KR20110017659A - Ultra-wideband transreceiver for wireless body area network - Google Patents

Abstract

PURPOSE: An ultra-wideband transceiver for a WBAN(Wireless Body Area Network) is provided to more easily satisfy an FCC(Federal Communication Commission) emission mask by improving a UWB(Ultra-WideBand) signal at a frequency domain through the provision of a new transceiver structure for a WBAN network. CONSTITUTION: A transmitter(400) transfers a data channel signal used in a data channel of a WBAN and a control channel signal used in a control signal of a WBAN as a single modulation signal. A receiver separates the data channel signal and the control channel signal from the signal modulation signal. The receiver separates the data channel signal from the control channel signal through a PAM modulation by a bit unit, including plural pulses, if the control channel signal uses a narrow band.

Description

Wireless transceiver for WAN system {ULTRA-WIDEBAND TRANSRECEIVER FOR WIRELESS BODY AREA NETWORK}

Embodiments of the present invention relate to a UWB transceiver for data communication of a WBAN system.

Ultra-wideband (UWB) is a wireless technology that can be used at very low energy levels for short-range high-speed communications. It uses large bandwidth (> 500 MHz) to share spectrum with other systems. In UWB communication, transmission is performed so that interference with other conventional narrowband systems using the same frequency band is not large.

The Wireless Body Area Network (WBAN) system, on the other hand, consists of mobile, compact communication sensors that can be attached to or implanted in the human body and continuously monitors vital human variables and movements such as diabetes, asthma and heart attacks. These systems communicate using wireless technology and transmit data from the human body to the home base station. The transmitted data can be delivered in real time to hospitals and clinics.

UWB is proposed to be used in WBAN and is managed by IEEE task group 802.15.6. UWB is suitable for use in WBAN system for five reasons.

First, the main application of WBAN is healthcare, which is applied in spectrum-sensitive environments where low power radio waves must be emitted to the human body. The sensor must be compact (the sensor is expected to be implanted in the human body) and, therefore, can only support small, small capacity batteries. UWB has low radiated power and high power efficiency, making it an ideal technology for WBAN.

Second, since video is transmitted in real time in WBAN, the data rate must be guaranteed to some extent. Due to the short duration of the UWB pulses, it is easy to realize very high data rates, and the data rates can be easily exchanged for a range by simply integrating or combining the pulse energy of each data bit using coding techniques. .

Third, because of the wide bandwidth, UWB has a high spectral resolution, which is useful for real-time searching. In general, since information is collected based on the position of the sensor, navigation is an important problem in the WBAN system.

Fourth, the sensor used in the WBAN should be as small as possible, light in weight, easy to use, and reconfigurable. UWB meets these requirements.

Fifth, since most sensors are used within a limited area, multiple accesses are an important issue in WBAN networks, which can be easily realized by channelization codes such as time hopping (TH) codes or direct sequence spread spectrum (DS) codes in UWB. Can be.

WBAN technology based on UWB communication is still in its infancy, but research on it is extensive.

One embodiment of the present invention provides a UWB transceiver that can implement the characteristics and performance optimized for the WBAN system.

The UWB transceiver according to an embodiment of the present invention is an ultra-wideband (UWB) transceiver for data communication of a wireless body area network (WBAN) system, and a data channel signal and a WBAN used in a data channel of a WBAN network A transmitter for transmitting a control channel signal used in a control channel of the network as a single modulated signal; And a receiver configured to receive the data channel signal and the control channel signal separately from the single modulated signal.

In one embodiment of the present invention, the data channel uses a pulse position modulation (PPM) modulated signal according to a time hopping code (TH code).

In one embodiment of the present invention, the control channel uses a pulse amplitude modulation (PAM) modulated signal according to a miller code.

In one embodiment of the present invention, when the control channel signal does not use a narrow band, the receiver includes a hard decision and a plurality of pulses, which are made in symbol units including one pulse. The data channel signal and the control channel signal may be separated by performing a soft decision in units of bits.

In an embodiment of the present invention, when the control channel signal uses a narrow band, the receiver may separate the data channel signal and the control channel signal by PAM demodulation in units of bits including a plurality of pulses. have.

