TW567686B - Method and apparatus for cell search for W-CDMA - Google Patents

Abstract

The invention discloses a cell search method for the CDMA system, using three stage cell search. The method comprises the steps of: matching an incoming signals from the basestation; over-sampling the incoming signals N times against a chip rate and outputting N over-samples (Y1(k), Y2(k), ... YN(k)); down-sampling the incoming signals and outputting the N over-samplers to N parallel signal paths, and proceeding the N over-samples serially in a first stage process, a second stage process and a third stage process to accomplish a trial; wherein the N over-samples are used differently in the first stage process, the second stage process and the third stage process controlled by a control process. A cell search method of the present invention can be used for reducing simultaneously the effects of non-ideal sampling and clock offset, and to accomplish fast cell search. Another, the invention also discloses a cell search apparatus for realizing the cell search apparatus under the effects of non-ideal sampling and clock offset in the system without increasing the hardware complexity.

Description

567686 V. Description of the invention α) [Field of the invention] The present invention relates to a cell search method and device for a code division multiple access system (CDMA), and more particularly to a method for searching for cells. Cell search method and device of wide band division multiple access (W-CDMA) system, the method and device can reduce the effects of non-ideal sampling and sampling frequency offset in the system at the same time of clock offset) 0 [Previous technology] A ce 1 1 u 1 arsystems using a direct sequence spread spectrum code division multiple access technology ) Significantly increase channel capacity. This system has attracted considerable attention in recent research on mobile communication systems. Generally speaking, due to the nature of frequency reuse (freqUenCy reuse), the bandwidth efficiency (bandwidth ef f iciency) of the code division multiplex access system is higher than that of other multiplex access systems (such as frequency division multiplex access and time). Multiple access) is even better. In addition, cell planning (cel 丨-multiplexing access system is quite simple. Therefore, the multiplexing access system will be the mainstream of the future. Especially the third generation partnership plan (Third generation partnership project, 3GPP) Wideband Code Division Multiplexing

The access / division duplex (¥ -00 ^^ /? 00) system has been adopted as one of the standards for IMT-2 0 0 0 third generation systems. In a cellular system with one-code multiplex access, the user equipment (UE equipment, UE) as the method to search for the best cell is called "cell"

Page 6 567686 V. Description of the invention (2) * Search for '' (c e 1 1 s e a r c h). A fast cell search system is very important. In order to reduce the user device's turn-on delay (initial search), increase standby time (idle search), and handover ( Active mode search) maintains good communication link quality. See U.S. Patent No. 6, 0 38, 2500 issued to Shou et al., Whose title is "Initialization of Synchronization Method and Direct-Sequence Code Division Multiplexing Access Receiver for Asynchronous Cell System Receiver" ( I nitia 1 Synchronization Method And Receiver for DS-CDMA Inter Base Station Asynchronous Cellular System) Reveals an initialization synchronization method for high-speed searched cells and a receiver for direct-sequence-based multiplexing access relays asynchronous Cell system. A baseband acceptance signal is input to a matched filter and is associated with a spreading code provided by a spreading code generator. A signal electric power calculator calculates the relevant round-out electric power of the matched filter, and outputs the result to a long code synchroniziation timing determiner, a threshold value & V calculator ) And long code identifier (10ng code identifier). During the initial cell search period, the spread-spectrum code generator outputs a short code which is common to the control channel of each base station. After the long code synchronization schedule has been determined, each chip of the N chips that make up a part of the synthesized spreading code sequence is successively replaced and output. See U.S. Patent No. 6, 1 85, 244, issued to Nystrom et al., Entitled "Cell Search in Code Division Multiplexing Access Communication System," (Ce i 1

Page 7 567686 V. Description of the invention (3) searching in a CDMA communications system) 'Reveals that during cell search during a multiplexed multiplex access communication system, a more efficient coding schedule requires a long code and frame time schedule. . A code set with an M Q-ary codeword length, where the codeword includes a set from a Q short code, the code set is defined to a specific characteristic. The satisfied initial characteristic is that the codeword has no cyclic drift and thus generates a valid codeword; other satisfied characteristics are that there is a one-to-one mapping between the long code message and the valid codeword. And the encoder will be able to detect random movements that occur in interference and noise (hence the time frame of the code frame) and the transmitted codewords (ie, related to long code indication messages), with Some degree of precision and reasonable complexity. See U.S. Patent No. 6, 28.9, 07, issued to Kim et al., With the title π-a method for obtaining a Sogo cell base station in a non-synchronous multiplexing mobile communication system , "(Method for Acquiring A Cell Site Station in Asynchronous CDMA Cellular

Communication Systems), revealing a group code and cell code are multiplexed and used as a pilot code (pi 1 〇tc 〇de), the guide code is used for asynchronous cell division code multiplexed access communication There are different bases σ in the system. The use of the evening transmission code 'interference is reduced due to the use of two pilot codes. A method for obtaining a search cell base station in a non-synchronous code division multiplexed mobile communication system includes a base station controller, a plurality of mobile stations and base stations, and different base stations using different sequences. The search cell ^ The steps of the floor method include (a) designating the cell code of the cell as the guide code of the inphase channel of the base station (b) designating the cell code of the cell as

567686 V. Description of the invention (4) The pilot code of the quadrature channel of the base station (c) Multiplex transmission of the pilot code of the inphase channel and the quadrature channel and generation together Matches a quarter of the boot code.

