KR101625385B1 - Radio transmitter and receiver for transmitting in ultra-narrow bandwidth - Google Patents

Abstract

The present invention relates to radio transmission and reception units for transmission in an ultra-narrow band. The radio transmission unit for transmission in an ultra-narrow band according to an embodiment of the present invention comprises: a CRC encoder which performs CRC-encoding on a protocol data unit; a scrambler which scrambles the CRC-encoded protocol data unit; a convolutional encoder which convolutionally encodes the CRC-encoded, scrambled protocol data unit; a channel interleaver which performs channel-interleaving on a signal received from the convolutional encoder; a symbol mapping unit which maps the signal, received from the channel interleaver, to a specific symbol; an RRC filter which limits a band of the signal to an ultra-narrow band; and an interpolation filter unit which performs interpolation.

Description

TECHNICAL FIELD [0001] The present invention relates to a radio transmitter and receiver for transmitting an ultra-

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transceiver unit and a receiver unit for ultra-narrow band transmission.

In recent years, digital radios have been widely used in public offices, industrial sites, and digital radios using VHF / UHF frequencies.

Also, in recent years, various researches are underway to efficiently use limited frequency resources.

Korean Patent Registration No. 10-0937851 (Jan. 13, 2010) discloses a multi-carrier radio communication apparatus using a multi-carrier, wherein a spurious component of a multi-carrier generated due to nonlinear characteristics of a power amplifier The present invention relates to a high speed data communication radio having a multicarrier allocation function and a method thereof capable of reallocating a frequency of a multi carrier so as to prevent spreading out of a frequency band, An RF unit for performing down-conversion and up-conversion of multi-carriers for each channel for high-speed data communication and performing transmission and reception of RF signals, and a multi-carrier unit for multi-carriers for high-speed data communication amplified by the RF unit, A spurious wave measuring unit for measuring a spurious wave band, And a control unit for controlling the spurious wave measuring unit to receive the spurious wave band values generated in the respective channel-by-channel multi-carriers, and then, when the spurious waves of the respective multi-carriers do not overlap with the multi- And a controller for reallocating the frequency of the multi-carriers for each channel within the used frequency band so as to have an interval.

The present invention proposes a transmitter and a receiver of a transceiver for efficiently transmitting data in an ultra-wide band.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a radio transmitter and receiver for a high bandwidth transmission rate.

The transceiver transmitter for transmitting the ultra wide band according to an embodiment of the present invention includes a CRC encoder for performing CRC encoding of the protocol data unit, a scrambler for scrambling the CRC encoded protocol data unit, the CRC encoding, the scrambled protocol data unit A channel interleaver for performing channel interleaving on a signal received from the convolutional encoder; a symbol mapping unit for mapping the signal received from the channel interleaver to a specific symbol; An RRC filter, and an interpolation filter unit for performing interpolation.

According to an embodiment of the present invention, a transceiver transmission unit for transmitting a control channel further includes a transmission control unit for generating a control frame if data is control data and controlling generation of an actual data frame if the data is real data.

The interpolation filter unit includes a first interpolation filter and a second interpolation filter, wherein the first interpolation filter has an interpolation rate twice that of the second interpolation filter.

And the scrambler initializes the scrambler register with a user ID in the same case as the actual data message.

A radio receiver for downlink transmission according to an exemplary embodiment of the present invention includes a reception filter unit for performing downsampling, a frame / symbol synchronization unit for performing frame synchronization and symbol synchronization, a frequency / And a Viterbi decoder, wherein the Viterbi decoder comprises a branch metric calculator, a path metric memory, an add-compare memory, and an adder, and wherein the Viterbi decoder comprises: Select, and survivor pass memory.

According to the embodiment of the present invention, the radio transmitting unit and the receiving unit for the ultra-narrow band transmission have the following effects.

First, the present invention can increase the data rate by paralleling a plurality of modulation schemes.