According to an embodiment of the present invention, it is possible to provide a new transceiver structure for a WBAN network, which can transmit data channel information together with control channel information through one modulation signal. Using this approach, the UWB signal is improved in the frequency domain so that the signal can more easily meet the Federal Communication Commission (FCC) emission mask. The reception performance of the control channel can be affected by the transmission rate, and the adjustment between the transmission rate and the reception performance can be interpreted in a new way. Due to the improved reception performance, the information of the control channel can be transmitted farther, which is advantageous for the construction and maintenance of the network. Best of all, this approach is very simple to implement and is compatible with existing pulse-based UWB systems, making it suitable for WBAN sensor networks.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited or limited by the embodiments. Like reference numerals in the drawings denote like elements.

The UWB transmission / reception apparatus according to an embodiment of the present invention performs a data transmission / reception function applicable to a WBAN system. The UWB transceiver may combine the data channel signal and the control channel signal into a single modulated signal in the physical layer. Pulse position modulation (PPM) and pulse amplitude modulation (PAM) may be used for modulation of the signal.

Signal composition

First, the format of the transmission signal will be described. Here, the format of the signal is divided into two parts. First, the PPM-TH UWB signal is used in the data channel of the WBAN to transmit information at high speed within limited interference. Second, the Miller coded control bits are modulated by PAM on the narrow bandwidth PPM-TH UWB signal and used as a control channel of the WBAN system.

1. Data channel signal

In the data channel, a PPM-TH UWB transmission signal is used, which is a monocycle, a series of short pulses. Monocycles typically have a constant duration It is a Gaussian pulse with T _p and zero outside the time interval [0, T _p ]. The duration is on the order of nanoseconds and yields a bandwidth on the order of GHz . 1 illustrates an example of a single bit waveform, where T _b = 5 T _s , T _s = 3 T _c , T _c = 2 T _p = 2 ε , ie N _s = 5, N _c = 3, T _p = ε ).

Waveform is duration It consists of a monocycle during T _b . Waveforms have a duration T _s is divided into N _s symbols ( T _s = T _b / N _s >> T _p ), and there is one monocycle in each symbol. Each symbol is divided into N _c chips, and the duration of each chip is T _c ( T _c = T _s / N _c > T _p ). The monocycle is located on a randomly selected chip according to the TH code. Considering the PPM modulation, the position of the monocycle in the chip is determined by the input bits. When ε < T _c , ε represents a position shift factor. In one embodiment of the present invention, since binary PPM is considered, simply set ε = T _p , and do not consider overlap by PPM between monocycles ( T _{c ≧} 2 ε ).

C _m ^(u) is the user Represents the TH code of the m th symbol of u . The TH code is used to specify the user, so it is the same in each bit for a given user. b _j ^(u) is the user indicates the j th bit of u and the user The waveform for transmitting the j th bit of u can be expressed briefly as follows.

Where w (t) represents a monocycle. user The transmission order of u may be defined as in Equation 1.

2. Control channel signal

According to an embodiment of the present invention, the Miller coded control signal is modulated in a PAM scheme and added to the data channel signal, thereby reducing power consumption.

Specifically, a Miller coded signal is generated for each bit of the control channel and modulated again using the PAM method. The modulated signal is multiplied by the corresponding monocycle of the data channel. In general, since the transmission rate of the control channel is much lower than that of the data channel, it is assumed that the bit rate of the data channel is 1 / T _b , and 1 / ( T _b × N _a ) represents the bit rate of the control channel. The bit duration of the control channel is T _b × N _a . 2 illustrates an example of a combined signal (1 control bit and 4 data bits) of a data channel and a control channel. Where T _a = 4 T _b .

The waveform is formed by monocycles modulated with PPM and PAM. The PPM carries the information of the data channel, and the PAM carries the information of the Miller coded control channel. When T _a = T _b × N _a , the bit duration of the control channel is Is T _a . The bits of the data channel and the control channel are independent, and therefore the modulation of the PPM and PAM is independent.

According to one embodiment of the present invention, the value of N _a should be large enough to obtain some advantages, but if the value is large, the bit rate of the control channel is reduced, so adjustment is necessary to determine the value. At least T _a and T _b are not the same value and differ from Direct Sequence-Impulse Radio (DS-IR). Miller encoding has the ability to convey timing information and excellent anti-interference capability, so one embodiment of the present invention employs Miller code. Another important point of interest in WBAN systems is that one bit can be transmitted in a narrow bandwidth compared to other baseband coding methods. That is, spectral efficiency is higher than other methods.

