KR100317256B1 - Frame Synchronization Method using Optimal Pilot Symbol - Google Patents

Abstract

Optimal Pilot Symbol in the Next Generation Mobile Communication System Considering Space Time Transmit Diversity (STTD) in Downlink of Especially Next Generation Mobile Communication System Using Wideband Code Division Multiple Access (W-CDMA) The present invention relates to a method of achieving frame synchronization using a pattern. In a communication system for confirming synchronization of a radio frame on a communication link using a pilot symbol pattern having a plurality of paired binary sequences, a transmission antenna diversity is used. The present invention relates to a frame synchronization method using an optimal pilot symbol in which any one of the sequence pairs of the pilot symbol pattern when transmitting a signal is replaced by a complement without applying transmit antenna diversity.

Description

Frame Synchronization Method using Optimal Pilot Symbol

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a next generation mobile communication system, and in particular, space time transmission diversity in downlink of a next generation mobile communication system using a wideband code division multiple access scheme (hereinafter, abbreviated as W-CDMA). Diversity (hereinafter, abbreviated as STTD) relates to a method of achieving frame synchronization using an optimal pilot symbol pattern.

Recently, ARIB in Japan, ETSI in Europe, T1 in the US, TTA in Korea, and TTC in Japan are the core networks of existing mobile communication globalization systems (GSMs) that provide multimedia services such as voice, video and data. The next generation of mobile communication system based on wireless access technology was envisioned.

In order to present technical specifications for the next generation evolved mobile communication system, they agreed to joint research, and the project for this was called Third Generation Partnership Project (hereinafter abbreviated as 3GPP).

3GPP includes three major technical research areas.

The first is the 3GPP system and service sector, which is a study of the structure and service capabilities of the system based on the 3GPP specification.

Second, it is a research area for Universal Terrestrial Radio Access Network (UTRAN), where the Universal Terrestrial Radio Access Network (UTRAN) is based on W-CDMA according to Frequency Division Duplex (FDD) mode. Radio Access Network (RAN) using TD-CDMA according to Time Division Duplex (TDD) mode.

Third, it is a research section for core network that has evolved from the second generation mobile communication globalization system (GSM) and has third generation networking capability such as mobility management and global roaming.

In the above-described technical research divisions of 3GPP, a research section for a global radio access network (UTRAN) describes definitions and descriptions of a transport channel and a physical channel.

Dedicated Physical Channels (DPCHs) are used for uplinks and downlinks for physical channels, which are typically Superframes, Radio frames, and Timeslots. ) Consists of three hierarchical structures.

In the 3GPP radio access network (RAN) standard, a superframe is defined in a maximum frame unit having a 720ms period, and one superframe consists of 72 radio frames in terms of the number of system frames.

A radio frame consists of 16 time slots, each time slot consisting of fields with corresponding information bits according to a dedicated physical channel (DPCH).

1 is a diagram illustrating a structure of a downlink dedicated physical channel (DPCH) according to a 3GPP radio access network (RAN) standard.

Note that the uplink dedicated physical channel (DPCH) has a fixed rate of 16 Ksps, so the number of pilot bits (or symbols) is 6 bits or 8 bits.

However, in the downlink dedicated physical channel (DPCH), since it is a variable rate, it has a pilot symbol pattern as shown in Table 1 below.

In FIG. 1, a downlink dedicated physical channel (DPCH) has two types, such as an uplink dedicated physical channel (DPCH), a dedicated physical data channel (DPDCH) and a dedicated physical control channel (DPCCH).

Of these downlink dedicated physical channels (DPCH), a dedicated physical data channel (DPDCH) is for carrying dedicated data, and the other dedicated physical control channel (DPCCH) is for carrying control information.

Dedicated Physical Control Channels (DPCCHs) that carry control information include several fields, such as transport format combining indicator field (TFCI) 10, transmit power control field (TPC) 12, and pilot field (Pilot) 14. It consists of.

Among these, the pilot field 14 includes pilot symbols that support channel estimation for coherent detection.

Table 1 shows the patterns of pilot symbols included in the downlink dedicated physical control channel (DPCCH), which are divided according to different symbol rates of the downlink dedicated physical control channel (DPCCH).