Second, the present invention has an effect of increasing the transmission efficiency by generating and transmitting a frame by applying a modulation scheme and a coding rate differently according to the kind of data to be generated (for example, control signal (control data), actual data) .

Third, the present invention can enhance the signal quality by transmitting a signal by limiting the band to a specific ultra wide band.

1 is a view for explaining a frame according to an embodiment of the present invention.
2 is a view for explaining a preamble region according to an embodiment of the present invention.
FIG. 3 illustrates a transceiver unit for transmitting an ultra high bandwidth according to an embodiment of the present invention. Referring to FIG.
FIG. 4 illustrates a transceiver receiver for ultra-narrow band transmission according to an embodiment of the present invention. Referring to FIG.
5 illustrates a time synchronization unit according to an embodiment of the present invention.
6 illustrates a channel equalizer in accordance with an embodiment of the present invention.
7 illustrates a Viterbi decoder according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. However, it is to be understood that the present invention is not limited to the disclosed embodiments, but may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. It is intended that the disclosure of the present invention be limited only by the terms of the appended claims.

Also, terms used herein are for the purpose of illustrating embodiments and are not intended to limit the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. &Quot; comprises "and / or" comprising "used in the specification do not exclude the presence or addition of components other than the components mentioned. Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the present invention, the control unit controls the transceiver. For convenience of explanation, the control unit of the transmission unit is divided into a transmission control unit and a control unit of the reception unit. The control unit is a transmission control unit when a signal is transmitted, It becomes a reception control section.

1 is a view for explaining a frame according to an embodiment of the present invention.

In the present invention, a frame means a specific type of signal for transmitting data (information), and the term can be used variously.

FIG. 1 (a) is a control frame according to an embodiment of the present invention, and FIG. 1 (b) is an actual data transmission frame according to an embodiment of the present invention.

The present invention proposes a frame for applying a high-efficiency modulation scheme (for example, QPSK, 16QAM, 64QAM) to transmit high-speed data within an ultra-wideband (e.g., 6.25 kHz). Here, high-speed data can be digital Land Mobile Radio (LMR) high-speed data.

Referring to FIG. 1 (a), a control frame is used to transmit a call control message, an Ad-hoc radio link setup message, and the like.

A control frame is a frame for transmitting a control signal (control data), and includes a preamble area, a pilot area, and a data area. Here, the control frame includes at least one pilot region and at least one data region in one preamble region.

For example, the control frame includes 64 symbols in the preamble area for 12.8 ms, and includes 3 symbols in one data area, and 320 symbols including all pilot areas and all data areas for 64 ms (symbols).

Referring to Fig. 1 (b), the actual data frame is used to transmit actual data such as the voice of the application layer (APP-layer).

The actual data frame is a frame for transmitting actual data such as voice, and includes a preamble area, a pilot area, and a data area. Here, the actual data frame includes at least one pilot region and at least one data region in one preamble region.

For example, the actual data frame includes 32 symbols in the preamble region for 6.4 ms, and includes 7 symbols in one data region, including all pilot regions and all data regions for 70.4 ms. 352 symbols.

The reason why the control frame is configured differently from the actual data frame is to further increase the probability of receiving important control signals while transmitting data in the ultra wide band.

As described above, the frame (control frame, actual data frame) according to the present invention is designed to provide frame synchronization, symbol synchronization, and frequency synchronization in the transceiver receiver, and allocates pilot symbols for wireless channel estimation of the transceiver receiver. QAM data symbols for transmission are arranged.

Table 1 below shows an example of AMC (Adaptive Modulation and Coding) according to a high efficiency modulation scheme and a coding rate applied to a control frame.

AMC Data Length Coding Rate Modulation Info Rate (kbps) 0 240 0.5 QPSK 3.75 One 480 0.5 16QAM 7.50 2 720 0.5 64QAM 11.25

Table 2 shows an example of Adaptive Modulation and Coding (AMC) according to a high efficiency modulation scheme and a coding rate applied to an actual data frame.

