4) provides the orthogonal distribution of money: the method and device, when compared with other conventional technologies, it has the following method: 4 ways to automatically (4) different length protection zones used by different base stations: Correlation and criticality of different lengths of protection interval can automatically and accurately eliminate the refinement used by the base station where the user is located. The designed critical reference value can be adapted to the environment and applied to various radio channels. . The debrief, the _ wave of the system. The sampling is closed and the reading is accurate. 4. The invention is quite simple to implement. Each sampling point is basically only one (four) multiplication and two complex additions, which is a low complexity method. It is to be understood that the present invention is not limited to the scope of the invention, and is not intended to limit the scope of the invention. Both should be included in the scope of the patent in this case. To sum up, this case is not only innovative in terms of technical thinking, but also has many of the above-mentioned functions that are not in the traditional methods of the past. It has fully complied with the statutory invention patents of new and progressive nature, and applied for it according to law. The bureau approved the application for the invention patent, in order to invent the invention, to the sense of virtue. β [Simple diagram description] Protection interval detection of the system Figure 1 is a system architecture diagram of the method and apparatus for orthogonal frequency division according to the present invention;

Figure 2 is a schematic diagram of the protection interval applied to the orthogonal frequency division multi-device; the protection system interval detection method of the industrial system Figure 3 is the bandwidth detector of the protection and device applied to the orthogonal frequency division multiplexing system Block diagram; 〖 Wan 忐 diagram 4 is the first protection interval detector block diagram of the protection interval side method and device applied to the orthogonal frequency division multiplexing system; FIG. 5 is the application of the orthogonal frequency division multiplexing The second protection switch of the protection and measurement device of the system is the block diagram of the device and the protection zone of the quadrature frequency division multi-system (Fig. 6). Figure; and = seven are the protection interval decision-making flowcharts for the protection interval extraction method and device applied to the orthogonal frequency division multiplexing system. [Main part representative symbol] 1 Receiver front end 2 Bandwidth detector 21 Band pass filter 22 Spectrum energy detector 23 Bandwidth decision unit 3 Digital analog converter 17 200920047 4 Energy detector 41 Take conjugate complex number 42 Complex multiplier 43 register 44 complex subtractor 45 complex adder 46 delay 1 sampling time 47 span symbol accumulator 48 energy adjuster 5 guard interval detector 51 taking conjugate complex 52 delay N sampling time 53 complex multiplier 54 register 55 complex subtractor 56 complex adder 57 delay 1 sampling time 58 span symbol accumulator 59 take absolute value 60 value comparison unit 501 cyclic delay 504 complex adder 505 divider 506 numerical comparator 6 protection interval decision Unit 18

Claims (1)