Please refer to the first figure, which will help to understand the frame structure of a third-generation cooperative computing day-to-day (3 G P P) system. First, in the third-generation cooperative computing day-to-day (3gpp) wideband code division multiplexed access / frequency division multiplexed system, the cell search system is typically completed by three stages, which include Two specially designed synchronization channels (SCH) and a common pilot channel (CPICH). In the first stage 110, the 'primary synchronization channel (PSCH) 111 is used for slot synchronization. The primary synchronization channel 111 includes a primary synchronization code (PSC) defined as aCp, where “a” (= ± 1) depends on the presence or absence of diversity transmission transmitted at the base station. In the second stage 120, a secondary synchronization channel (SSCH) 12l is used for frame / code group identification. The secondary synchronization channel 121 contains secondary synchronization codes (SSCs) defined as acs, where the coefficient is 3

Coefficient equivalent to the primary synchronization channel. In the third stage 130, the common V channel 131 is used for the decision of downlink scrambling co o de e. As shown in the figure, 15 time slots are included in the 10 millisecond (ms) code frame, and because 3.84 million chips per second are used in this system

Page 9 567686 V. Description of the invention (5) (Mchips / sec) speed. Therefore, each code box contains 3840 pieces of stone horses, that is, each time slot contains 2560 pieces of chips. In addition, the length of the primary synchronization channel and the secondary synchronization channel include 256 chips and are transmitted only at the beginning of the slot boundary. The traditional cell search for the 3rd Generation Partnership Project (3GPP) wideband code division multiplexed access / frequency division multiplexed system can be divided into two general categories: serial search and ducted (Pipelined) search. As shown in Figure 2, before the next new search starts, the sequential search needs to go through three synchronization stages in sequence, which are (1) time slot synchronization (s 1 〇tsynchr ο nizati ο η) (2) code frame Synchronization / code group decision

synchronization / code group identification) (3) scrambling code identification. Please refer to the first (a) diagram. The violation diagram is a simplified diagram for the traditional three-stage sequential (s e r i a 1) cell search process. For simplicity, a complete three-stage search will be referred to as an experiment (t r i a 1). In sequential cell search, try_ does not overlap until the search is successful, that is, there can be only one phase in action at a time, that is, there is only one box in a time '~: (dagger 1 ( ^ 1021 Boxes 212 and 213 are in action (each box represents a certain stage of a test), so it consumes lower power loss, but takes longer search time. In addition, as As shown in Fig. 2 (b), the three stages of catheter-type ㈧ 丨 ^ 丨 丨 ^ are performed simultaneously. In order to introduce the catheter-type search in detail, the figure is used for the three-stage catheter-type cell search process. Simplified diagram. In the catheter search, the detection at different stages is performed simultaneously, that is, the test

Page 10 567686 V. Description of the invention (6) and test v overlap. For example, Box 3 11, Box 3 2 1 and Box 3 3 1 are in the same test. Obviously, in ducted search, there are more possible trials in a fixed, in-room, and therefore a faster search. Of course, the price paid is greater power consumption. In order to speed up cell search ', this catheter search is more widely used. 1 Note that for catheterized searches, hardware devices are not required compared to sequential cellular searches. For example, if we assume that each stage takes 1 ϊ seconds, and if the cell search succeeds in the Kth test, the cell search time required for a mother search is (κ + 2) x 10 milliseconds (= ); In contrast, a sequential search requires b 30 milliseconds (μ). Eight = ^, there are two basic assumptions in the prior art generally used in the third-generation cooperative project wideband code division multiplexed access / 1-cell cell search. The chip "chi p-matched fi Iter" output (ideal sampling). However, in practice, the sampling system at chip-matched filter t = is not perfect (ie, non-ideal sampling). Second, the d chip time has been accurately known to the receiver system (that is, no fetching or catching). That is, the = Ϊ f rate is set without a frequency offset. In fact, the frequency ί ΐ i offset) is derived from the crystal of the user device. The frequency of the incoming signal carrier frequency is frequency offset, and the part of the sampling frequency offset # _ / ΐ ΪI is not taken into account. This frequency offset causes sampler abundance to exist between the base station and the user device. Please refer to Table 1.

Article-567686 V. Description of the invention (7) The table shows that the sampling frequency generated under different frequency offsets is $, for example, in the presence of a 12kHz frequency offset, in a 30 millisecond code box There will be an offset of 0.69 times the chip time, which is equivalent to a sampling offset of 6 ppm. This will cause error information and increase the cell search time. In the following month, 'we focus more on solving the case where the frequency offset is less than 6 ppm', but the present invention is not limited to this. The second (a) and third (b) diagrams are not the prior art, but are observation diagrams of the inventor's primary code matching filtering as the output under the consideration of the chip offset time effect caused by the f frequency offset. As shown in the third figure (㈧ and third (b)), under the sampling frequency shift effect caused by the frequency shift, the signal level is reduced and the inter-chip interference is increased. [Summary of the invention] The main features of the present invention The purpose is to provide a cell search method for code division multiplexing access systems, more specifically for wideband code division multiplexing access systems, which can be used to reduce non-ideal sampling effects and sampling frequency offset effects in the system and quickly Complete the cell search. To achieve the secondary purpose of the present invention, the secondary purpose of the present invention is to provide a cell search device, a multiplexed access system, and more particularly, a non-ideal system for a wideband multiplexed multiplexed access system. Sampling effect and sampling frequency offset effect cell search device without increasing the complexity of the hardware. In order to achieve the above-mentioned main purpose, the present invention provides a cell search method for a code division multiplexing access system, and more particularly used Under the wide-frequency division code multiplexed access system, the non-ideal sampling effect and the sampling frequency offset effect are reduced. The first stage has a primary synchronization channel (PSC Η) for Slot synchronization; a first

567686 V. Description of the invention (8) The second stage has a secondary synchronization channel (SSCH) which is synchronized in the time slot and frame / code group identification; and the third stage has a common guidance pass V ^ 'for the determination of the scrambled code. According to the present invention, the method includes (, PICH) matching an incoming signal from one of the base stations; over-sampling the sequence ~ steps, · chip rate N times and outputting the over-sampling ^ Sample input / number is a Y200 ,,, YN (k)); downsample the incoming signal and ^^ "(1 ° 'sample point to N parallel signal paths; the n oversampling points: Out of the N take-stage processing, a second-stage processing and a third-stage processing; a first test (tria 1) is performed in sequence; where by a control process, the == to complete a first-stage processing, the The second stage of processing and the third sample are used in different ways. — ^ #The experiment in which the cell is searched for in the process further includes the following steps. # One of the access signals can be time-slot synchronized; In the first stage of processing, it is detected that one code group of the incoming signal is synchronized with the code frame. Second, during processing, selecting one of the incoming signals disturbs the value of $; Xi 2 is the value at the third stage. As a first authentication; If the scramble code and a gate are selected, the scramble code selected will be subjected to a second check. J: will restart;% pass the second check The test is successful, otherwise, if the scrambled code passes between T p milliseconds (ms), the test is restarted. 4. At a delay, according to one of the features of the present invention, the sampling point is straightened. Select an optimal point. According to another feature of the present invention, the manufacturing process further includes the following steps:

Page 13 of the invention description (9): In the first stage of processing, at the \ sampling point, and transfer to the second stage of smoke oversampling in the three stages of the test. Reason and the first = touch ρ ^ also% take. ~ Steps at i li%, in order to enter five steps and one step is based on one of the features of the present invention, complex "is bad again, ^: in the first stage processing, The second-stage J; manufacturing process further includes: 卞 random and independent processing in the N over-fetching & processing and the third stage ^ cleverly in each stage of the test. Point selection ~ sampling; when hard, the present invention A cell search f Q system is also provided, more specifically for wideband code division and multiple channels, and for the channel of multiple code division stages. The first stage has a system. The device processes 1 system for time slots. Synchronization; the second phase has: primary synchronization channel (psci) time slot synchronization, used for code frame / code group identification, and synchronization channel (SSCH) is used in the pilot channel (CPICH) for downloading gift codes and The third stage has a common decision of a cell for a code division multiplexing access system. According to the present invention, a chip-matching filter is used, and the number device is used to search for a loading signal in the cell; a sampling element Γ is connected to the 詨 code, and one of the base stations enters the incoming signal to fetch i, Equipped with a filter for, sample points (Yi (k), Y2 (k) ,,, ⑴ren sub-round over-sampling N! ^ Yuan to round out the heart to the first-down sampler , Connected to the second brother & detector and the third-stage inspection first-stage detector, the cattle down the sampler, used to obtain :; stomach first-stage detection synchronization, the second-stage detection Cry, even when the jj enters one of the signals, the slot group is synchronized with the code frame. The sampler is used to obtain the sampler that is used to determine the entry to the three-stage detector. w now one scramble code; one control

Page 14 ^ 00 May 2nd invention description (10) _____ π-made pieces, connected to the first stage detector, the third stage detector, for the second stage detector, the second stage detector and section The detector, the second stage inspection, the ^ th > oversampling point are used in the first stage; and an authentication unit is used in the third stage detector to determine whether the test is successful. 'The authentication unit connected to the third-stage detector further includes a state for testing output from the third ratio =, which is connected to the third-stage detection and comparison; a first decision component factory, 1 Whether the scrambling code and a gate value of 77 5 yards are correct; if so, the two comparators determine that the failure is considered a failure, and a new test does not exceed the value of Λ] Λ, then the test results in the gate. If the blocking value is exceeded ν, S will be restarted if it is late, otherwise, such as the proof unit; the synchronous verification unit, the δ δ scrambling code will enter a synchronization verification to verify the scrambling code; and an i-th link to The first decision element is a unit for determining the scramble code element, and is connected to the second verification element that has been synchronously verified, then try 1 and accept; wherein if the scramble code delay time is TP milliseconds (IDS) Duplicate two f two work, otherwise a new test in one ^ According to a feature of the present invention, complex; k: control of control elements, in the fine & the first stage detector by gold-control according to the present The special feature of the invention: Select the best sample point in the second sample. The control of the control element, in the first stage of the __ / hai the detector uses the control point & 彳 t ~ randomly select a sample in the ^ Caiguo pass recognition point; to two who run f the second stage The detector and the third-stage detection kit continue to perform the three-stage cell search. According to a feature of the present invention, the first phase detection is performed, and the first phase detection is controlled by the control element, the first phase white detector and the third phase detection.

Detectors are randomly and independently processed in the N detectors at each stage. It is easy to see from the detailed description below. s c h e m e). If the system has both non-ideal sampling effect and sampling frequency offset effect, the control process should introduce the cell search method into a random sampling scheme. In the implementation of the device, the attached drawings

567686 Select a sampling point from the oversampling points. Other features and advantages of the present invention will be revealed by the patent scope defined by the invention. [Detailed description of the invention] Fourth, a control process using a cell search method of the present invention 1 Because the method and device of the present invention consider the non-ideal sampling effect and sampling frequency offset effect in the system at the same time. Therefore, the present invention provides different embodiments applicable to different situations. As shown in the figure, if the system has a non-ideal sampling effect but no sampling frequency offset effect, the control process should introduce the cell search method into a pre-selection strategy (pre-selection). The control process can be performed by a control element. The fifth figure shows a cell search method according to the first embodiment of the present invention, which uses a pre-selection strategy, or a serial test in stage-1 (STS1) method. As shown in the five figures, each box represents a certain stage of a certain test. For example, box 5 i represents the first stage of processing, box 5 2 1 represents the second stage of processing and box 5 3 1 The system represents the third stage of processing. According to the present invention, a total of 5 1 2 scrambling codes are used in different cells at the time of downloading, and are reused throughout the system. The code is subdivided into 6 4 groups, Each group has 8 codes. Each code frame is 3 384 chips long and is therefore extended to the entire code frame.

Page 16 567686 V. Description of the invention (12)-Cell position, not synchronized, the code always starts its new cycle at the border of the code frame. As shown in the fifth figure, the process of processing three stages in the method 'describes the characteristics of each stage of processing. Within the first stage, a primary synchronization channel (PSCH) is used for time slot synchronization. By using the same primary synchronization channel at each search and by transmitting only the primary synchronization channel at the edge of the time slot, time slot synchronization can be easily achieved by synchronizing to the primary synchronization channel. Moreover, the generalized hierarchical Golay sequence of the generalized class system is used as the primary synchronization code because it is easy to implement. The second stage 5 2 0 has a secondary synchronization channel (SSCH) which is used to identify the frame / code after the time slot synchronization. Synchronization and code group identification can be achieved by detecting the secondary synchronization channel, where the code group is spread by one of the 16 orthogonal spreading codes, which is called the secondary synchronization code. To reduce mutual interference, the secondary synchronization code is orthogonal to the primary synchronization code. In addition, in order to achieve fast frame / code group identification, the secondary synchronization channel is further encoded into a group of 64 code words, with a (1,5,3) uninterrupted Reed-Solomon code (c 〇in ma-free Reedp Solomon code (CFRS), where each codeword of the group is represented as a soil code group. Because of the good characteristics of the interval, once the code group is specified, the synchronization of the code frame is completed. The third stage 5 3 0 has a common guidance channel (cp 丨 fjj ^ is used to determine the transmission of scrambled codes. After the code group is designated, by selecting one of the 8 codes in the two groups, the common guidance channel is used. The gastrointestinal code can be simply determined. 'The sixth diagram is a flowchart of a cell search method according to the first embodiment of the present invention, which uses the first stage sequential testing method.