There may be polarity reversal in the middle of the Miller coded control bits, so that the polarity is stable for the control channel signal only for the duration of a half bit. a _i ^(u) represents the i th half bit of the control signal for user u , which has a duration equal to N _a / 2 data bits. N _a is defined as an even number to simplify the situation under consideration. Finally, considering Equation 1, the transmission order of user u may be defined as in Equation 2.

Where b _{i , j} ^(u) is the j ^t th data bit in the duration of the i th half bit of the control channel of the user u . Since one input bit is coded into two output bits by the Miller coding scheme, the duration of the coded control bits is T _a / 2, that is, the duration of N _a / 2 data bits.

Spectral analysis

In one embodiment of the present invention, the power spectral density (PSD) for the proposed scheme is analyzed and a receiver structure based on the proposed scheme is implemented.

1. Transmutative Description

One embodiment of the present invention considers signals of different channels independently to analyze the PSD. Equation 2 is modified as in Equation 3.

는 제어 채널의 신호를 나타내고,

는 데이터 채널의 신호를 나타낸다. 수학식 2의 신호는 펄스(모노싸이클)로 구성된 복합 신호이고, 수학식 3에서

만 펄스(모노싸이클)를 나타내고,

는 PAM방식으로 변조된 밀러 코드화 신호이다. 이때, 수학식 3은 펄스에 대한 표현을 포함하지 않는다. 따라서, 제어 채널의 신호가 PAM방식으로 변조된 후 데이터 채널의 신호와 곱해진 신호가 전체 신호로 보여질 수 있다. 변조 후 제어 채널 및 데이터 채널 모두의 신호가 하나의 신호로 합하여진다.here,

Represents the signal of the control channel,

Denotes the signal of the data channel. The signal of Equation 2 is a complex signal consisting of a pulse (monocycle),

Represents a full pulse (monocycle),

Is a Miller coded signal modulated by the PAM method. In this case, Equation 3 does not include an expression for the pulse. Therefore, after the signal of the control channel is modulated by the PAM method, the signal multiplied by the signal of the data channel can be seen as a whole signal. After modulation, the signals of both the control channel and the data channel are summed into one signal.

2. Mathematical Expression

When one user is determined, the Fourier transform of Equation 3 is equal to Equation 4.

Where * is the convolution operator, W _C (f) is the PSD of the Miller coded control signal, and W _D (f) is the PSD of the data channel signal PPM-TH UWB.

W _C (f) can be obtained from equation ( 5 ) , and W _D (f) can be obtained from equation (6).

)(only,

)

이고, W ₀ (f) 는 모노싸이클의 PSD이다.)(only,

And W ₀ (f) is the PSD of the monocycle.)

Dividing Equation 6 into continuous and discrete components, the PSD of the proposed scheme is obtained by convolution of W _C (f) and the two component angles.

2-1. Convolution of W _C (f) with Continuous Components

In Equation 7, the elements that determine the bandwidth of W _v (f) and W _C (f) are T _p and T _a, respectively. W _C (f) is a narrowband signal compared to W _v (f) because T _p is much larger than T _a . Therefore, influenced by the PSD are W _v (f) amplitude man W _C (f) of the PSD and holding substantially the same form, and W ₁ (f) of the expression in equation (7). The proposed scheme is still a pulse based UWB PSD, the main power is still concentrated at [0, 5 / T _p ], and the bandwidth of the proposed scheme is 5 / T _p .

2-2. Convolution of W _C (f) with Discrete Components

In Equation 8, the PSD of the Miller coded control channel signal is transferred to f = n / T _b after the amplitude is slightly changed, and becomes symmetric at f = n / T _b . When T _a increases, W ₂ (f) also increases according to Equation 5, which means that the power peak increases.

In addition, considering the influence of the change in amplitude,

가 된다.

Becomes

W ₀ (f) is a PSD of a Gaussian type monocycle, which is almost constant in bandwidth [0, 5 / T _p ]. The peak value is obtained in Equation 9 only when n = kT _b / T _p , and the PSD value is very low for other n values. In this case, k may be a positive integer element.

Substituting n = kT _b / T _p into Equation 8, there is a significant PSD peak only when f = n / T _P. This means that the Miller coded control channel information is delivered with significant power to the spectral position f = k / T _p , and the power at the rest of the spectral position is very small and can be ignored. It can be seen that the main power of the Gaussian type UWB signal is concentrated at [0, 5 / T _p ], and the transmitted control channel signal is mainly f = k / T when k = 1,2,3,4,5. It can be said that it exists in _p .