In Table 1, a pilot symbol used for downlink frame synchronization is a shaded portion of all pilot symbols at each symbol rate, and is used for frame synchronization. .

That is, for example, when the symbol rate is 16, 32, 64, 128 Ksps, symbol # 1 and symbol # 3 are used for frame synchronization. Therefore, four pilot symbols are used for frame synchronization per slot. As a result, one pilot radio frame uses 64 pilot symbols for frame synchronization.

FIG. 2 is a diagram illustrating an apparatus configuration for spreading and scramble for a downlink dedicated physical channel (DPCH) according to a 3GPP radio access network (RAN) standard.

The device configuration of FIG. 2 is a device configuration for spreading and scrambling for a downlink dedicated physical channel (DPCH) and a common control physical channel (CCPCH).

Here, quadrature phase shift keying (hereinafter, abbreviated as QPSK) is performed, and symbol pairs of two channels are serially and parallelly converted and mapped to I channel feeder and Q channel feeder, respectively.

Spreading is the process of converting all symbols through each channel feeder into multiple chips. I-channel and Q-channel feeders are spread at chip rates according to two identical channelization codes (C _Ch ), respectively. These two channel feeders are then summed and complex scrambled by C _Scramb , which is a specific complex scrambling code.

Thereafter, the real and imaginary parts are separated and transmitted on respective carriers. The different physical channels use different channelization codes, whereas the scramble code is the same code for all physical channels of one cell. Use

The downlink dedicated physical channel (DPCH), which has been spread and scrambled so far, is delivered to the receiving side to provide data and various control information.

In particular, the receiver uses a pilot symbol included in a pilot field of a received dedicated physical control channel (DPCCH) for frame synchronization.

For frame synchronization, correlation processing must be performed using pilot symbols. When performing correlation processing using downlink pilot symbols according to the 3GPP radio access network (RAN) standard shown in Table 1, an optimal frame is performed. Motivation can not be realized.

In more detail, when correlation processing is performed using the pilot symbols shown in Table 1, the correlation processing result for a radio frame having an 'N' pilot symbol in one correlation period is 'τ = 0'. It is relatively good because it has a maximum at the point and a different polarity at the point where τ = N / 2. However, there was no case where the correlation resulted in '0' at delay points other than 'τ = 0' and 'τ = N / 2', that is, in sidelobe (Sidelobe).

Therefore, it is possible to obtain correlation processing results with the same polarity and the same size at the points 'τ = 0' and 'τ = N / 2', and an optimal pilot having a minimum correlation result value in sidelobe (Sidelobe). Symbols are required, and faster and more accurate frame synchronization using these optimal pilot symbols is required.

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and provides a new pilot symbol pattern considering STTD to perform optimal frame synchronization in downlink of a next-generation mobile communication system. It is to provide a faster and more accurate frame synchronization according to the correlation processing result.

A feature of the frame synchronization method using an optimal pilot symbol according to the present invention for achieving the above object is to identify the synchronization for the radio frame on the communication link using a pilot symbol pattern having a plurality of paired binary sequences In a communication system, when transmitting a signal using transmit antenna diversity, any one of the sequence pairs of the pilot symbol pattern when transmitting the signal without using transmit antenna diversity is replaced by a complement. Preferably, the transmit diversity is characterized in that spatial or temporal block coding (STTD) is applied.

1 is a diagram illustrating a structure of a downlink dedicated physical channel (DPCH) according to a 3GPP radio access network (RAN) standard.

FIG. 2 is a diagram illustrating an apparatus configuration for spreading and scrambling for a downlink dedicated physical channel (DPCH) according to a 3GPP radio access network (RAN) standard. FIG.

3 is a block diagram showing the structure of an STTD transmitter according to the 3GPP radio access network (RAN) standard.

4 is a view for explaining the STTD encoding principle of the STTD transmitter according to the 3GPP radio access network (RAN) standard.

5 is a diagram illustrating a configuration of a correlation processing apparatus for frame synchronization using pilot symbols of a downlink dedicated physical control channel (DPCCH) according to the present invention.

6 illustrates a correlation result using a downlink pilot symbol pattern for frame synchronization according to the present invention.