567686 Five steps are listed in the fetching, invention description (13) _______ 6 0 0, to detect from one of the base stations, the incoming signal at the chip rate, the horse incoming signal. In step 6 10, it is shown as YKk), Y2 (k), and the sense sampling is insufficient, and after the oversampling, the signal signal is down-sampled and the result is output. (In step 615, the In step 6 2 0, the _1 sampling point to N parallel signal paths is performed. An optimal sampling point, in which N & processing is performed, is selected in the _oversampling point without interference, and is tied to = sampling point. The best sampling point is in the value. In the first stage of processing, the time slot with the largest sampling segment in the f sampling points is synchronized. A different% = the best sampling point is used to obtain the first order where the matched filtering The device is divided into #, # (Π〇η —coherent) matched filters, combined with their absolute values, and are divided into sections, and each-section turns out into four blocks as time slots in the first stage and As one is used at 15 o'clock, the slot system is properly fired. The accumulation of non, exceeds Γ. ·, Horse white noise (additive white

baussiannoise) 0 In order to strike from ^ u, L _, A 1 『Characteristics of the car ’s father, who is more than one time slot boundary in the first stage is chosen who λ t τ bu ^ glazed J over I f _ Stages. In the first stage of processing, select from this _ oversampling point-畀 from & Bingke Nantian 立, Li Ningjia sampling point using Nx 10 pen,). ^ It should be noted that the method used in the embodiment of the present invention is as shown in the figure. With a control process, the N oversampling points are processed in the first stage, the second stage process and the third stage process Departments have different uses. # 不二 β T is done in the middle again. In the second stage of processing, 16 matchings are used to detect the secondary synchronization code. In the second stage, in step 630, the optimal sampling point is transmitted for the second stage processing and the first stage processing. In step 64, after the time slot synchronization, the code group and code frame synchronization can be completed in the first P & segment processing. This second-stage treatment makes [Jm nr: 忐 ,, Shi Cangtu 4 people, ...

567686 V. Description of the invention (14) The coherent accumulation is estimated by using the channel from the first stage. After collecting 15 secondary sibling codes, they are related to the 6 4 comma-free Reed Solomon code (CFRS) code word, each stone horse word has 1 5 possible cycles moving position. In this way, 960 correlation values are obtained. Therefore, in the end, the code group and the cyclic position movement system regarding the maximum value are determined as reasonable code group and code frame boundaries, respectively. In step 650, the third stage of processing is to determine the scrambling code by selecting one of eight codes in a group, where the code group has been identified in the second stage. The third stage of processing determines the possible scrambling codes. Among them, a judgment is made every 256 chips, and the scrambling code corresponding to the maximum household weight is selected to be recorded. Finally, after 150 times of recording (one code) Box length), the value of the maximum number of votes must be subjected to a first verification to determine whether the scrambling code is correct. The value of the maximum number of votes is compared with a gate value 々 ^. The threshold value of 7? G is determined based on a fixed false alarm rate (connstant false r a $ e). In step 6 60, the processing result from the third stage is compared with a threshold value of 7? (Ji is compared to determine the scrambling code. If the threshold value is not exceeded, the test is considered a failure, $ One restarts without delaying f. If the threshold value of the gate is exceeded, 'the ί ΐί ίΐ. In step 670, verify the disturbance a second time. If the disturbance passes, the test becomes ί: ίί: delay When sτρ is reopened after milliseconds (ms), the selection of sampling points is 仂 e ^ 1Γ ^ α / Huibao is realized in order, and for each trial i /) × if the entire cell is searched at the Kth time Success, and the cell search time is (Κ + Ν + 1) × 10 milliseconds

Harm's Loss Is Breaking New Test Scrambling Code Is the work a success, no. Correction requires experimentation

$ 19 pages 567686 V. Description of the invention (15)

Cms) ° Please refer to the seventh chart, which is a cell search method. This method is based on the main test of the random sampling method for each test and the next test. It can help the random sampling in the existing sampling points. beneficial. As in the seventh stage of the process, its stages are explained. As shown in the seventh figure, the channel (PSCH) is used for time slot synchronization. The channel (S SC Η) is determined after the time slot synchronization. It is shown that a random sampling method per trial is used according to the second embodiment of the present invention. The idea is that N sampling points are randomly selected for detection. The motive use is shown in the appearance of the sampling frequency offset. The method also handles the three processing features which are similar to the first stage 7 1 0 of the fifth figure with a primary synchronization. The second stage 7 2 0 has secondary synchronization 'for code frame / code group identification. The third (CPICH) is the eighth figure for downloading the scrambling code. The eighth figure is a flowchart showing a cell search method according to the second embodiment of the present invention. The method uses a random sampling method per trial. Please refer to the eighth figure. In step 800, an incoming signal from the base station is detected. In step 810, the incoming signal is sampled ^ times at a chip rate, and the oversampled signal is represented as γ 乂 k), γ 2 (k),, Υν (1〇. In step 815, Down-sample the incoming signal and rotate the N oversampling points to N parallel signal paths. In step 8 2 0, randomly select a sampling point among the N oversampling points and transmit the N oversampling point. One of the sampling points was selected for the first stage treatment, the second stage treatment and the third stage treatment. It should be noted that the detection system is based on one test after another, and each sampling point is used for one test. If matched with Figure 7