200920047 X. Patent application scope: 1. A protection interval detection device applied to an orthogonal frequency division multiplexing system, when the user wants to enter the orthogonal frequency division multiplexing system, the user terminal detects the transmission of the base station.保护 Orthogonal frequency division multiplex symbol guard interval & degree, as a reference for subsequent initial synchronization 'which includes: a receiver terminal', which is to convert the RF signal received by the antenna to the front end of the user receiver to IF or baseband for subsequent analog-to-digital conversion; bandwidth anger n' money detects the bandwidth of the signal transmitted by the base station to provide the bandwidth information required by the receiver and the analog-to-digital conversion unit; The digital conversion unit converts the analog signal into a digital signal for subsequent digital signal processing. The sampling frequency used in the conversion process is the result of the self-bandwidth detector detection; The device detects the accumulated energy of the received signal over a period of time as a critical reference value for subsequent units; a plurality of guard interval detectors are first protected Between the detector y, cycle characteristics using a guard interval, the detecting system whether there is a predetermined minimum guard interval, a guard interval detector which may be first through a foot; and. The guard interval decision unit determines the position and length of the final guard interval based on the detection results of the first to κ guard interval detectors. 2. The protection interval pre-measurement device applied to the orthogonal frequency division multiplexing system according to the application scope of the patent application, wherein the bandwidth tester comprises: a plurality of band pass filters, wherein the input signals are respectively sent Entering bandpass filters of different bandwidths to filter signals other than the bandwidth, and the number of bandpass filters and their corresponding bandwidths are determined by system specifications. If the spectrum energy controller is used, it calculates the bandwidth. All the energy in the; and 19 200920047 wide, the unit, which determines the frequency used by the current base station 2; 2: the device 'where the first guard interval detector uses the guard ring feature to detect Whether the shortest protection interval specified by the system exists 'The first-protection interval detector includes: taking a common multi-unit unit, which takes a total number of samples of the digital sampling input signal; 'Sampling time unit, which will take the conjugate complex number Signal delay Ν sampling time; Ψ ^ 辛 multiplier system, multiply the input signal by the delay Ν sampling time block output; ϋ 'the output value of the complex multiplier is The first-in first-out operation results. · Output time (n_Li) at the time η. The m-method of the complex multiplier 'subtracts the output value of the complex multiplier from the output value of the register; the number adder' The result of subtracting the complex subtractor is added to the output of the delay 1 sampling time; 1 is the time when the r is sampled, and the output value of the complex adder is delayed. Orthogonal frequency division multiplex symbol (the result of the packet-exclusive signal is added according to the same number corresponding to it; / / heat ' #7L' is the absolute value of the output value of the cross-symbol accumulator; μ and The numerical comparison single % 'determines whether the delay position of the current sampling point is within the protection interval. 疋 疋 1 20 200920047 4. The protection interval applied to the orthogonal frequency division multiplexing system as described in claim 1 The detecting device, wherein the second guard interval detector to the κ guard interval detector continues to detect subsequent protection after the first guard interval detector ~ (κ_ΐ} detects the presence of the guard interval Whether the interval exists, the second guarantee The guard interval detector ~ the third guard interval detector includes: a plurality of loop delays for delaying the output value of the first guard interval detector in a cyclic manner by the length of the shortest guard interval; a complex adder The money adds the output values of the respective cyclic delays of the output value disc of the first protection interval controller; a one-divider that normalizes the delay correlation values of the lengths of the respective guard intervals; and U-values The comparator determines whether the delay position of the current sampling point is within the protection interval. 5. The protection interval detecting device applied to the orthogonal frequency division multi-wei system as described in the scope of the patent application, wherein the energy detection The detector can detect the accumulated energy of the received signal over a period of time as a critical reference value of the subsequent unit. The energy detector comprises: 〇 - taking a conjugate complex unit, which is a yoke of the digital sampling input signal Complex number; - complex multiplication n 'the system, multiplying the input signal by its complex number, · y register 'the output value of the complex multiplier is advanced The output register 'outputs the time (n_L1) of the complex multiplier at time 4; the complex subtractor subtracts the output value of the complex multiplier from the output value of the register; a complex adder Adding and subtracting the result of the complex subtractor to the output of the delay 1 sampling time; 21 200920047 A delay 〗 sampling 眭冏 1 sampling time; early 疋, delay the round-out value of the complex adder - span = accumulator , the system will calculate the results in the past "including the present", according to the knives and symbols of the gongs (including plus; and + should be the same number of tired - energy adjusters, used to shy the final 6. adjustment range Between 〇~]. /Calculation value, the quantity adjuster is applied to the orthogonal Gongxi. The protection interval decision unit measurement method is the operation step of the 7G Λ疋 final protection interval decision unit including ···, k protection interval y First detect whether the minimum protection interval exists #, the reference value is produced by the energy detector = no, the critical step 2 used to determine whether the greater than the critical reference value is greater than the critical value of the temple: , the pre-measurement position is located in the delay of the (5) sample point, ... continues the next protection interval detector, and vice versa continues to detect the minimum protection interval; * The H-zone interval detector detects the shortest protection After the existence of the interval, the processing of the second guard interval detector is continued; :: II I: whether it is greater than the critical reference value, and if the second guard interval detection is greater than the critical reference value, it is determined that the delay position of the current sampling point is located Within the material interval, and continue to determine whether the maximum protection interval has been reached', otherwise, the length of the pre-protection interval and the relevant time information are output; Step 5: Determine whether the maximum protection interval has been reached, if The detection interval of the protection interval has reached the maximum protection interval length, and the protection interval and related time information are output. Otherwise, the processing of the next protection interval detector is continued; Step 6: If the second protection interval detector detects If the result is less than the critical reference value, the output of a guard interval length and related time information is output, and the 22 200920047 ^ protection interval price measurement method is ended. If the maximum protection interval has the maximum guard interval length and related time information, and the end of the raft is detected Test method. The protection range of the protection range is applied to the orthogonal frequency division multi-u 2 interval detection method, and the detection of the first-protection interval detector of the front-only ground system is used in the third step. The value is that the adjustment parameter must be greater than 0.5. Adopted from the (four) parameters, and twenty three