FIG. 7 illustrates a structure of a primary common control physical channel (primary CCPCH) according to the 3GPP radio access network (RAN) standard. FIG.

8 illustrates a structure of a secondary common control physical channel (secondary CCPCH) according to the 3GPP radio access network (RAN) standard.

9 is a graph comparing correlation processing results of pilot symbol patterns according to the present invention;

10 is a graph showing a performance comparison by using the pilot symbol pattern of the present invention.

* Description of symbols on the main parts of the drawings *

20: channel encoder 21: rate matching

22: interleaver 23: first multiplexer

24: STTD encoder 25: second multiplexer

26: first transmission antenna (T _X Antenna 1) 27: second transmission antenna (T _X Antenna 2)

Hereinafter, a preferred embodiment of a frame synchronization method using an optimal pilot symbol according to the present invention will be described with reference to the accompanying drawings.

The 3GPP radio access network (RAN) specification refers to transmit diversity of downlink physical channels. Open loop transmit diversity and closed loop transmit diversity are applied on different downlink physical channels.

In this case, STTD based on spatial or temporal block coding is used for open loop transmit diversity.

In the present invention, a new pilot pattern for downlink is proposed in consideration of the STTD, and a frame synchronization procedure using the proposed new pilot pattern will be described.

In particular, the present invention describes a frame synchronization procedure using the pilot pattern of the present invention in a downlink dedicated physical channel (Downlink DPCH) and a common control physical channel (CCPCH).

3 is a block diagram showing the structure of an STTD transmitter according to the 3GPP radio access network (RAN) standard.

Referring to FIG. 3, the STTD transmitter shown is for open loop transmit diversity.

The data input to the STTD transmitter is first subjected to the following blocks in the non-diversity mode. The channel coding and the rate matching unit 21 by the channel encoder 20 are performed. Rate matching and interleaving by the interleaver 22 are performed and then input to the first multiplexer 23.

The first multiplexer 23 multiplexes the final interleaved data, transmission format combining indicator bits (TFCI) and transmission power control bits (TPC).

The STTD encoder 24 outputs data patterns to be transmitted through the first transmission antenna 26 and the second transmission antenna 27 to the second multiplexer 25 using the principle illustrated in FIG. 4 below. . Again, the second multiplexer (25) includes a symbol (S1, S2) by the QPSK is input also generated to have their symbols (S1, S2) and the orthogonality symbol (-S2 ^*, S1 ^*) is that this type.

FIG. 4 is a diagram illustrating a STTD encoding principle of an STTD transmitter according to a 3GPP radio access network (RAN) standard.

As an example of the STTD encoding principle with reference to FIG. 4, first, the QPSK symbol input to the STTD encoder 24 is 'S1 = 1 1' in the first symbol interval (0 to T), and the second symbol interval (T to Let's say 'S2 = 1 0' in 2T).

At this time, the symbols generated so as to be orthogonal to these QPSK symbols in the STTD encoder 24 are respectively '0 0' in the first symbol interval (0 to T) and '1 0' in the second symbol interval (T to 2T). Becomes

The symbols generated by the STTD encoding principle have the following characteristics.

The symbol '0 0' generated in the first symbol interval (0 to T) is a conversion of the QPSK symbol S2 of the second symbol interval (T to 2T) input to the STTD encoder 24, and the second symbol interval The symbol '1 0' generated at (T-2T) converts the QPSK symbol S1 of the first symbol section 0-T input to the STTD encoder 24.

In short, the symbol '-S2 ^* , S1 ^* ' is generated in each symbol period through the shifting, maintenance, and conversion process according to the STTD encoding principle.

As a result, the correlation value of these symbols '-S2 ^* , S1 ^* = 0 0, 1 0' and the QPSK symbol (S1, S2 = 1 1, 1 0) input to the STTD encoder 24 becomes '0', Has orthogonality.

In addition, the pilot multiplexer 25 receives a pilot symbol pattern shown in Table 2 below and a pilot symbol pattern (Table 4) having orthogonality to the pilot symbol channel shown in Table 2 below.

Since the data pattern inputted from the STTD encoder 24 to the second multiplexer 25 takes into account STTD, the pilot symbol patterns shown in Table 4 are also generated by applying the pilot symbol patterns of Table 2 to the STTD encoding principle. .