567686 V. Description of the invention (16) It can clearly explain how the cell search method of the second embodiment works. For example, in the first test, in box 7 in the first stage, box 721 in the bull stage and box 73 in the third stage test the same sampling point, where the sampling point is random Select to reduce sampling frequency. -Once the test is wrong, the next new test will take the sampling point again. For example, in the second experiment, in the first stage of box 712, the second stage of box 72 2 and the third stage of box 73 ^ X will try the same selected sampling point, where the sampling point Selected randomly. Such tests will continue until the scrambling code is received by the synchronization verification process. What's more, the selection of the sampling points is realized sequentially, like the traditional catheter search method, so if the whole cell search is successful in the Kth test, the required cell search time is (K + 2) X 10 milliseconds (Ms). In step 830, the first-stage processing is synchronized with the first-time slot. A non-coherent matched filter, where the matched filter is divided into a plurality of sections, and the output of each section is combined with its absolute value, divided into four blocks and used as One is used in the first as a detector of time slot synchronization. When the non-homogeneous accumulation exceeds 5; ^ is appropriately found as additive white Gaussian noise. For better characteristics, the boundary of more than one time slot in the first stage is selected to enter the next stage. In step 8 40, after the time slot synchronization, the code group and code frame synchronization can be completed in the second stage of processing. In the second stage of processing, 6 matched filters are used to detect the secondary synchronization code. The coherent accumulative accumulation in the second phase (the coherent accumulati

567686 V. Description of the invention (17) The first order I is the channel estimation. After the collection of 15 secondary synchronization codes, they are related to 5 Hai 64 4 uninterrupted Reed-Hujin Romainma (c〇fflma — free Ree (j

Solomon code (CFRS) code words, each of which has 15 possible cyclic shift positions. In this way, 960 correlation values are obtained. Therefore, in the end, the code group and the cyclic position movement system regarding the maximum value are determined as reasonable code group and code frame boundaries, respectively. In step 850, the third stage processing determines the scrambling code by selecting one of eight codes in a group, wherein the code group has been identified in the second stage. This third stage of processing determines the possible scrambling codes, in which a judgment is made every 256 chips, and the scrambling code corresponding to the maximum value is selected to be recorded once. Finally, after 150 times of recording (one code frame length) The value of the maximum number of votes must be first verified to determine whether the scrambling code is correct. The value of the maximum number of votes is compared with a gate value of 77 G. The gate value 々D is determined based on a constant false alarm rate. In step 860, the output from the third stage processing is associated with a threshold. Compare to determine whether the scrambling code is correct. If the threshold is not exceeded, the test is considered a failure and a new test will be restarted without delay. If the value of the gate is exceeded, the scramble code is verified. In step 8 70, it is verified for the second time whether the scrambled code is nascent '. If the scrambled code passes, the test is successful, otherwise a new test is restarted after a delay time T p milliseconds (ms). Please refer to the ninth figure, which shows a cell search method according to the third embodiment of the present invention, which uses a random sampling method per yard. As shown in the ninth figure, the method also deals with a three-stage process. The characteristics of each stage of the method are similar to the explanation in the seventh figure. And the third

Page 22 567686 V. Description of the invention (18) The method of the embodiment is very similar. The examples all use random sampling strategies. The third embodiment is based on the frame, rather than the first test. Also, the method of the third embodiment uses one of the sampling points for random sampling. Please refer to Cell Search for a fine sampling method to select the sampling points on the spot. Note that the third order is Third, the sampling Y2 (k) and the code frame are incorrectly checked. At the first line of the line, they have implemented the point system of the test phase. The tenth figure below, the process of step 1020 of the method of the figure finding method, sampling points and transmitting them in one stage, the detection system is in its fairness. . In a random and independent cell search that is tested by reason, the first stage of box 931 (see Random and Independent YN (k) is selected to reduce a new test method in the second embodiment) The main difference between the two implementation methods is the selection of sampling points. The method is in a code frame followed by a code = f. The method of this example is tested in a test. That is, the method of the second embodiment is random. Sampling is one sampling point. However, each stage in the mother-in-one test is independent. It is shown that according to the third embodiment of the present invention, the method uses each code frame to randomly take f N oversampling points randomly and independently. = One of the edge N oversampling points is selected for 7-stage processing and third-stage processing. = The basic principle of a code frame followed by a code frame, and the second phase is processed. If cooperate with the first ί :: 不 — As to how the method is m can be clearly explained in block 911, the first _ purchase example, in the ninth figure) is the test of box 921 and n oversampling, where the sampling point is-tYi (k ) 'Code frames are connected, the effect of sampling frequency offset ^. # 一 者 二个 Test random iS ~~ 〜 言 言 # Release the sampling points. ^ Also

Page 23 567686 V. Description of the invention (19) That is to say, in the second test, the box 9 1 2 in the first stage, the box 9 2 2 in the second stage and the box 9 3 2 in the third stage The same selected sampling point will also be tested, where the sampling point is randomly selected. Such tests will continue until the scrambling code is accepted by the synchronization verification process. What's more, the selection of the sampling points is realized sequentially, just like the traditional catheter search method. Therefore, the right whole cell search brother succeeded in the K trials. The required cell search time is (K + 2) x 10 milliseconds (ms). The eleventh figure is a cell search architecture according to an embodiment of the present invention. The edge architecture implements the cell search method of the present invention under the effects of non-ideal sampling effects and sampling frequency offsets. A cell search device 2000 is used for the code division multiplexing access system, and more particularly it is used for the wideband code division multiplexing access system. This device handles the three-stage channels. A chip matched filter 210 is used to match an incoming signal 190 from one of the base stations. A sampling element 220 is provided for each of the soil ports 21 and 21 respectively. For oversampling the incoming signal 190 with N-sampling points (Yl (k), Y2, J rate over-sampling input sampler 23 0), connected to the sampling element, Y: (k)). ·! Drop to a first-stage detector 240 and take out the dirty three-stage detector 26. The first-stage inspection is performed again with a test result of 25 and a sampler 23, which is used to obtain the entry signal 2 and connect it to the second-stage detector 250, which is connected to the second-stage detector. Slot synchronization. One code group of the first signal 190 is synchronized with the code frame. ; = ^ 30, used to obtain the forward link to the down-sampler 2 3 0, used to determine the =, 2 = segment detector 2 6 0 ′ code. A control element 235 is connected to one of the channeling entry signals 190 to disturb. Haidi—stage detector 240, the first

