WO2007121682A1 - Procédé et appareil de reconnaissance de cellules pour système cellulaire ofdma - Google Patents

Procédé et appareil de reconnaissance de cellules pour système cellulaire ofdma Download PDF

Info

Publication number
WO2007121682A1
WO2007121682A1 PCT/CN2007/001368 CN2007001368W WO2007121682A1 WO 2007121682 A1 WO2007121682 A1 WO 2007121682A1 CN 2007001368 W CN2007001368 W CN 2007001368W WO 2007121682 A1 WO2007121682 A1 WO 2007121682A1
Authority
WO
WIPO (PCT)
Prior art keywords
cell
frequency domain
synchronization channel
large number
sequence
Prior art date
Application number
PCT/CN2007/001368
Other languages
English (en)
Chinese (zh)
Inventor
Ming Ding
Hanwen Luo
Ji Zhang
Tingwei Zhang
Yun Wu
Haibin Zhang
Li Sun
Wei Guan
Feng She
Original Assignee
Shanghai Jiao Tong University
Sharp Kabushiki Kaisha
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from CNB2006100259863A external-priority patent/CN100466800C/zh
Priority claimed from CNB2006100283129A external-priority patent/CN100512255C/zh
Priority claimed from CNB2006101175687A external-priority patent/CN100486128C/zh
Application filed by Shanghai Jiao Tong University, Sharp Kabushiki Kaisha filed Critical Shanghai Jiao Tong University
Publication of WO2007121682A1 publication Critical patent/WO2007121682A1/fr

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/0001—Arrangements for dividing the transmission path
    • H04L5/0003—Two-dimensional division
    • H04L5/0005—Time-frequency
    • H04L5/0007—Time-frequency the frequencies being orthogonal, e.g. OFDM(A), DMT