Parameters for simulating the proposed scheme in one embodiment of the present invention are set as shown in Table 1.

3 is a simulation of the PSD, (a) the theoretical PSD of the Miller code, (b) the PSD of the Miller coded control channel signal, (c) the PSD of the data channel signal (PPM-TH UWB), (d ) Shows a PSD of the proposed scheme, (e) shows a PSD near 2 GHz of the data channel signal PPM-TH UWB, and (f) shows a PSD near 2 GHz of the proposed scheme.

In Fig. 3 (a), W _C (f) does not contain a discrete component, and the spectral efficiency is approximately 2 bit / s / Hz. In Equation 5, increasing T _a increases the peak value of the PSD, and timing information is included in the signal for Miller coding, which is advantageous for preventing noise. For this reason, an embodiment of the present invention adopts a baseband coding method.

3 (c) to 3 (f) illustrate the spectral characteristics of the PPM-TH UWB and the scheme proposed in one embodiment of the present invention. In conclusion, the presence of discrete PSDs for PPM-TH UWB, and the large proportion of discrete PSDs that do not carry any valuable information, wastes most of the power and decisively violates regulations on radiated power. . On the other hand, in the proposed scheme according to an embodiment of the present invention, since most discrete PSDs are suppressed and some discrete PSDs are replaced with valuable control channel information, power efficiency is increased and regulation of radiated power is restricted. You will be satisfied.

In FIG. 3 (d), the peaks of power occur at 2 GHz, 4 GHz, 6 GHz and 8 GHz, which leads to conclusions on the control channel signal ( f = k / T _p , k = 1,2,3,4,5). Can prove. At 10 GHz, the PSD is too small to be considered.

3 (e) and (f) show the PSD in the vicinity of 2GHz of the PPM-TH UWB and the scheme proposed in one embodiment of the present invention, respectively. The discrete PSD of FIG. 3 (e) is replaced with the continuous PSD of FIG. 3 (f). In addition, comparing FIGS. 3 (b) and 3 (f), the information of the control channel is accurately transmitted in the vicinity of 2 GHz, which is a discrete pulse not used in the PPM-TH UWB, which is also consistent with the analysis of the control channel signal.

The characteristics of the proposed scheme can be summarized as follows.

First, two channels transmit information by one signal.

Second, the PSD in the UWB system is improved, reducing power dissipation and making it easier to meet FCC masks.

Third, since the information of the control channel is transmitted through some narrow band in the frequency domain, control information can be transmitted and received through this special narrow band.

In FIG. 3 (d), since the PSD of the spectral position used to transmit the information of the control channel is much larger than the PSD of the other spectral position, this power peak may violate the regulation on power emission (FCC mask). If the power peak violates the power emission regulation, we know that the bandwidth of the power peak is narrowband, so we can assume that a legitimate bandwidth is applied to the system at the location of the power peak.

UWB  Transceiver

In one embodiment of the present invention, a UWB transceiver is implemented in consideration of two cases (whether the power peak violates the FCC mask).

One embodiment of the present invention considers a receiver that is most suitable for Additive White Gaussian Noise (AWGN). In the following, it is assumed that transceivers for any user u are specified and synchronization is complete.

1. Transmitter

4 illustrates a structure of a transmitter 400 of a UWB transceiver according to an embodiment of the present invention, and is proposed in consideration of a transmitter structure of a PPM-TH UWB.

가 주어지고, 이는

의 비율로 생성된다. 펄스의 발생을 담당하는 반복 인코더(401)에 의하여 각 비트가 N _s 회 반복된다. 이 후, 비트 지속기간이 T _s 로 변경된다. 전송 인코더(402) 내에서 각 펄스의 위치가 쉬프트된다.Binary Sequence for Data Channels

Is given,

Is generated at the rate of. Each bit is repeated N _s times by a repeat encoder 401 which is responsible for generating the pulse. After this, the bit duration is changed to T _s . The position of each pulse within the transmit encoder 402 is shifted.