AMC Data Length Coding Rate Modulation Info Rate (kbps) 0 446 0.75 QPSK 7.22 One 600 One QPSK 9.63 2 908 0.75 16QAM 14.44 3 1216 One 16QAM 19.25 4 1370 0.75 64QAM 21.66 5 1832 One 64QAM 28.88

As described above, according to the present invention, a frame is generated by applying a modulation scheme and a coding rate differently according to a type of data to be generated (for example, a control signal (control data), actual data) have.

2 is a view for explaining a preamble region according to an embodiment of the present invention.

FIG. 2 (a) is a view for explaining a preamble region in a control frame according to an embodiment of the present invention, and FIG. 2 (b) is a diagram for explaining a preamble region in an actual data frame according to an embodiment of the present invention. The drawing

Referring to FIG. 2 (a), the preamble area in the control frame is composed of 64 symbols. Here, the 64 symbols include an AGC 6 symbol, a first synchronization sequence 27 symbol, a second synchronization sequence 27 symbol, and a guard 4 symbol.

At this time, the AGC symbol is a symbol transmitted by the RF AGC of the transceiver part to converge to an appropriate level.

로 정의될 수 있으며, 각 원소는 아래 수학식 1과 같다.
The synchronization sequence comprising the first synchronization sequence and the second synchronization sequence

And each element is represented by the following equation (1).

That is, the control frame transmits the synchronization sequence by concatenating the first synchronization sequence (k = 3 in Equation 1) and the second synchronization sequence (k = 5 in Equation 1).

Referring to FIG. 2 (b), the preamble region in the actual data frame is composed of 32 symbols. Here, the 32 symbols include AGC 4 symbols, one synchronization sequence 27 symbols, and Guard 1 symbols.

That is, the actual data frame is transmitted by applying one synchronization sequence (k = 1 in Equation (1)).

FIG. 3 illustrates a transceiver unit for transmitting an ultra high bandwidth according to an embodiment of the present invention. Referring to FIG.

Referring to FIG. 3, a transceiver transmission unit for transmitting an ultra wide band according to an embodiment of the present invention includes a CRC encoder 301, a scrambler 303, a convolutional encoder 305, a channel interleaver 307, Unit 309, an RRC filter 311, an interpolation filter unit 313, and a transmission control unit 330.

The CRC encoder 301 is a part for receiving a protocol data unit (PDU) according to each length from an upper layer (MAC) and performing CRC encoding of the PDU. This CRC encoding is used for error detection in the radio receiver.

In the present invention, data of different lengths are received from an upper layer (MAC) depending on the type of data.

The scrambler 303 scrambles CRC-encoded protocol data units.

At this time, the scrambler 303 initializes the scrambler 303 register with the user ID in the case of the actual data message except for the call control message.

Convolutional encoder 305 is a part for convolutional encoding CRC-coded and scrambled protocol data units.

For example, the convolutional encoder 305 may use a rate-1/2 tail-biting convolutional code with Constraint Length 7. In the convolutional encoder 305, the initial value of the shift register may be set to the information bit value of the last 6 bits so that the values of the first and last shift registers of the convolutional encoder 305 may be the same have.

The channel interleaver 307 performs channel interleaving on the signal received from the convolutional encoder 305. At this time, the channel interleaver 307 may perform bit collection for collecting two sequences.

The channel interleaver 307 transmits the channel-interleaved signal to the symbol mapping unit 309.

The symbol mapping unit 309 maps a signal (bit string) received from the channel interleaver 307 to a specific symbol (e.g., a QAM symbol). For example, the symbol mapping unit 309 maps a bit string received from the channel interleaver 307 to a QAM symbol from a most significant byte (MSB) in a gray scheme. At this time, the modulation rate of the symbol transmission is 5ksymbol / sec.