Definitions

  • the present invention relates to a cell identification method in the field of communication technology, and in particular to a cell identification method applied to an 0FDMA (Orthogonal Frequency Division Multiple Access Multiple Access) cellular system.
  • 0FDMA Orthogonal Frequency Division Multiple Access Multiple Access
  • OFDM Orthogonal Frequency Division Multiplexing
  • 3GPP 3rd Generation Mobile Communications Partnership
  • EUTRA Evolved Universal Mobile Telecommunications System and Land-Based Radio Access
  • EUTRAN Evolved Universal Mobile Telecommunications System Network and Land-Based Radio
  • Super 3G Super 3G mobile communication system
  • n "natural numbers greater than or equal to 4" OFDM symbols as synchronization channel symbols in each frame, and load a special sequence in the frequency domain.
  • Each frequency domain sequence corresponds to one codeword
  • a specific combination of codewords corresponds to a group of cell numbers (or a group of cell scrambling code numbers), common to; c c cell number groups, and then obtains a cell number by a CPICH (Common Pilot Channel) similar to WCDMA (or For the cell scrambling code number), common; c, the cell number.
  • CPICH Common Pilot Channel
  • the method (1) has the characteristics of simple synchronization channel structure, but has the disadvantage of a small number of cell identifications.
  • Methods (2) and (3) have the disadvantages of high computational complexity and large symbol overhead of the synchronization channel. Therefore, the above three methods encounter great difficulties in practical applications. Summary of the invention
  • the object of the present invention is to provide a cell identification method applied to an 0FDMA cellular system in the prior art that the computational complexity is high, the synchronization channel symbol overhead is large, or the number of cell identifications is small.
  • the present invention only needs one OFDM symbol in each frame as the synchronization channel data, by loading data on the subcarriers of different mode patterns, distinguishing different cell large numbers, and then passing the frequency on the adjacent loaded data subcarriers.
  • the domain difference sequence distinguishes different cell small numbers, and finally the cell is jointly identified by the cell large number and the cell small number to achieve the purpose of identifying a large number of cells, while keeping the present invention low in computational complexity.
  • a cell identification method for an OFDM A cellular system comprising the following steps:
  • the transmitting end generates an OFDM synchronous channel symbol including a cell large number and a cell small number information, and is larger than each cell.
  • the number corresponds to a mode pattern of loading data on the loadable subcarrier, and corresponding to each cell small number is a frequency domain difference sequence loaded on the adjacent enabled subcarrier; when the receiving end performs the received synchronization channel symbol Frequency transform to obtain a frequency domain sequence of synchronization channel symbols; identifying an energy sequence pattern of the received loadable subcarriers, obtaining a cell large number; and identifying The cell small number is obtained by using a differential frequency domain sequence loaded on the subcarrier.
  • a cell identification apparatus applied to an OFDM A cellular system, comprising: means for generating an OFDM synchronization channel symbol including a cell large number and cell small number information, corresponding to each cell large number
  • the mode pattern of loading data on the loadable subcarriers, corresponding to the small number of each cell is to load the frequency domain difference sequence on the adjacent enabled subcarriers; obtaining the synchronization channel by time-frequency transforming the synchronization channel symbols Means for identifying a frequency domain sequence of symbols; means for identifying a received energy sequence pattern of the loadable subcarriers to obtain a cell large number; and means for identifying a differential frequency domain sequence loaded on the enabled subcarriers to obtain a cell small number.
  • a cell identification method for an OFDM A cellular system comprising the steps of: generating, by a transmitting end, an OFDM synchronization channel symbol including a cell large number and cell small number information, corresponding to each cell large number
  • the mode pattern of loading data on the payload subcarrier, corresponding to the small number of each cell is to load the frequency domain difference sequence on the adjacent enabled subcarriers; the receiving end performs time-frequency transform on the received synchronization channel symbols.
  • a cell identification apparatus for an OFDM cellular system comprising: means for generating an OFDM synchronization channel symbol including a cell large number and cell small number information, corresponding to each cell large number A mode pattern of loading data on the payload subcarrier, corresponding to each cell small number, loading a frequency domain difference sequence on the adjacent enabled subcarriers; obtaining a synchronization channel symbol by performing time-frequency transform on the received synchronization channel symbols a device for frequency domain sequence; a device for calculating a probability metric of a large cell number of each cell by performing energy detection on a frequency domain synchronization channel symbol; calculating a large number in each of the cells by differential demodulation and frequency domain sequence detection Under the condition of the number, the current cell adopts a measure of the possibility of the small number of each cell; the possibility measure of the large number of each cell, and the condition of the small number of each cell under the condition of the large number of each cell Sexual metrics, normalized and multiplied to obtain the large
  • a cell identification method for an OFDM cellular system comprising the steps of: generating, by a transmitting end, an OFDM synchronization channel symbol including a cell large number and cell small number information, corresponding to each cell large number It is a mode pattern that can load data on the loaded subcarriers, and corresponding to each cell small number is a frequency domain difference sequence loaded on the adjacent enabled subcarriers; synchronization is performed by time-frequency transforming the received synchronization channel symbols.
  • Frequency domain sequence of channel symbols energy detection of frequency domain synchronization channel symbols; differential demodulation and frequency domain sequence detection of frequency domain synchronization channel symbols; frequency domain energy detection result and frequency domain of combined synchronization channel symbols according to L criterion
  • the sequence detection result looking for the peak value, makes an optimal joint estimation of the cell large number and the cell small number.