의 비율로 발생하고, 이 비율은 계속 유지된다. 밀러 인코더(403)에서 두 개 채널의 비트 전송률은 일치해야 한다. 즉, T _a =N _a ×T _b =N _a ×N _s ×T _s 이다. 여기서, N _s 는 데이터 채널에 의하여 결정되고, 데이터 채널의 수신 성능과 관계가 있다. N _a 는 제어 채널과 데이터 채널의 전송 속도의 차에 의하여 결정되고,

로 표현된다. <스펙트럼 분석> 항목에서 상기한 바와 같이 PSD는 N _a 와 관련이 있기 때문에(N _a 가 증가하면 T _a 도 증가하고, 따라서 PSD의 피크치도 증가한다) PSD도 고려되어야 한다. 또한, 제어 채널의 수신성능도 고려해야 한다.On the other hand, binary sequences for control channels

Occurs at the rate of, and this rate is maintained. In Miller encoder 403, the bit rates of the two channels must match. That is, T _a = N _a × T _b = N _a × N _s × T _s . Here, N _s is determined by the data channel and is related to the reception performance of the data channel. N _a is determined by the difference between the transmission rates of the control channel and the data channel,

It is expressed as (And N _a is increased with increase in the peak value of increase in T _a, and hence PSD) PSD is because they are associated with _a N as described above in <spectrum analysis> items should be considered PSD. In addition, the reception performance of the control channel should be considered.

A non-real multiplier 406 realizes a multiplier between two channels. The signal of the control channel is different from the signal of the data channel consisting of pulses. The signal of the control channel is a continuous direct current signal, in which polarity inversion occurs at the boundary or middle of the bit. Therefore, when the multiplication is performed, the signal of the control channel is simply used as the reference signal. If the reference signal is a negative region, the phase of the pulse of the data channel is inverted, otherwise there is no change. In M-ary PAM modulation, the amplitude of the reference signal may be used to regulate the transmission power.

The peak value of power after the pulse shaper 407 may exceed the FCC mask. In this case, since the narrow band used by the control signal can be used as a legal spectrum band, a narrow band filter is necessary to separate the control channel and the data channel.

2. Receiver

이고, 채널 페이딩이 포함되어 있으면

이다. 여기서,

는 페이딩 팩터이다. 펄스의 모양에 미치는 송수신기 안테나의 영향은 이미 송신기(400) 측의 펄스 성형기(407)에서 완벽하게 고려한 것으로 가정한다.It is assumed that the signal is transmitted through a zero mean, and N _0/2 variance AWGN channel without interference between multiple users. The incoming signal is

, If channel fading is included

to be. here,

Is the fading factor. It is assumed that the influence of the transceiver antenna on the shape of the pulse has already been fully considered in the pulse shaper 407 on the transmitter 400 side.

FIG. 5 illustrates a structure of a receiver 500 of a UWB transceiver according to an embodiment of the present invention, and illustrates an optimal receiver structure of a single pulse.

2-1. Without narrowband filter 501

If the peak value of the transmission power is within the emission regulation range, the narrow-band filter 501 is not required on the receiver 500 side, and the received signal is both a UWB signal for the data channel and the control channel, and the pulse shape for the control channel is obtained. Keep it.

It is assumed that the synchronization between the transceivers is completed, that is, the receiver 500 knows all T _a , T _b , T _s , T _c , T _p , and C _m . The two decision rules on the receiver 500 side are as follows.

a) hard decision

The correlation template for hard decision consists of a single pulse in each received symbol time. For data channels

이고

ego

For control channels

이다.

to be.

Where w ₀ (t) is the energy normalization pulse. In order to determine one bit in the data channel, N _s pulses representing one bit are independently determined, and the final result is simply obtained by the majority vote principle from the N _s decision results. Similarly, N _a / 2 × N _s pulses representing one bit are independently determined to determine one bit in the control channel. In the hard decision, the decision is made in units of symbols including only one pulse.

b) annual determination

The receiver template for the open decision in the data channel consists of N _s pulses within each receive bit time.

In the soft decision detection, the receiver 500 regards the signal consisting of N _s pulses as a multi-pulse signal. The received signal is cross correlated with the receiver template, which matches a series of pulses representing the entire symbol. The determination is made bit by bit.

(Where N _d = N _a / 2 × N _s )

6 shows templates for various types of receivers. In the data channel, after passing the full wave rectifier 502, the received signal is the same as in a conventional PPM-TH UWB system. In the control channel, the received template is modulated by the PAM and PPM modulators so that the receiver template is different from the existing PAM UWB. Thus, the receiver template simply repeats the pulse at two positions. This results in poor reception performance when the narrowband filter 501 is not present.