567686 V. Description of the invention (20) The two-stage detector 250 and the third-stage detector 260 are used to control the N oversampling points in the first-stage detector 240 and the second-stage detector 250 and the second-stage detector 260 are used differently; and an authentication unit 2 80 is connected to the third-stage detector 260 to determine whether the test is successful. The authentication unit 2 80 further includes a comparator 2 7 0, which is connected to the third stage detector 2 60 to test the scrambling code output from the third stage and compare it with a door value Θ 0 2 71 . A first decision element 2 7 5 is connected to the comparator 2 7 0 ′ to determine whether the scrambling code is correct. A synchronous verification unit 290 is connected to the first decision element 275 to verify the scrambling code. A younger one decides the element 2 95 and is connected to the synchronous verification unit 2 90 to determine whether the scrambling code is accepted. The designer can control the control element to different embodiments of the present invention based on the effect of the non-ideal sampling effect and the effect of the sampling frequency offset. A further computer simulation is used to compare the operating characteristics of the cell search method of the embodiment of the present invention with the conventional method. The effects of undesired sampling and sampling frequency offset are emphasized here. All numerical values are based on: the oversampling point N = 2, the maximum is 4uier shift (maximuin j) 4 1ier (1 8 5 _ 2 Hz (equivalent to the user device at a speed of 100_ km / hr Movement), each stage of the detection system is 10 milliseconds (ms), τ p = 25 milliseconds (ms) and 7 ?. It is set with a 10_4 false alarm rate (connstan1; false alarm rate). In addition, the transmission power of the actual channel is shown below. First, the primary synchronization channel and the secondary synchronization channel have the same power ’, and the power ratio of the common channel and the synchronization channel (primary synchronization channel + secondary synchronization channel) is fixed. Second, of this common guiding channel

Page 567686

f: In the description of the invention (21), Christine is 10% of the total transmission power. In other words, 80% of the total transmission power of the base station during the cell search process contributes to intracellular interference. The most) is the geometry factor G = (P i + Ppsc + Pssc + PpJ / p value is used to modularize the position of the user device in the cell. A higher ^ 'indicates that the user device is closer to the user device. Near the base station. The CDF of search time is used to explore the characteristic of different search methods, which is fe. Please refer to the twelfth figure, which shows the frequency shift caused by the frequency shift according to the present invention. A signal model under the effect of sampling frequency offset. The received L number r (t) is expressed using a base-band and given as ... ', Ppsc, Cpsc, Pssc, Cssc and Ppc, Cpc is the power and spreading code of the primary synchronization channel, the secondary synchronization channel and the common guidance channel. G (t) represents the Rayleigh fading gain, which is a complex form, h (t) is a The square root of the raised cosine function (square r〇t raised cosine shaping function) has a roll-off factor (roll-0ff fact0r) of 0.22. 厶 is the chip period of the user device. Τ is the initial random delay and is Module with a random variable, the variable has the integer (-0.5Tc, 〇_5Tc) are evenly distributed. Τ selects the chip period of the base station, and Λ is the carrier frequency of the base station,

Page 26 567686 V. Description of the invention (22) The frequency offset between the platform and the user equipment, f = / a / dragon. In addition, P! And Pχ are the power of intra-ceU interferenc η i (t) and inter_ceii interference nx (t) respectively, where ⑴ and nx⑴ are white Gaussian noise (additive) white Gaussian noise) whose statistical average is zero, and the number of variations is one. Random processes are used as the type of intra- and inter-cell interference. The above model has three observation systems that are worthy of being proposed here. First, For the sake of simplicity, only flat fading channels (f lat fading) are considered, and only 9 channels searched by the cell are specifically expressed in our received signal expression; = other channels are included in the interference term n1 (t) or nx (t). Second, f is the effect of sampling frequency offset, and r is the effect of non-ideal sampling, which are ignored by the prior art. Third, = in the model The frequency offset and non-ideal sampling effects come from the propagation delay ~ (propagation del ay) uncertainty and the phase offset caused by the frequency offset, and the sampling frequency offset comes from the same oscillator source. Under the non-ideal sampling effect and the sampling frequency response f: 0kHz, compare the characteristics of different cell search methods. Among them, \ ideal is used to represent ideal sampling. As shown in the figure, non-ideal sampling causes serious damage to operating characteristics. Especially in the case of lower signal to noise ratio (SNR) (a small increase only). In this figure, all search strategies and signal to noise ratio increase ^ ^ At 6dB, a 90% chance (occasion) will be completed in 11 milliseconds. On the other hand, when the noise and gain ratio 彳 &

567686 V. Description of the Invention (23) The cell search method (STS1) of the embodiment can complete a search rate of 90% in 300 milliseconds, but it takes 450 milliseconds (ms) to the traditional search strategy. The cell search method (RSPT) of the second embodiment took 380 milliseconds (ms), and the cell search method (rspf) of the third embodiment of the present invention took more than 600 milliseconds (ms). The fourteenth graph is a comparison of the characteristics of different cell search methods under the non-ideal sampling effect and the sampling frequency offset effect A = 8 K Η z. In this case, during a test, the sampling frequency shift was almost half the chip time. If at the end of the third phase, the sampling frequency is shifted by more than one chip time, the test will never succeed. As shown in the figure, the cell search method (RSPT) of the second embodiment of the present invention and the cell search method (RSPF) of the third embodiment of the present invention have an important improvement over the conventional method. Due to the occurrence of sampling frequency offset, random sampling has a better chance to obtain more reasonable sampling points in three stages. The fifteenth figure shows the comparison of the characteristics of different cell search methods under the non-ideal sampling effect and the sampling frequency offset should be 1 2KΗζ. With the increase in the sampling frequency offset, the traditional method and the cell search method (STS1) of the first embodiment of the invention, the cell search method (RSPT) of the second embodiment of the invention, and the third embodiment of the invention The greater the difference in the operating characteristics of the cell search method (RSpF) i. It is known from FIG. 4 and FIG. 5 that the cell search method (RSP F) of the third embodiment of the present invention is a better choice when the sampling frequency is offset. Therefore, the cell search for a code division multiplexing access system according to the present invention

Page 28 567686 V. Explanation of the invention (24) Method ‘The effect of the moon soap on the code division and the fast synchronization of the initial synchronization. ^ According to the invention, according to the present invention, the cell searcher Pei Zhiyue used in the code division multiplexing access system achieves the cell frequency search effect without increasing the complexity of the hardware. It is believed that the method and device according to the present invention are applicable to mobile devices and wireless personal digital assistant (PDA) systems. f The present invention has been illustrated with the foregoing preferred embodiments, but it is not intended to limit r ^ Any person skilled in the art will not depart from the spirit and scope of the present invention.