  • a cell identification apparatus for an OFDM cellular system comprising: means for generating an OFDM synchronization channel symbol including a cell large number and cell small number information, corresponding to each cell large number
  • a mode pattern for loading data on a loaded subcarrier, corresponding to each cell small number is to load a frequency domain difference sequence on an adjacent enabled subcarrier; and obtaining a synchronization channel symbol by performing time-frequency transform on the received synchronization channel symbol a device for frequency domain sequence; a device for performing energy detection on a frequency domain synchronization channel symbol; a device for differentially demodulating and frequency domain sequence detection of a frequency domain synchronization channel symbol; and frequency domain energy detection for combining synchronization channel symbols according to ML criterion
  • the result and the frequency domain sequence detection result finding a peak, and means for making an optimal joint estimation of the cell large number and the cell small number.
  • the identification method firstly loads data on subcarriers of different mode patterns, distinguishes different cell large numbers, and then loads different frequency domain difference sequences on adjacent loaded data subcarriers to distinguish different cell small numbers, and finally The cell is jointly identified by the cell large number and the cell small number to achieve the purpose of identifying a large number of cells while keeping the present invention low in computational complexity.
  • the range of the search cell can be narrowed, thereby reducing the computational complexity of the present invention.
  • an algorithm for jointly estimating the cell large number and the cell small number is proposed, so that the present invention has a relatively slim The cell identifies the correct rate.
  • Figure 1 shows the OFDM baseband modulation and demodulation block diagram.
  • FIG. 2 is a block diagram of a first embodiment of the present invention
  • FIG. 3 is a cyclic autocorrelation function diagram of d s
  • Figure 5 is a typical situation diagram
  • Figure 6 is a typical diagram of ⁇
  • Figure 7 is the positional relationship between the receiver and three neighboring cells.
  • FIG. 8 is a graph showing the correct rate of cell identification using the first multi-symbol decision method in the method according to the first embodiment of the present invention and the Motorola scheme in the case of multi-cell.
  • FIG. 9 is a graph showing the correct rate of cell identification using the second multi-symbol decision method in the method according to the first embodiment of the present invention and the Motorola method in the case of multi-cell.
  • Figure 10 is a block diagram showing the implementation of the second embodiment of the present invention.
  • FIG. 11 is a view (g) of FIG. 12 is a typical case of I 3 is Pr (g,?)
  • 21 is a block diagram of an implementation of a third embodiment of the present invention.
  • FIG. 22 is a typical case diagram of /? (g).
  • FIG. 23 is a typical case diagram.
  • FIG. 24 is a typical case diagram of ⁇ , ).
  • 0FDM is a multi-carrier modulation system.
  • Each subcarrier can carry QAM symbols or PSK symbols.
  • the modulation and demodulation process can be represented by IDFT (Inverse Discrete Fourier Transform) and DFT (Discrete Fourier Transform).
  • IDFT Inverse Discrete Fourier Transform
  • DFT Discrete Fourier Transform
  • the subcarrier sequence number is defined as follows:
  • the receiving end determines the current cell large number g by performing a correlation search on the received energy subcarriers (see correlation peaks). It can be seen that the data loading mode pattern can be loaded through the loadable subcarriers. Different cell numbers.
  • the identifiable number of cell large numbers C s is also an adjustable parameter.
  • 31 8 out of 8
  • 31 8 out of 8
  • Different frequency domain differential data sequences are used in different cells of the same cell to distinguish different Small cell number.
  • a cell that defines a cell with a large number g ( i ⁇ g ⁇ ) it must have a payload subcarrier and a subcarrier Sf ⁇ that does load data in the payload subcarrier, which is collectively referred to as an enabled subcarrier S,
  • C frequency-domain difference sequences p 9 ⁇ p"(i) ⁇ (1 ⁇ ? ⁇ ⁇ , 1 ⁇ / ⁇ Z)) (for example, PN sequence or GCL (Generalized chirp-like) The sequence, etc.) is used to distinguish the small cell numbers.
  • the cell size is g, the cell with the cell size number g is selected to be loaded and g 2 (the corresponding subcarrier corresponding to 0)
  • 0 is an arbitrary random phase, indicating that the data on the partially enabled subcarrier is not constrained by g and g, and can be used to improve the PAPR (peak-to-average power ratio) of the synchronization channel symbol.
  • frame synchronization and frequency synchronization of OFDM is a relatively mature technology. For example, select 0 (mod L) ⁇ (13) Then, without loading data on the subcarriers of S ⁇ S..., it is possible to generate Z-divided OFDM synchronization channel symbols and calculate the specific delay autocorrelation of the synchronization channel symbols in the time domain. Find the peak value to determine the starting position of the frame, and then find the phase angle of the peak to estimate the frequency deviation. See the literature: T. Keller, L. Piazzo,
  • a fixed frequency domain sequence is loaded on a part of subcarriers in s ⁇ s... to generate a fixed time domain sequence, which is known in advance for both the transmitting end and the receiving end, and is used by the receiving end.
  • This time-domain sequence performs a continuous correlation search on the received signal.
  • the position of the correlation peak is the starting position of the 0FDM symbol.
  • the phase characteristics of the received sequence are examined, and the frequency deviation is estimated.
  • 3GPP, Rl-060781, NTT DoCoMo "Cell Search Time Performance of Three-Step Cell Search Method”.
  • H t is the multipath fading channel for the t-th subcarrier
  • M't is the frequency domain additive noise of the channel to the first subcarrier
  • the domain difference sequence obtain the cell small number 9 according to the previous stage, obtain the sum S ⁇ from the equations (6) and (7), and then obtain the S ⁇ from the equation (8), and then examine all the S according to the equation (9). 4 , and the length of the frequency domain difference sequence is obtained by the equation (10), and then, according to the equation (11), the set S of adjacent subcarrier pairs is determined.
  • Equation (21) requires Z) submultiple multiplication
  • equation (22) requires DxC complex multiplication and ( ⁇ -1) ⁇ complex addition, which is calculated in equation (23).
  • the method of the first embodiment of the present invention can recognize a total of In the same cell, in order to complete the cell identification task more reliably, a multi-symbol decision algorithm can be used, that is, multiple synchronization channel symbols are examined, and different decision strategies are used to perform cell identification, thereby obtaining a larger reliable cell than a single decision. Number and cell small number decision value.