First, Table 2 shows various channel information about a downlink dedicated physical control channel (DPCCH) and a downlink dedicated physical data channel (DPDCH).

Channel Bit Rate (Kbps) Channel symbol rate (Ksps) Spread-ing Factor Bits per frame Bits per slot (bits / slots) Bits per Slot in DPDCH (bits / slots) Bits per Slot in DPCCH (bits / slots) DPDCH DPCCH Sum N _data1 N _data2 N _TFCI N _TPC N _pilot 16 8 512 64 96 160 10 2 2 0 2 4 16 8 512 32 128 160 10 0 2 2 2 4 32 16 256 160 160 320 20 2 8 0 2 8 32 16 256 128 192 320 20 0 8 2 2 8 64 32 128 480 160 640 40 6 24 0 2 8 64 32 128 448 192 640 40 4 24 2 2 8 128 64 64 960 320 1280 80 4 56 8 ^* 4 8 256 128 32 2240 320 2560 160 20 120 8 ^* 4 8 512 256 16 4608 512 5120 320 48 240 8 ^* 8 16 1024 512 8 9728 512 10240 640 112 496 8 ^* 8 16 2048 1024 4 19968 512 20480 1280 240 1008 8 ^* 8 16

Table 3 shows a pattern of pilot symbols included in the downlink dedicated physical control channel (DPCCH), and is divided according to different symbol rates of the downlink dedicated physical control channel (DPCCH).

In the above-mentioned Table 3, the pilot symbols used for downlink frame synchronization are used for frame synchronization only in the shaded part of all pilot symbols at each symbol rate, and pilot symbols in other parts except this have a value of '1'. Have

That is, in the case where the symbol rate is 16, 32, 64, 128 Ksps (N _Pilot = 8), for example, symbol # 1 and symbol # 3 are used for frame synchronization, and therefore, pilot used for frame synchronization per slot. Since there are four symbols, 64 pilot symbols (4x16) are used for frame synchronization in one radio frame.

Table 4 below shows patterns of pilot symbols included in the downlink dedicated physical control channel (DPCCH) according to different symbol rates. When the symbol rate is 8ksps, the I channel of the first pilot symbol (symbol # 1) is shown. The column sequence mapped to the tributary is C1, the column sequence mapped to the Q-channel tributary is C2, and the I of the first pilot symbol (symbol # 1) when the symbol rate is 16,32,64,128ksps (N _Pilot = 8) Column sequence mapped with channel feeder C1, column sequence mapped with channel feeder C2, column sequence mapped with channel I tributary of the third pilot symbol (symbol # 3) Column sequence mapped with channel feeder C3 and Q channel Is called C4.

Finally, when the symbol rate is 256,512,1024ksps, each I-channel feeder or each Q-channel feeder of the first, third, fifth, and seventh pilot symbols (symbol # 1, symbol # 3, symbol # 5, symbol # 7) The vertical sequence mapped to is called C1, C2, C3, C4, C5, C6, C7, and C8.

Symbol rate Pilot symbol location number (symbol #) Channel feeder Column Sequence 8ksps (N _Pilot = 4) One I C1 Q C2 16,32,64,128ksps (N _Pilot = 8) One I C1 Q C2 3 I C3 Q C4 256,512,1024ksps (N _Pilot = 16) One I C1 Q C2 3 I C3 Q C4 5 I C5 Q C6 7 I C7 Q C8

The following lists the sequences for downlink frame synchronization when the symbol rate is 256,512,1024 Ksps (N _Pilot = 8).

Such sequences of the downlink dedicated physical control channel (DPCCH) for frame synchronization newly proposed in the present invention are ( , It is made on the principle of).

That is, 8 bits on all sides ( ) First, then the rear 8 bits ( ) Is the complement of 8 bits of the front side.

The final result of performing correlation processing for frame synchronization using these sequences is '128 0 0 0 0 0 0 0 -128 0 0 0 0 0 0 0'.

Table 5 shows the pilot symbol patterns included in the downlink dedicated physical control channel (DPCCH), and converts the pilot symbol patterns of Table 3 in consideration of STTD.