A Root-Raised Cosine (RRC) filter 311 functions to limit a band of a signal to an ultra-narrow band (for example, 6.25 kHz). Thus, the RRC filter 311 affects the RF signal quality.

The RRC filter 311 may have a roll-off factor of 0.1 and an example of the RRC filter 311 may be Equation 2 below.

The interpolation filter unit 313 performs interpolation. The interpolation filter unit 313 includes a first interpolation filter 3131 and a second interpolation filter 3132.

The first interpolation filter 3131 has an interpolation rate that is 8 times the symbol transmission rate and the second interpolation filter 3132 has 4 times the symbol transmission rate (1/2 of the first interpolation filter 3131) Times the interpolation rate of the interpolation rate.

As described above, the interpolation filter unit 313 performs interpolation in two stages to perform interpolation more efficiently.

In order to form a frame in the transceiver unit, the transmission control unit 330 configures the above-described data symbol in the protocol data unit, adds the pilot symbol according to the frame after the transmission of the preamble signal, and controls to transmit the data symbol together with the data symbol to the transceiver Section.

The transmission control unit 330 generates a control frame if the data is control data, and controls to generate an actual data frame if the data is actual data.

FIG. 4 illustrates a transceiver receiver for ultra-narrow band transmission according to an embodiment of the present invention. Referring to FIG.

Referring to FIG. 4, the transceiver receiver for the ultra high bandwidth transmission according to an embodiment of the present invention includes a reception filter unit 401, a frame / symbol synchronizer 403, a frequency synchronizer 405, a channel equalizer 407 A soft decision demodulator 409, a CINR / RSSI measurer 411, a frequency offset estimator 413, a channel deinterleaver 415, a Viterbi decoder 417, a descrambler 419, a CRC decoder 421, And a reception control unit 430. [

The reception filter unit 401 performs downsampling to have a symbol transmission rate of any rate (for example, 5ksps x Fs) lower than a specific rate for symbols sampled at a specific rate (for example, a rate of 10.24Msps) It is the part that performs.

The reception filter unit 401 includes a DCO (Digital Controlled Oscillator) unit. The DCO unit downconverts a signal of a specific channel frequency (for example, 6.25 kHz channel frequency) of a corresponding frequency band to a baseband Function.

The reception filter unit 401 includes an RRC reception filter including an NCO, a 2-decimator, and a matched filter, and the RRC reception filter can perform a down-sampling function of 64 times.

The frame / symbol synchronizing unit 403 performs frame synchronization and symbol synchronization. The frame / symbol synchronizer 403 performs frame synchronization and symbol synchronization to provide Optimum Symbol Timing for the difference between the propagation delay time of the received signal and the maximum delay spread according to the radio channel environment .

At this time, the frame synchronization can perform an optimal time synchronization process using a preamble signal having a length of 54.

Further, the frame / symbol synchronizer 403 can estimate an optimal sample time having a maximum correlation value in a specific sample unit (for example, Ts / 8 sample unit) together with frame synchronization.

The frame / symbol synchronization unit 403 may include a time synchronization unit of a sequence matched filter type so as to enable fast time synchronization acquisition.

5 illustrates a time synchronization unit according to an embodiment of the present invention.

라고 정의할 때 아래 수학식 3으로 최적의 수신신호 시작 위치를 추정할 수 있다.
Referring to FIG. 5, a correlation output of a sequence matched filter at a sample offset of nTs + kTs / 8

The optimal reception signal start position can be estimated by Equation (3) below.

here,

The frequency synchronization unit 405 is a unit for correcting a frequency error occurring on the radio channel.

The frequency synchronization unit 405 performs a frequency offset compensation on the preamble period of the received signal.

For example, the frequency synchronization unit 405 may apply a maximum likelihood (ML) frequency offset estimation method to perform precise frequency synchronization at intervals of 30 Hz. In addition, the maximum frequency offset compensation range can be set to [-120 Hz, 120 Hz].

The channel equalizer 407 removes inter-symbol interference (ISI) due to a radio channel.