  • Method 1 Investigate f/synchronous channel symbols. For each synchronization channel symbol, obtain the U cell big number estimation values ( ⁇ x ⁇ U) according to equations (18) and (19), and then make a majority decision. , ie: g - arg ⁇ count ( (x), g) ⁇ x ⁇ U, ⁇ g ⁇ C g ⁇ (24) where nt( ⁇ c), g) denotes the number of elements equal to g . When there are more than two values, it is necessary to additionally examine one sync channel symbol until it appears unique. Let's use a total of ⁇ /' sync channel symbols to get unique. According to , for each synchronization channel symbol, calculate equations (21) and (22), get 7 ⁇ ) (1 ⁇ ⁇ ⁇ ⁇ /), square merge 7; then, use equation (25) to get the cell small number estimated value
  • Method 2 Investigate C7 synchronization channel symbols. For each synchronization channel symbol, calculate ⁇ (g) (l ⁇ x ⁇ t/) according to equation (18), and then add ⁇ (g):
  • Equation (26) is equivalent to (f/- 1) /2 times. Then, it is obtained according to the formula (19). According to the calculation of equation (21) and equation (22) for each synchronization channel symbol, 7( )(l ⁇ ; c ⁇ C/) is obtained, and the square is merged 7; (after that, the cell small number is obtained by using equation (25). The estimated value of ⁇ .
  • the total number of complex multiplications required for method 2 is ⁇ ((:(8. ⁇ personally) + £> + £>> ⁇ (: + € ), the number of additions is [/ ⁇ ( 0 ⁇ 2 + ( - l)xC ) + (i7- 1) ⁇ 2.
  • the method according to the first embodiment of the present invention can identify up to 31 cell large numbers under the above physical layer conditions, and the cyclic autocorrelation function of any d s is as shown in FIG. 3 .
  • S a g c , as follows:
  • the method of the first embodiment of the present invention is identifiable in total
  • the receiving end enters the cell identification process according to FIG. 2.
  • the receiving end performs frame synchronization and frequency synchronization according to FIG. 2 (S111).
  • the received data passes through the receive filter processing module 8, the A/D conversion module 9, and the synchronization unit module 15 of FIG. Since the generated synchronization channel symbol has the characteristics of 2 divisions, the receiving end calculates the half-symbol delay autocorrelation of the synchronization channel symbol in the time domain, finds the peak value to determine the starting position of the frame, and estimates the phase angle of the peak. Frequency deviation. According to the result of frame synchronization and frequency synchronization, the synchronization channel symbols are correspondingly compensated (S112).
  • the received data passes through the extracted synchronization channel symbol module 10 of FIG.
  • the receiving end starts the identification of the cell large number according to FIG. 2.
  • this step requires 16 complex multiplications and 248 complex additions.
  • Equation (22) can be effectively implemented by a 17-point FFT. First, w' (0) is complemented by a zero, and then 17 points FFT:
  • T ⁇ q) ⁇ W()exp -j2 ⁇ .£ ⁇ -, (1 ⁇ 16) (31)
  • the receiving end uses the combination of ⁇ as the final cell identification result according to Figure 2.
  • Method 1 Investigate t/synchronous channel symbols. For each synchronization channel symbol, obtain the estimated values of U cell large numbers O) ( ⁇ x ⁇ U) according to equations (18) and (19), and then according to the formula ( 24) Estimate the large cell number ⁇ , and then use equation (25) to obtain an estimate of the cell small number. The combination of and is the result of cell identification.
  • Method 2 Investigate the synchronization channel symbols. For each synchronization channel symbol, calculate 1 ( (1 ⁇ ⁇ ) according to equation (18), and then combine according to equation (26) (and then according to equation (19) The number is estimated ⁇ , and then the estimated value of the cell small number is obtained by the equation (25). The combination of the sum is the result of the cell identification.
  • the simulation channel is 6-ray GSM Typical Urban Channel (Global Mobile Communication Typical Urban Area 6-Channel Channel, referred to as 6-ray TU).
  • the parameters are as follows:
  • the worst case is considered, that is, the receiving end is located at an equidistant position from the three neighboring cells, as shown in FIG. 7, and it is considered that the synchronization channel signal is sent from three cells, and after different 6 - After the ray TU, it arrives at the receiving end at the same time, wherein the g and g of the three cells are different.
  • the receiving power of one of the three cells (the cell big number is G and the cell small number is ⁇ ) is the strongest. This is the target access cell, and the other two cells have the same received power, which is regarded as the signal of the interfering cell.
  • the ratio of the signal received power of the target access cell to the signal received power of the two interfering cells is SIR (signal-to-interference ratio), on which the white noise is superimposed, and the power of the white Gaussian noise is compared with the standard access.
  • the signal reception power of the cell is OdB.
  • Figure 8 is a diagram showing the method of the first embodiment of the present invention and the solution of Motorola in the case of a multi-cell A cell identification correct rate performance graph using the first multi-symbol decision method.
  • the method of the first embodiment of the present invention and the scheme of Motorola use the cell identification correct rate performance map of the second multi-symbol decision method.
  • the simulation results show that the present embodiment has the advantages of large number of identified cells, low computational complexity, and low estimation error rate, and has high application value in OFDM systems.
  • the first embodiment of the present invention has the advantages that: only one OFDM symbol is needed as synchronization channel data in each frame, which has the advantage of low synchronization channel data overhead, and the peak-to-average power ratio of the symbol is low, and cascading is adopted.
  • the cell identification method firstly loads data on subcarriers of different mode patterns, distinguishes different cell large numbers, and then loads different frequency domain difference sequences on adjacent loaded data subcarriers to distinguish different cell small numbers. Finally, the cell is jointly identified by the cell large number and the cell small number to achieve the purpose of identifying a large number of cells, and at the same time, the implementation complexity is kept low.
  • the second embodiment of the present invention is different from the first embodiment in that the large number is preselected by the possibility measure of the cell large number, and the large number and the small number are jointly estimated.