Symbol rate Pilot symbol location number (symbol #) Channel feeder Column Sequence 8ksps (N _Pilot = 4) 0 I Q C2 16,32,64,128ksps (N _Pilot = 8) One I Q C4 3 I C1 Q 256,512,1024ksps (N _Pilot = 16) One I Q C4 3 I C1 Q 5 I Q C8 7 I C5 Q

In Table 6, pilot symbol patterns considering STTD are classified according to different symbol rates, and the following sequence sequences are obtained based on the column sequence defined in Table 4.

When the symbol rate is 8ksps (N _Pilot = 4), the parallel sequence mapped to the I-channel tributary in the first pilot symbol (symbol # 0) is 1's complement to C1. The column sequence mapped to the Q channel tributary is C2.

When the symbol rate is 16,32,64,128ksps (N _Pilot = 8), the column sequence mapped to the I-channel tributary in the first pilot symbol (symbol # 1) is 1's complement to C3. , The sequence sequence mapped to the Q-channel tributary is C4, the column sequence mapped to the I-channel tributary in the third pilot symbol (symbol # 3) is C1, and the serial sequence mapped to the Q-channel tributary is 1's complement to C2. to be.

Finally, when the symbol rate is 256,512,1024ksps (N _Pilot = 16), each I channel of the first, third, fifth, and seventh pilot symbols (symbol # 1, symbol # 3, symbol # 5, symbol # 7) A triangular sequence that maps to a tributary or each Q-channel tributary in order , C4, C1, , , C8, C5, to be.

In Table 5, when the symbol rate is 256,512,1024 Ksps (N _Pilot = 16), the sequences for downlink frame synchronization are listed.

This is also the same as the column sequence in Table 3 ( , It is made on the principle of). 8-bit front side ) First, and the trailing 8 bits ( ) Is the complement of 8 bits of the front side.

The final result of performing correlation processing for frame synchronization using these sequences is the same as the final result correlated using the column sequence shown in Table 3 '128 0 0 0 0 0 0 0 -128 0 0 0 0 0 0 0 ' to be.

5 is a diagram illustrating a configuration of a correlation processing apparatus for frame synchronization using pilot symbols of a downlink dedicated physical control channel (DPCCH) according to the present invention.

The apparatus for processing downlink correlation shown in FIG. 5 includes 16,32,64,128 Ksps (N _Pilot = 8) in the pilot symbol pattern included in the downlink dedicated physical control channel (DPCCH) shown in Tables 3 and 5 below. An example of using a symbol rate pilot sequence is shown.

Here, the unit of the symbol rate is 'Ksps = (symbol × 10 ³ ) / second'.

In the present invention, as in the 3GPP radio access network (RAN) standard, the pilot symbol used for the frame synchronization of the downlink is that only the shaded portion of all pilot symbols of each symbol rate is used for frame synchronization. The pilot symbol has a value of '1'.

That is, in the case where the symbol rate is 16, 32, 64, 128 Ksps (N _Pilot = 8), for example, symbol # 1 and symbol # 3 are used for frame synchronization, and therefore, pilot used for frame synchronization per slot. Since there are four symbols, 64 radio symbols (4x16) are used for frame synchronization in one radio frame.

The correlation process using the pilot symbol pattern according to the present invention described above exhibits the characteristics as shown in FIG. 6, which will be described in more detail below.

In addition, the present invention further proposes a pilot symbol pattern of a new common control physical channel (CCPCH) to be used for correlation processing for frame synchronization.

FIG. 7 is a diagram illustrating a structure of a primary common control physical channel (PCCPCH) according to 3GPP radio access network (RAN) standard.

The primary common control physical channel (PCCPCH) is a downlink physical channel used to carry a broadcast channel (BCH). It is a fixed rate of 32 Ksps and uses a 256 spreading factor (SF). do.

As shown in FIG. 7, the primary common control physical channel (PCCPCH) does not transmit a transmission format combining indicator bit (TFCI) or a transmission power control bit (TPC), unlike the downlink dedicated physical channel (DPCH). Only control information transmits only 8 bits of common pilot bits required for correlation detection.