Inside Capricorn, go to 7 仏 A and make various changes and modifications. Therefore, the protection scope of the present invention shall be defined by the scope of patent application.

567686 Simple description of the diagram [Simplified description of the diagram] Table 1 shows the sampling frequency offset generated under different frequency offset conditions. 7 The first picture is a simplified code frame structure diagram of the third-generation cooperative calculation of the day-to-day broadband / reach / division multiplexing system. The second (a) diagram shows a traditional sequential cell search method and method for the wide-spread multi-multiplexed access / frequency-division multiplexed system used in the third-generation cooperative project. (In this example, the process time of each stage is set to 丨 0 milliseconds).苐 ^ 1 (b) The picture shows the traditional wide-spreading method used in the third-generation cooperative book ^ industrial access / frequency division multiplexing system. (In this example, the process time of each stage is set to 〇0 milliseconds (^ s)). Figures 3 (a) and 3 (b) show the results of the reduction in signal level due to the effect of sampling frequency offset caused by the frequency offset and the chip-to-chip interference. The fourth diagram shows a control process using a cell searching method of the present invention. ‘No recruitment. The fifth diagram is a cell search method according to the first embodiment of the present invention, which uses the first stage sequential test (serial a stage 1 t e s t n n stage-1, STSI) method. The sixth diagram is a flowchart of a cell search method according to the first embodiment of the present invention. The method uses a first-stage sequential testing method. The seventh figure shows a cell search method according to the second embodiment of the present invention. This method uses a random sampling (r a n d 0 m s a m ρ 1 i n g p r r tria (RSPT)) method per test.

Page 567686 Brief Description of Drawings Figure 8 is a flowchart showing a cell search method according to the second embodiment of the present invention, which uses a random sampling method per test. The ninth figure shows a third cell search method according to an embodiment of the present invention. The method uses a random sampling per code frame (r n d 0 m s a m p 1 i n g p r r frame ′ RSPF) method. The tenth figure is a flowchart of a cell search method according to the third embodiment of the present invention. The method uses a random sampling method per frame. Figure IX shows a cell search architecture according to an embodiment of the present invention. This architecture implements the cell search method of the present invention. Figure 10 shows a signal model according to the present invention. The thirteenth figure is a comparison of the characteristics of different cell search methods in the presence of non-ideal sampling effects and sampling frequency offset effects-Λ = 0 kHz. The fourteenth graph is a comparison of the characteristics of different cell search methods with non-ideal sampling effects and sampling frequency offset effects Λ = 8 k Η z. The fifteenth figure shows the comparison of the characteristics of different cell search methods under the non-ideal sampling effect and the sampling frequency offset should be Λ-1 2 k Η z. [Illustration of figure number] 111 primary synchronization channel 121 secondary synchronization channel 131 common guidance channel 190 200 cell search device 210 chip matching filter 220 sampling element 230 down sampler 235 control element

567686 Schematic description 240 First-stage detector 250 Second-stage detector 260 Third-stage detector 270 Comparator 271 Gate value V 0 275 First decision element 280 Authentication unit 290 Synchronization verification unit 295 Second decision element liiil Page 32

Claims (1)