  • R(g) is a measure of the likelihood that the current cell adopts the large number of each cell.
  • the current cell is sorted by the probability metric of each cell's large number, and the first A large number is used as the cell preselected large number, which is recorded as a set.
  • G k pre ⁇ g I g is the first I element after sorting from large to small ⁇ (l ⁇ A ⁇ C g ) (33) where, the larger the ⁇ , the better the performance of the present embodiment, but the calculation The higher the complexity.
  • A is a parameter in the system design, determined by the time allocated by the system to the cell search, hardware resources, and the like.
  • T ⁇ (q) is the probability metric of the current cell using the small number of each cell under the condition that each cell pre-selects a large number.
  • geG pre l ⁇ q ⁇ C ( (39)
  • fs(g) is used as the cell in the current cell size under the condition that the cell size is g.
  • the conditional probability of number 9 is reasonable. The greater the correlation, the greater the probability. Obviously, for all g, the probability normalization condition is met. -
  • the method of the second embodiment of the present invention can identify a total of C 7 f different cells.
  • a multi-symbol decision algorithm can be used, that is, multiple synchronization channel symbols are examined.
  • merge decision methods cell identification is performed, thereby obtaining a cell big number and a cell small number decision value that are more reliable than a single decision.
  • Method 1 Inspect [/ synchronization channel symbols, for the Xth synchronization channel symbol, obtain ⁇ (g) according to equation (32), sort it according to equation (33) to get G A p ⁇ , and then by equation (36) ⁇ ), then get (g) and () according to equations (37) and (39), and then according to formula (41), obtain the probability Pr of the current cell combination of various cell large numbers and cell small numbers, (g, ⁇ , addition merges Pr, (g, ⁇ ?), get -
  • Equation (36) is obtained by ( ⁇ ), first for ⁇ (g) and
  • both methods 1 and 2 need to be calculated and), but method 1 needs to calculate (g) and H (9), and its product Pr g, in each synchronization channel symbol, and method 2 After observing [/ synchronization channel symbols, we calculate (g) and), and their products Therefore, method one requires approximately ([/ - 1) A(2C + 1) real multiplications than method two.
  • the degree of difficulty of implementation since the numerical range of ⁇ (g), f(g), and Pr g in the first method is strictly limited to [0, 1], the numerical range of the calculation result is known. So it is easy to implement with devices such as fixed-point DSP. However, the numerical values of ⁇ (g) and r ( ⁇ ) involved in the second method are large, and are easily affected by the finite precision effect when implemented.
  • the receiving end starts the cell identification process according to the steps listed in FIG. 10, firstly calculating the probability metric of the current cell adopting the large number of each cell as g. According to formula (32),
  • the probability g) that the current cell adopts the cell preselected large number g is obtained.
  • the normalization operation is performed to obtain the conditional probability fg( ) of the current cell using the cell small number of 9 under the condition that the cell preselected large number is g.
  • the cell large number 19
  • the typical case of q) is shown in Fig. 12.
  • the typical case of Pr(g, is shown in Fig. 13.
  • the probability maximum is found according to equation (42), and joint estimation of the cell size is described.
  • Method 1 Inspect ⁇ /synchronous channel symbols. For the Xth sync channel symbol, obtain (g) according to equation (32), sort it by G according to equation (33), and then obtain it by equation (36). Then according to the formula
  • Method 2 Investigate t/synchronous channel symbols. For the Xth sync channel symbol, obtain (g) according to equation (32), sort it by G( ⁇ ) according to equation (33), and then obtain equation (36). (g), first (g) Combine with (?), and then use (37) and (39) to get (g) and Then, P r (g, ) is obtained from the equation (41), and a joint estimate is made on the sum of g and the equation (42).
  • the emulation channel is 6-ray GSM Typical Urban Channel (Global Mobile Telecommunications Typical Urban Area 6-Channel Channel, referred to as 6-ray TU), with the following parameters:
  • the worst case is considered, that is, the receiving end is located at an equidistant position from the three neighboring cells, as shown in FIG. 7, and it is considered that the synchronization channel signal is sent from three cells, and after different 6 - After the ray TU, it arrives at the receiving end at the same time, wherein the g and g of the three cells are different.
  • the received power of one of the three cells (the cell big number is G and the cell small number is ⁇ ) is the strongest. This is the target access cell, and the other two cells have the same received power, which is regarded as the signal of the interfering cell.
  • the ratio of the signal received power of the target access cell to the signal received power of the two interfering cells is SIR (signal-to-interference ratio), on which the white noise is superimposed, and the power of the white noise is compared with the standard access.
  • the signal reception power of the cell is OdB.
  • Performance in the case of 90% cell identification correct rate
  • the performance difference between the non-joint algorithm (the first embodiment of the present invention) and the second method is gradually reduced to 0.5 dB)
  • the main calculation amount of the first embodiment is the moduli square operation of the equation (32), and the difference sequence calculation of the equation (34), which is about 31 complex multiplications in total, and a 17-point FFT. Therefore, the computational complexity of the present invention using the non-joined algorithm (first embodiment) and the Motorola scheme is approximately equal.
  • the computational complexity of the joint algorithm (the first method and the second method) in this embodiment is about 1 times the complexity described above. In order to reduce the complexity of using the joint algorithm, a smaller I can be selected.
  • the joint estimation algorithm (the first method and the second method) of the present invention improves the performance of the present invention, so that the present invention acquires the number of supporting cells more than 14 times (496/36) than the Motorola solution. Almost the same cell recognition performance. Therefore, the method of the second embodiment of the present invention has the advantages of large number of identified cells, high estimation accuracy, and low computational complexity, and has a very high application value in the OFDM system.
  • the second embodiment of the present invention has the advantages that: only one OFDM symbol is needed as synchronization channel data in each frame, which has the advantage of low synchronization channel data overhead, and the peak-to-average power of the symbol is relatively low; cascading cell identification is adopted.