In addition, the primary common control physical channel (PCCPCH) has no transmission during the initial 256-chip period of each slot, and instead, the primary SCH and the secondary SCH are transmitted during this period. .

Table 7 below shows a pattern of pilot symbols for frame synchronization on a primary common control physical channel (PCCPCH).

Table 8 below is a pilot pattern considering STTD when using open loop transmission diversity, and is generated by applying the pilot symbol pattern of Table 7 to the STTD encoding principle.

In particular, in the primary common control physical channel (PCCPCH), only data symbols are STTD encoded, and accordingly, a pilot symbol pattern considering STTD is shown in Table 8.

8 is a diagram illustrating a structure of a secondary common control physical channel (SCCPCH: secondary CCPCH) according to the 3GPP radio access network (RAN) standard.

The secondary common control physical channel (SCCPCH) is a channel used to carry a forward access channel (FACH) and a calling channel (PCH), and includes a transport format combining indicator bit (TFCI). And two forms that do not include it.

The Transport Format Combination Indicator field (TFCI) is a field for supporting multiple services at the same time. If the Transport Format Combination Indicator bit (TFCI) is not included, it means that it is a fixed-rate service. do.

Since the secondary common control physical channel (SCCPCH) shown in FIG. 8 may or may not include a transport format combining indicator bit (TFCI), a variable rate such as the downlink dedicated physical channel (DPCH) described above is variable. Rate or Fixed Rate are available.

Table 9 below shows various channel information for the secondary common control physical channel (SCCPCH).

Channel bit rate (Kbps) Channel Symbol Rate (Ksps) Spread-ing Factor Bits per frame Bits per slot (bits / slots) Number of data bits (N _data ) Number of pilot bits (N _pilot ) Transport Format Coupling Indicator Bits (N _TFCI ) 32 16 256 320 20 12 8 0 32 16 256 320 20 10 8 2 64 32 128 640 40 32 8 0 64 32 128 640 40 30 8 2 128 64 64 1280 80 72 8 0 128 64 64 1280 80 64 8 8 256 128 32 2560 160 152 8 0 256 128 32 2560 160 144 8 8 512 256 16 5120 320 304 16 0 512 256 16 5120 320 296 16 8 1024 512 8 10240 640 624 16 0 1024 512 8 10240 640 616 16 8 2048 1024 4 20480 1280 1264 16 0 2048 1024 4 20480 1280 1256 16 8

Table 10 below shows pilot symbol patterns for frame synchronization on a secondary common control physical channel (SCCPCH).

In Table 11, when four column sequences of length 16 are mapped to the I-channel and Q-channel branches of each pilot symbol position number (symbol #), these column sequences are referred to as C1, C2, C3, and C4. .

Pilot symbol location number (symbol #) Channel feeder Column Sequence One I C1 Q C2 3 I C3 Q C4

Table 12 below considers STTD, and is generated by applying the pilot symbol patterns of Table 10 to the STTD encoding principle.

This is a pilot pattern considering STTD when using open loop transmit diversity.

As such, the final result of performing correlation processing for frame synchronization using the pilot symbol pattern of the common control physical channel (CCPCH) considering STTD is the same as the correlation result in the dedicated physical channel (DPCH) of the downlink described above. Show characteristics.

That is, the same characteristics as shown in FIG.

Hereinafter, each pilot symbol pattern of the downlink dedicated physical channel (Downlink DPCH) and the common control physical channel (CCPCH) described so far will be synthesized, and a procedure for achieving frame synchronization using the pilot pattern of the present invention will be described.

Table 13 summarizes the column sequences C1 to C8 that are the basis for the pilot symbol patterns of the downlink dedicated physical channel (Downlink DPCH) and the common control physical channel (CCPCH) described above. The primary correlation treatment results are also shown simultaneously.