6 illustrates a channel equalizer in accordance with an embodiment of the present invention.

6, the channel equalizer 407 includes an initial channel estimator 610, an adaptive channel estimator 620, an EQ coefficient calculator 630, ), A decision feedback equalizer (DFE) unit 640, and a symbol decision unit 650 (Symbol Decision).

The channel equalizer 407 calculates an initial equalization coefficient using the last 8 symbols of the preamble sequence in the initial channel estimator 610 and performs equalization on the data symbol by channel tracking based on a decision-directed (DD) Performs updating of the coefficients.

The channel equalizer 407 suppresses accurate channel tracking and error propagation due to DD through a pilot symbol in the received signal.

In addition, the channel equalizer 407 performs adaptive channel estimation in the adaptive channel estimator 620 for compensating the variation of the radio channel due to the Doppler effect due to the movement of the transceiver.

The channel equalizer 407 performs decision feedback equalization in the DFE unit 640 to efficiently remove inter-symbol interference.

The soft decision demodulator 409 is a part that performs symbol demapping.

For example, the soft decision demodulator 409 calculates a Log-likelihood Ratio (LLR) value by sign bit for a received demodulation symbol (e.g., a QAM demodulation symbol).

번째 송신 심볼

의

번째 구성 비트

에 대한 조건부 확률(Conditional Probability)의 LLR을 아래 수학식 4와 같이 계산한다.
The soft decision demodulator 409 demodulates the received demodulated symbol based on ML (Maximum Likelihood)

Th transmission symbol

of

Th configuration bit

The LLR of the Conditional Probability is calculated by Equation (4) below.

는 한 변조 심볼을 구성하는

번째 구성 비트가

인 변조 심볼 집합을 의미하고 맥스-로그 근사치(Max-log approximation)을 사용하여 아래 수학식 5와 같이 단순화 시킬 수 있다.
here,

Lt; RTI ID = 0.0 >

The second configuration bit is

And can be simplified as shown in Equation (5) below using a Max-log approximation.

The CINR / RSSI measurer 411 measures Carrier to Interference and Noise Ratio (CINR) and RSSI (Received Signal Strength). The CINR / RSSI measurer 411 measures the CINR and the RSSI and reports the results of radio link quality measurement between terminals such as a radio to the upper layer.

The CINR / RSSI measurer 411 calculates the power ratio of the error signal and the signal obtained through the difference between the output R (n) of the channel equalizer 407 and the soft decision result S (n) Can be calculated using Equation (6).

Where r (n) is received sample n

s (n) is synchronization sample corresponding to received symbol n

The CINR / RSSI measurer 411 calculates the RSSI as a sum of power for determining the signal power level of the received signal. This can be expressed by Equation (7) below.

The CINR / RSSI measurer 411 includes a DB-scale calculator. The DB-scale calculator calculates the dB value for the linear signal from the position of the MSB of the error power signal of the CINR calculator or the signal power signal of the RSSI calculator to "1" and from the position to the lower LSB of 3 bits.

The frequency offset estimator 413 estimates the frequency offset estimation for the received signal. The frequency offset estimator 413 estimates a frequency offset by measuring a phase difference between two adjacent pilot symbols.

를 갖고 수신신호에 대해 인접한 파일럿 심볼이 L개 심볼 간격을 갖는 경우에 파일럿 심볼에 대한 수신신호

은

으로써 아래 수학식 8과 같이 표현할 수 있다.Frequency offset

And the adjacent pilot symbols for the received signal have L symbol intervals, the received signal for the pilot symbol

silver

And can be expressed as Equation (8) below.

는 심볼 주파수 이다.here,

Is the symbol frequency.

Equation (9) is the final expression of the frequency offset estimator 413 obtained using Equation (8).

The channel deinterleaver 415 performs a reverse process of channel interleaving on the bit LLR sequence transmitted from the soft decision demodulator 409.