  • the method firstly loads data on subcarriers of different mode patterns, distinguishes different cell large numbers, and then loads different frequency domain difference sequences on adjacent loaded data subcarriers to distinguish different cell small numbers, which are total
  • the number of identifiable cells is the product of the number of cell large numbers and the number of cell small numbers, which enables the present invention to support a large number of cell systems; in addition, by selecting an appropriate cell large number preselected number I, the search cell can be narrowed down.
  • the scope of the invention reduces the computational complexity of the present invention.
  • an algorithm for jointly estimating the cell large number and the cell small number is proposed, so that the present invention has a higher cell recognition correct rate.
  • the third embodiment of the present invention is different from the first embodiment in that the cell large number is preselected, and then the ML criterion is used to perform optimal joint estimation of the small cell number and the cell small number.
  • processing (2) of the third embodiment is the same as the processing (2) of the first embodiment, it will not be described in detail herein.
  • G x pre ⁇ g I g ? ( ⁇ The first i elements after sorting from large to small ⁇ (l ⁇ A ⁇ C g ) (51) where, the larger A is, the better the performance of the present invention is, but The computational complexity is higher.
  • equation (51) is equivalent to not pre-selecting the cell large number, that is, global search for the cell large number, and the performance of the present invention is optimal at this time. It is a parameter in the system design, determined by the time allocated by the system to the cell search, hardware resources, and so on.
  • the optimal joint estimation of the cell large number and the cell small number is derived according to the ML criterion, and the estimated metric values of the cell large number and the cell small number are deduced, and the received signal is first assumed. From equation (17), to ⁇ fl (and / do hypothesis ⁇ and . Among them,
  • the cell identification metric based on the ML criterion, the metric value is equal to the sum of the frequency domain energy detection result of the corresponding ⁇ ) and the real part of the frequency domain sequence detection result of 2 times, searching for the peak value thereof, thereby Optimal joint estimation of large numbers and small cell numbers:
  • the method of the third embodiment of the present invention can identify a total of C S C different cells.
  • a multi-symbol decision algorithm can be used, that is, multiple synchronization channel symbols are examined.
  • cell identification is performed, thereby obtaining a cell big number and a cell small number decision value that are more reliable than a single decision.
  • G may not be the same, so the value of g in equation (62) is .
  • the estimation performance of the present invention is significantly improved.
  • the main computational amount of the method of the third embodiment of the present invention is concentrated in the frequency domain energy detection of equation (50) and the frequency domain sequence detection of equation (54), which respectively require about 8 ⁇ .
  • the receiving end starts the cell identification process according to the steps listed in Fig. 21, firstly performing energy detection on the frequency domain synchronization channel symbol.
  • FIG. 24 A typical case of ⁇ ( ⁇ ) is shown in Fig. 24.
  • Equation (61) For the Xth sync channel symbol, get (g) according to equation (63), sort it by G according to equation (51), and then get ( ) from equation (64). Equations (63) and (64) are substituted into equation (60), ( ⁇ ), and then ⁇ ( , ) is obtained according to equation (62). Finally, the optimal joint estimation of g and 9 is obtained by equation (61).
  • the simulation channel is 6-ray GSM Typical Urban Channel (Global Mobile Communication Typical Urban Area 6-Channel Channel, referred to as 6-ray TU), and its parameters are as follows:
  • the worst case is considered, that is, the receiving end is located at an equidistant position from the three neighboring cells, as shown in FIG. 7, and it is considered that the synchronization channel signal is sent from three cells, and after different 6 After the -ray TU arrives at the receiving end at the same time, the g sums of the three cells are different.
  • the receiving power of one of the three cells (the cell big number is G and the cell small number is 2) is the strongest. This is the target access cell, and the other two cells have the same received power, which is regarded as the signal of the interfering cell.
  • the ratio of the signal received power of the target access cell to the signal received power of the two interfering cells is SIR (signal-to-interference ratio), on which the Gaussian white noise is superimposed, and the power of the white noise is compared with the standard access.
  • the signal reception power of the cell is OdB.
  • the figure examines the case of t/-1, 3, 5.
  • Equations (65) and (66) are expressions directly estimated by the present invention. Note that the formula (65) is the same as the formula (19) of the first embodiment, and the formula (66) is the same as the formula (46) of the second embodiment.
  • the optimal estimation algorithm based on the ML criterion proposed by the third embodiment of the present invention has good estimation performance, so that the implementation manner is obtained under the premise that the number of supported cells is greater than 14 times (496/36) of the Motorola solution. Better than its cell recognition performance. Therefore, the present embodiment has the advantages of large number of identified cells, high estimation accuracy, and low computational complexity, and has high application value in the 0FDMA system.
  • the third embodiment of the present invention has the advantages that: only one OFDM symbol is needed as synchronization channel data in each frame, which has the advantage of low synchronization channel data overhead, and the peak-to-average power of the symbol is relatively low; cascading cell identification is adopted.
  • the method firstly loads data on subcarriers of different mode patterns, distinguishes different cell large numbers, and then loads different frequency domain difference sequences on adjacent loaded data subcarriers to distinguish different cell small numbers, which are total
  • the number of identifiable cells is the product of the number of cell large numbers and the number of cell small numbers, which enables the present embodiment to support a large number of cell systems; in addition, selecting a suitable cell large number preselected number can narrow the search cell.
  • the scope of the invention reduces the computational complexity of the present invention.
  • an optimal algorithm for estimating the cell large number and the cell small number is proposed, so that the present embodiment has a higher cell recognition correct rate.