Column sequence Correlation results [r _x (1) to r _x (16)] C1 = (1101111100100000) 16 4 0 4 0 -4 0 -4 -16 -4 0 -4 0 4 0 4 C2 = (1000101001110101) 16 -4 0 -4 0 4 0 4 -16 4 0 4 0 -4 0 -4 C3 = (1101110000100011) 16 4 0 -4 0 4 0 -4 -16 -4 0 4 0 -4 0 4 C4 = (0111011010001001) 16 -4 0 4 0 -4 0 4 -16 4 0 -4 0 4 0 -4 C5 = (1011000001001111) 16 4 0 4 0 -4 0 -4 -16 -4 0 -4 0 4 0 4 C6 = (1110010100011010) 16 -4 0 -4 0 4 0 4 -16 4 0 4 0 -4 0 -4 C7 = (0100001110111100) 16 4 0 -4 0 4 0 -4 -16 -4 0 4 0 -4 0 4 C8 = (1110100100010110) 16 -4 0 4 0 -4 0 4 -16 4 0 -4 0 4 0 -4

Table 13 shows the following four classes (E, F, G, and H) for each column sequence where the first order correlation result (at points A ₁ , A ₂ , A ₃ , and A ₄ of FIG. 5) is the same. Can be divided into

E = {C1, C5}, F = {C2, C6}, G = {C3, C7}, H = {C4, C8)

R (τ) ＼ τ 0 One 2 3 4 5 6 7 8 9 10 11 12 13 14 15 R _E (τ) 16 4 0 4 0 -4 0 -4 -16 -4 0 -4 0 4 0 4 R _F (τ) 16 -4 0 -4 0 4 0 4 -16 4 0 4 0 -4 0 -4 R _G (τ) 16 4 0 -4 0 4 0 -4 -16 -4 0 4 0 -4 0 4 R _H (τ) 16 -4 0 4 0 -4 0 4 -16 4 0 -4 0 4 0 -4

Table 14 shows the correlation result value 'R (τ)' for each class described above.

Based on the values shown in Table 14, some of the following correlation results can be derived.

, (Where τ is even)

, (Where τ is odd)

, (For all τ)

The following formula 4 can be obtained from the above formulas 1, 2 and 3 above.

In Table 14 and Equation 4, respectively And As can be seen, the result of the second order correlation processing (at point A in FIG. 5) for the radio frame has the maximum value 'R (τ) = 32' at the point 'τ = 0' and 'τ = N / At the point 2 ', the polarities are reversed and have the same maximum value' R (τ) = -32 '. In addition, the correlation processing result is '0' at the delay points other than the 'τ = 0' and 'τ = N / 2' points, that is, the side lobe (Sidelobe).

In addition, in the present invention, the following derived expressions can be obtained from the proposed pilot pattern for frame synchronization.

here, Is a correlation result value using the column sequences C1 to C8.

In addition, the following resultant expressions can be obtained from the equations listed above.

Therefore, the final correlation processing result (at point B of FIG. 5) for the radio frame according to Equation 6 has the maximum value 'R (τ) = 64' at the point 'τ = 0' and 'τ = N / 2' At the point at, the polarities are reversed and have the same maximum value 'R (τ) = -64'. In addition, the correlation processing result is '0' at delay points other than 'τ = 0' and 'τ = N / 2', that is, sidelobe (Sidelobe).

As a result, when the correlation processing procedure for frame synchronization is performed using the pilot pattern proposed in the present invention, two frame synchronizations can be checked at every correlation period for one frame during frame synchronization. Will be.

9 is a graph comparing correlation processing results of pilot symbol patterns according to the present invention.

FIG. 9A shows the results of secondary correlation processing (at point A in FIG. 5) for a downlink dedicated physical control channel (DPCCH) with a symbol rate of 8 Ksps (N _Pilot = 4) in the current 3GPP Radio Access Network (RAN) specification. This is a comparison of performance and correlation results.

As can be seen in FIG. 9A, the correlation result has a positive maximum value and a negative maximum value at a point where delay is '0' and '8', and in other side lobes, a correlation result is obtained. You can see that it is '0'.

FIG. 9B shows the final correlation processing result for the downlink dedicated physical control channel (DPCCH) and the secondary common control physical channel (SCCPCH) with a symbol rate of 16, 32, 64, 128 Ksps (N _Pilot = 8) (B of FIG. 5). Point) is a performance comparison with the correlation processing results according to the current 3GPP Radio Access Network (RAN) specification, and FIG. 9C shows a downlink dedicated physical control channel (DPCCH) with a symbol rate of 256,512,1024 Ksps (N _Pilot = 16). The final correlation processing result is compared with the correlation processing result according to the current 3GPP Radio Access Network (RAN) standard.