567 04 in 567686 ", with a case number of 91 dirty 7fi 6. Application scope 1. A cell search method, which uses %% as the 々t ^ in the knife-code multiplexing access system, which uses three stages of cell search # 士 4 a person T ^ only + private, this method includes the following steps: match (matc > h) the incoming signal from one of the base stations; # it ^ ^ m ^ ^ ^ # ϋ ¢ 1 # ν ^ ϋ ¢, ^ Sampling points (Y "k), Y2 (k) ,,, Y" k)); sampling w will enter # 旎 down sampling and output the N sampling points to the path; τ 1 丁 Ί 口 贶 will The N oversampling points are sequentially processed in a first stage, a second process, and a second and third stage to complete a trial (triai), where by a control process, the N oversampling points are in the first stage There are different uses in the one-stage process, the second-stage process, and the third-stage process. 2 According to the method of cell search according to the scope of the patent application, the test of the cell search brother further includes the following steps: · In the first stage of processing, one of the access signals can be synchronized with the time slot. · In the second stage In the process, it is detected that one code group of the incoming signal is synchronized with the code frame. In the third stage of processing, a scramble code of the incoming signal is selected; the scramble code and a threshold value ^^ are tested as a first authentication; If the gate value is not exceeded, the test is deemed to have failed, and a new test will be restarted without delay; otherwise, the scrambled code is selected for a second verification; wherein if the scrambled code passes the second verification , The test was successful, no Page 33 567686 Case No. 91107676 Amendment Pine 10.31 Amendment Year Λ B said to be supplemented Sixth, the scope of the patent application is a new test room TP milliseconds (ins) restarted 3. According to the cell search method of the first scope of the patent application The control process further includes the following steps: In the first-stage processing, an optimal sampling point is selected from the N oversampling points. 4. The cell search method according to item 3 of the scope of patent application, wherein the best sampling point in the N oversampling point has the largest sampling value in the N oversampling point without interference. 5. The cell searching method according to item 1 of the patent application scope, wherein the control process further includes the following steps: In the first stage of processing, a sampling point is randomly selected from the N oversampling points and transmitted to the second The stage treatment and the third stage treatment were performed in the three stages of the test. 6. The cell search method according to item 1 of the scope of patent application, wherein the control process further includes the following steps: When the first stage processing, the second stage processing and the third stage processing are performed, the system is independently A sampling point is selected from the N oversampling points to be processed at each stage of the test. 7 · Cell search method according to item 2 of the patent application scope, wherein the first stage Page 34 Segment processing further includes the following steps: In a primary synchronization channel, a generalized hierarchical Go 1 ay sequence is used as a primary synchronization code. 8. The cell search method according to item 2 of the scope of patent application, wherein the second-stage processing further includes the following steps: In the primary synchronization channel, 16 secondary synchronization codes are used, wherein the secondary synchronization code is related to the The primary synchronization code is orthogonal. 9. The cell search method according to item 8 of the scope of the patent application, wherein the secondary synchronization channel uses a (15, 3) uninterrupted Reed-Solomon code (c0mma-free Reed Solomon code, CFRS), It is further encoded into a group of 64 codewords, where each codeword of the group is represented as a code group for identifying a code frame edge and a code group. 10. The cell search method according to item 2 of the scope of the patent application, wherein the stage: stage processing further includes the following steps: ^^ After the code group is identified, the scrambled code can pass a common guidance channel, and select 8 codes One of the words. ^, 11. According to the cell search method of the 7th scope of the patent application, i-level synchronization codes select more than one or more time slot boundaries as candidates for better ^, although only one time slot boundary is correct. 567686 1 z The method of searching for the border frame fish, t,:, and cell of the code frame according to the 9th Jg stage of the scope of the patent application, where the maximum value is at the second position. The human I group is the movement of the code group and the cycle 13. According to the scope of the patent application 筮 9 ϋ 7? ^ ^ ± 1 ^ members of the cell search method, where the gate value π 0 is invited according to a fixed error 龃 u Bad rate) to decide. a report rate (constant false alarm 1 4 · according to patent application if) Chu 1 tS The search method is a cell search method used in the term, wherein the fine month is in a frequency division code multiplexed access / frequency division duplex system. ^ Cell search method for workers in patent scope No. 1 in which the fine month system. / 糸 Used in mobile devices and wireless personal digital assistants (PDA1. A cell search device to achieve three stages of cell search-chip matching filter, used for code division multiplexing access system, the device seeks, the The cell search device includes: to match an incoming letter from one of the base stations The bit-gu, envy element 'is connected to the chip-matched filter, which is used to over-sample the input 1 mouth 5 mud with a stone horse, * + / 1 X Λ Qiaoyue fan rate N times and output N over-sampled Sampling points (Yi ,: 2 (k) ,, ⑴); one drop; 1¾ 奘 is connected to the sampling element to output the N overtakes Page 36 567686 Case No. 91107B7R The phase detector, the first input signal, the first input signal, the first point to a first phase detector, a second phase detector, and a detector; connected to the down sampler for obtaining the ingress to the down sampling Device to obtain the progress; to the down-sampler to determine the first-stage detector, the second-stage detector to control the N oversampling points in the stage detector and the third Phase detector The third-stage detector is used to determine the one-stage detector of the test, and one of the time slots is synchronized; the one-stage detector, and the code group and frame are the same as the three-stage detector, and one of the incoming signals A scramble code; a control element detector and the third 'connected to the stage detector; and' connected to the first stage detector and the second to make a verification unit successful. 17. The cell search device according to item 16 of the scope of the patent application, wherein the authentication unit further includes: than the car's device is connected to the third-stage detector to test the scramble code output from the third stage With a door blocking value. Compare; a first decision element connected to the comparator to determine whether the scrambling code is correct; wherein if the gate value is not exceeded, the test is considered a failure, and a new test will be repeated without delay Initially, on the contrary, if the threshold value is exceeded, the determined scrambling code enters a synchronization verification unit; 567686 on page 37 ------------------ Car month date 6. Amendment of the scope of patent application 92 · 10 · 31 Rev. lL yyyyyyyyymmmm 4 shi added ° Hai synchronization verification unit, Connected to the first decision element for verifying the scrambled IL code; and < a first decision element connected to the synchronization verification unit for determining whether the scramble code is accepted; wherein if the scramble code passes the second decision Element, the test is successful. Otherwise, a new test restarts after a delay time of TP milliseconds (ms). The cell search device according to item 6 of the patent application scope, wherein the first stage detector is controlled by the For component control, an optimal sampling point is selected from the N oversampling points. 19. The cell searching device according to item 18 of the scope of patent application, wherein the optimal sampling point has the largest sampling value among the N oversampling points without interference. 20. The cell searching device according to item 16 of the scope of patent application, wherein the first-stage detector randomly selects one sampling point among the N oversampling points under the control of the control element, and sequentially transmits the sampling points to The second-stage detector and the third-stage detector to continue the three-stage cell search. 21. The cell search device according to item 16 of the scope of patent application, wherein the first-stage detector, the second-stage detector, and the third-stage detector are randomly and independently controlled by the control element. At the \ oversampling points Page 567686 ―Case No. 91107676 Date Amendment 6. Select a sampling point in the scope of patent application for processing in the detector at each stage. 22. The cell search device according to item 16 of the application, wherein the first detector uses a generalized hierarchical Golay sequence as a primary synchronization code in a primary synchronization channel. 2 3. The cell search device according to item 16 of the scope of patent application, wherein the second detector uses a 6 secondary synchronization codes in a secondary synchronization channel, wherein the secondary synchronization codes are synchronized with the primary The codes are orthogonal. 24. The cell search device according to item 23 of the scope of patent application, wherein the secondary synchronization channel uses a (1, 5, 3) uninterrupted Reed-Solomon code (CFRS) Is further encoded into a group of 64 codewords, where each codeword of the group is represented as a code group to identify a code frame edge and code group. 25. The cell search device according to item 16 of Yishenyan's patent, wherein after the code group is identified, the scramble code can be determined by selecting one of 8 code words through a common guidance channel. 26. The cell search device according to item 16 of the Yishen patent, wherein the first-stage detector uses a non-homogeneous synthetic matched filter to perform time slot synchronization. ZΊ According to the patent, please apply for the scope of patent No. 567686 _ kill Yu, head, 1 mouth. + February packet search device, where the brother = ^, test benefit selects more than one time slot boundary in the primary synchronization code as a better operation, although only one candidate will be considered. The cell search device, wherein the first detecting the secondary synchronization code. 28. The fine-phase detector according to item 23 of the patent application uses 16 matched filters. 29. The cell search device according to item 24 of the patent application, wherein the second-stage detector detects the code group and the loop. Let this be the boundary between the code group and the code frame. Dare man in moving position 30. According to the cell search device of the 17th scope of the patent application, the threshold value 7 / G is determined according to a fixed false alarm rate. 31. The cell searching device according to item 17 of the scope of patent application, wherein the cell searching device is used in a wideband division code multiplexed access / division duplex system. 32. The cell search device according to item 17 of the scope of patent application, wherein the cell search device is used in a mobile device and a wireless personal digital assistant PDA system.