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Mobile Radio Communication Systems (AREA)

Abstract

L'invention concerne un procédé de reconnaissance de cellules utilisé dans un système cellulaire OFDMA, appartenant à la technique de communication. Chaque trame ne requiert qu'une seule marque OFDM comme données de canaux de signaux synchrones, d'où les avantages associés à ces données de canaux de signaux synchrones, tels qu'une faible consommation, la valeur de puissance moyenne maximale de la marque étant faible. En outre, le procédé consiste à utiliser la reconnaissance de cellules en cascade, à utiliser le modèle modal de différentes ondes sous-porteuses chargées en données afin de reconnaître des groupes de différents nombres de cellules, et à utiliser la séquence de différences de fréquence d'une onde sous-porteuse voisine chargée en données afin de reconnaître les différents nombres de cellules, ce qui permet de reconnaître un nombre important de cellules. L'invention fait appel à une détermination multi-marques pour améliorer la capacité d'estimation. Cette invention se caractérise avantageusement par un nombre important de cellules reconnues, une faible complexité de calcul, un faible taux d'erreur et une haute valeur d'application dans un système OFDMA.
PCT/CN2007/001368 2006-04-24 2007-04-24 Procédé et appareil de reconnaissance de cellules pour système cellulaire ofdma WO2007121682A1 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
CNB2006100259863A CN100466800C (zh) 2006-04-24 2006-04-24 一种应用于ofdma蜂窝系统的小区识别的方法
CN200610025986.3 2006-04-24
CNB2006100283129A CN100512255C (zh) 2006-06-29 2006-06-29 Ofdma蜂窝系统的小区识别方法
CN200610028312.9 2006-06-29
CN200610117568.7 2006-10-26
CNB2006101175687A CN100486128C (zh) 2006-10-26 2006-10-26 Ofdma蜂窝系统的小区识别方法