7 illustrates a Viterbi decoder according to an embodiment of the present invention.

7, the Viterbi decoder 417 includes a branch metric calculator 710, a path metric memory 720, an add-compare selector (ACS) 730, a survivor path memory 740, and an output generator 750.

The branch metric calculator 710 calculates the branch metrics of the individual stages for each received codeword bit in the received LLR. Here, the branch metric represents the hamming distance between the received symbol and all possible codewords

The path metric memory 720 is a block for storing the path metric (PM) of each state in the current stage. The path metric represents the cumulative value of the branch metric values of all stages in the past in the current stage on the trellis diagram.

The add-select selector 730 receives the two branch metric values and the path metric values, respectively, and compares the added values to select a smaller value among the two results.

The survivor path memory 740 stores the selected survivor path in the register in the ACS block in each state. Here, the register is allocated for each state, and the total length of the register is the same as the frame length.

The output generator 750 generates the output to be output.

The descrambler 419 initializes the descrambler 419 register with the user ID in the case of a data message excluding the call control message. Here, the generating polynomial for generating the descrambling code is the same as the generating polynomial for the scrambler 303. [

The CRC decoder 421 decides whether or not there is an error bit in the received bit sequence detected through the descrambler 419. Here, the generator polynomial for the CRC decoder 421 is the same as the CRC encoder.

The CRC decoder 421 performs LFSR on the binary output sequence of the descrambler 419 to declare error detection when the final register value is not all 0 (when the value divided by the CRC generator polynomial is not 0) 0, the received bit sequence with no error bit is configured as a PDU and reported to an upper layer.

The reception control unit 430 controls the radio receiving unit to decode the received signal.

The reception control unit 430 detects the reception signal, and divides the control frame including the control data and the actual data frame including the actual data, and controls the radio receiver to perform decoding corresponding to each of the control frames.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be appreciated that one embodiment is possible. Accordingly, the true scope of the present invention should be determined by the technical idea of the claims.

301: CRC encoder
303: Scrambler
305: convolutional encoder
307: channel interleaver
309: symbol mapping unit
311: RRC filter
313: Interpolation filter unit
3131: First interpolation filter
3132: 2nd interpolation filter
330: Transmission control section
401:
403: frame / symbol synchronization
405: frequency synchronizer
407: Channel equalizer
409: Soft decision demodulator
411: CINR / RSSI Meter
413: Frequency offset estimator
415: channel deinterleaver
417: Viterbi decoder
419: descrambler
421: CRC decoder
430:
610: Initial channel estimation unit
620: Adaptive channel estimation unit
630: EQ coefficient calculation unit
640: DFE section
650 symbol decision unit
710: Branch metric calculator
720: Path metric memory
730: Ad Select Select
740: Survivor Pass Memory
750: Output Generator

Claims (5)

A CRC encoder for performing CRC encoding of the protocol data unit,
A scrambler for scrambling the CRC-encoded protocol data unit,
A CRC encoding, a convolutional encoder for convolutional encoding the scrambled protocol data unit,
A channel interleaver for channel interleaving the signal received from the convolutional encoder,
A symbol mapping unit for mapping the signal received from the channel interleaver to a specific symbol,
An RRC filter for limiting the band of the signal to an ultra-
An interpolation filter unit for performing interpolation,
And a transmission control unit for generating a control frame if the data is control data and controlling the generation of an actual data frame if the data is actual data,
Wherein the interpolation filter unit includes a first interpolation filter and a second interpolation filter,
Wherein the interpolation rate of the first interpolation filter is twice that of the second interpolation filter,
The control frame is used for transmitting a call control message, an Ad-hoc radio link setup message, etc., and the control frame includes a preamble field of 64 symbols and all pilots of 320 symbols. Area and all data areas,
Wherein the actual data frame comprises the preamble region of 32 symbols and all the pilot regions and all the data regions of 352 symbols. delete delete delete delete

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