9, the correlation result shows the maximum value of the polarity different from each other at the point where the delay is '0' and '8', and the correlation result is '0' in the other side lobes.

The following is a frame synchronization procedure in downlink according to the present invention.

On the UE side, the UE acquires chip synchronization and frame synchronization of the downlink channel based on the synchronization timing, the frame offset group and the slot offset group of the primary common control physical channel (PCCPCH).

In this case, for synchronization acquisition, frame synchronization is checked using the pilot symbol pattern proposed by the present invention.

The frame synchronization procedure of the downlink channel will be described in more detail. First, the UE (UE) first confirms chip failure and acquires frame synchronization by initial chip synchronization.

At this time, the UE uses the timing of the primary common control physical channel (PCCPCH) and also uses the frame offset information and the slot offset information informed by the network. The frame offset group and the slot offset group are received.

When the frame synchronization based on chip synchronization is initially acquired, the UE (UE) checks the obtained frame synchronization using the pilot symbol pattern proposed by the present invention.

That is, the user side UE continuously checks whether or not the frame synchronization is shifted in accordance with the correlation result value of the pilot symbol pattern.

In this case, if the chip synchronization is acquired but the frame synchronization is misaligned, in the present invention, when the frame synchronization is misaligned, the chip synchronization failure is confirmed again to achieve the final chip synchronization and the frame synchronization.

10 is a graph illustrating a performance comparison by using the pilot symbol pattern of the present invention.

10A illustrates frame synchronization detection probability for a downlink dedicated physical control channel (DPCCH) of 8 Ksps (N _Pilot = 4) symbol rate over the AWGN channel.

FIG. 10B illustrates a probability of malfunction in frame synchronization detection for a downlink dedicated physical control channel (DPCCH) of 8 Ksps (N _Pilot = 4) symbol rate over the AWGN channel.

FIG. 10C illustrates the frame synchronization confirmation probability for the downlink dedicated physical control channel (DPCCH) of 8 Ksps (N _Pilot = 4) symbol rate over the AWGN channel.

As described above, in the present invention, the following effects can be obtained.

First, by using the optimal pilot symbol newly proposed in the present invention, it is possible to double check the synchronization in order to achieve frame synchronization, thereby realizing accurate frame synchronization. This can reduce the seek time for synchronization.

Second, if the optimal pilot symbol newly proposed in the present invention is used, the correlation processing apparatus on the receiving side for frame synchronization can be configured more simply, thereby reducing the overall complexity of the receiving apparatus.

Third, when frame synchronization fails in the frame synchronization procedure of the present invention, it is possible to actively cope with this, and thus more accurate frame synchronization is possible.

Claims (8)

In a communication system for confirming synchronization for a radio frame on a communication link using a pilot symbol pattern having a plurality of paired binary sequences, When transmitting a signal using transmit antenna diversity, an optimal pilot symbol is applied by substituting any one of the sequence pairs of the pilot symbol pattern for a signal transmission without using transmit antenna diversity as a complement. Frame synchronization method. 2. The method of claim 1, wherein the transmit diversity is spatial or temporal block coding (STTD) applied. The method of claim 1, wherein the sequence of the first sequence pair and the second sequence pair is changed when there are four sequences constituting the plurality of pairs. 10. The method of claim 9, wherein when selecting a sequence replaced by a complement in one sequence pair, the sequence is different from a sequence replaced by a complement in another sequence pair. The frame synchronization using the optimal pilot symbol according to claim 1, wherein the signal not using the transmit antenna diversity is transmitted through a first antenna, and the signal using the transmit antenna diversity is transmitted through a second antenna. Way. The optimal pilot symbol according to claim 1, wherein each pilot sequence has a maximum correlation value at a point matched in a correlation period and a maximum correlation value having a different sign at a middle point of the correlation period. Frame sync method. The method of claim 12, wherein the pilot sequence is a sequence in which all values of 0 and 1 are the same number. 14. The frame synchronization method according to claim 13, wherein the pilot sequence is a sequence obtained by complementing a sequence of the first half.