Publications (1)

Publication Number Publication Date
WO2007121682A1 true WO2007121682A1 (fr) 2007-11-01

Family

ID=38624559

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2007/001368 WO2007121682A1 (fr) 2006-04-24 2007-04-24 Procédé et appareil de reconnaissance de cellules pour système cellulaire ofdma

Country Status (1)

Country Link
WO (1) WO2007121682A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120000071A1 (en) * 2009-03-19 2012-01-05 Technip France Offshore wind turbine installation system and method

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1691659A (zh) * 2004-04-23 2005-11-02 北京三星通信技术研究有限公司 在正交频分复用系统中用于同步的方法
EP1610514A1 (fr) * 2004-06-25 2005-12-28 Samsung Electronics Co., Ltd. Procédé et dispositif pour la génération d'un signal pilote avec l'identification de la cellule dans un système OFDM
US20060028976A1 (en) * 2004-07-02 2006-02-09 Samsung Electronics Co., Ltd. Apparatus and method for transmitting/receiving pilot signal in communication system using OFDM scheme
WO2006023536A2 (fr) * 2004-08-16 2006-03-02 Zte San Diego, Inc. Recherche cellulaire rapide et synchronisation exacte dans des communications sans fil

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1691659A (zh) * 2004-04-23 2005-11-02 北京三星通信技术研究有限公司 在正交频分复用系统中用于同步的方法
EP1610514A1 (fr) * 2004-06-25 2005-12-28 Samsung Electronics Co., Ltd. Procédé et dispositif pour la génération d'un signal pilote avec l'identification de la cellule dans un système OFDM
US20060028976A1 (en) * 2004-07-02 2006-02-09 Samsung Electronics Co., Ltd. Apparatus and method for transmitting/receiving pilot signal in communication system using OFDM scheme
WO2006023536A2 (fr) * 2004-08-16 2006-03-02 Zte San Diego, Inc. Recherche cellulaire rapide et synchronisation exacte dans des communications sans fil

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120000071A1 (en) * 2009-03-19 2012-01-05 Technip France Offshore wind turbine installation system and method

Similar Documents

Publication Publication Date Title
US9232486B2 (en) Method and apparatus for transmitting synchronization signals in an OFDM based cellular communications system
US7738437B2 (en) Physical layer structures and initial access schemes in an unsynchronized communication network
KR100715913B1 (ko) 직교주파수분할다중접속 방식의 이동통신시스템에서레인징 신호 검색 장치 및 방법
Tsai et al. Cell search in 3GPP long term evolution systems
CN102148785B (zh) 一种lte系统中主同步信号检测与序列生成方法及装置
EP2696524B1 (fr) Dispositif de station mobile
US7386055B2 (en) Multi-carrier transmission/reception apparatus
CA2674274C (fr) Sequences de synchronisation secondaires pour la detection de groupes de cellules dans un systeme de communication cellulaire
EP1745628B1 (fr) Methode et appareil pour detecter une cellule dans un systeme d'acces a multiplexage frequentiel optique orthogonal
KR100802844B1 (ko) 직교주파수분할다중접속 시스템의 레인징 채널 처리 장치및 방법
JP2005506757A (ja) マルチ搬送波ｃｄｍａシステムにおける同期化
JPWO2003032541A1 (ja) Ｏｆｄｍ受信方法及びｏｆｄｍ受信装置
US20050135230A1 (en) Apparatus and method for processing ranging channel in orthogonal frequency division multiple access system
KR101110312B1 (ko) 주파수 옵셋 추정 장치 및 방법
Kim et al. Sequence hopping cell search scheme for OFDM cellular systems
CN101534137A (zh) 用于解调控制信号的设备和方法
CN100493064C (zh) 基于虚拟子载波和频域差分序列的估计ofdm整数频偏的方法
WO2007121682A1 (fr) Procédé et appareil de reconnaissance de cellules pour système cellulaire ofdma
CN100512255C (zh) Ofdma蜂窝系统的小区识别方法
CN100466800C (zh) 一种应用于ofdma蜂窝系统的小区识别的方法
Bartis et al. Achieving secondary synchronization for downlink in the long term evolution standard
CN100486128C (zh) Ofdma蜂窝系统的小区识别方法
KR101449865B1 (ko) Ｏｆｄｍ 시스템에서의 초기 동기화 방법 및 그 장치
Chang et al. A low-complexity algorithm for cell identity detection in NB-ioT physical layer
Shukur et al. Implementing primary synchronization channel in mobile cell selection 4G LTE-A network

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 07720941

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 07720941

Country of ref document: EP

Kind code of ref document: A1