2-2. If there is a narrowband filter 501

If a narrowband filter 501 is included on the receiver 500 side corresponding to the transmitter 400 side, the pulse shape of the data channel is composed of UWB pulses, and the demodulation procedure thereof is the same as without a narrowband filter. Do. In the control channel, since the pulse shape on the receiver 500 side is damaged, the signal cannot be demodulated based on the pulse, but the information can be restored by the PAM correlation demodulation method.

According to the <spectrum analysis> item, the duration of one control bit is T _a, and after the Miller coding, the duration of the inverted polarity is T _a / 2. Thus, the correlation template of the receiver 500 is

이다.

to be.

Where E ₀ ( t ) is the energy normalization sphere, and its duration is half of one control bit.

If the narrowband filter 501 is included in the control channel, the pulse cannot be distinguished from the control channel (if N _a is large enough, only the envelope of the pulse sequence is maintained), and thus the hard decision cannot be performed. In the soft decision, if the control channel includes a narrowband filter 501, T _d = T _a / 2.

Receiving performance

1. Data Channel

In the data channel, since the decision is the same as the existing PPM-TH UWB, the reception performance of the open decision in the AWGN channel is

이다.

to be.

이고, E _D 는 데이터 채널의 비트 당 수신된 에너지, E _X 는 펄스 당 수신된 에너지를 나타낸다. 비트 당 펄스의 수를 증가시킴으로 수신에너지는 N _s 만큼 증가하고, 그 결과 비트 에러율이 감소한다. 이는 평균 송신 파워를 증가시키지 않고 이룰 수 있으며, 이에 대한 손실로 비트 당 분주율(dividing rate)이 증가한다.here,

Where E _D represents the energy received per bit of the data channel, and E _X represents the energy received per pulse. By increasing the number of pulses per bit, the received energy increases by N _s , resulting in a decrease in the bit error rate. This can be achieved without increasing the average transmit power, which results in an increase in the dividing rate per bit.

In the hard decision, the number of pulses falling at a position above the threshold is given, and if the number of falling pulses is compared with the number of pulses falling at a position below the threshold, the predicted bit matches the larger of the two pulses. . If more than half of the pulses are incorrectly recognized, an error occurs, and the probability of a bit error is given by Equation 10.

는 하나의 프레임에서의 판정 오류율이다.only,

Is the decision error rate in one frame.

2. Control channel

2-1. Without narrowband filter 501

First, the receiver performance for a single pulse is calculated.

The control channel may have four received signals.

Where E _X is the energy received per pulse. Also, a is the transmitted bit of the data channel and b is the transmitted bit of the control channel.

) 상관관계의 결과를 얻기 위하여 템플리트를 사용한다고 가정하면, 적분기(503)를 통과한 후의 신호는

와 같다.The signals are orthogonal to each other (

Assume that we use a template to obtain the correlation result, the signal after passing through the integrator 503

Same as

이다. 독립적이고 확률이 동일한 전송 비트에 대하여 평균오류확률은 Where n ₀ is a Gaussian random variable with mean zero and variance N ₀ ,

to be. The average error probability for independent and equally transmitted bits is

와 같이 표현할 수 있다.

It can be expressed as

The overall error probability is expressed as in Equation 11.

The error rate of the control channel is the same as that of the data channel, which is inferior to the conventional PAM-TH UWB. This is because the longer the duration of the integrator 503, the more noise is generated in the receiver.

Similar to the case of a single pulse, the performance of the soft decision is easy to obtain.

Where E _C is the energy received per bit of the data channel and E _X is the energy received per pulse. Since the received bit is _a Miller coded bit with _a duration of T _a / 2, the duration of the received bit is T _a / 2. N _s x N _a / 2 pulses are included in one receive bit. Decoding effects in the Miller decoder 505 will be described later with reference to FIG. 7.

The performance of the hard decision can be obtained by substituting Equation 11 into Equation 10.

2-2. If there is a narrowband filter 501

In this case, the bits of the control channel are represented by rectangles rather than pulse shapes. The spherical duration is T _a / 2, and the bits of the control channel are modulated by PAM. Demodulation performance is expressed as follows.

이고, n’ ₀ 는 평균이 제로이고 분산이 N ₀ /2인 가우시안 확률변수이고,

이다.Using template m ₂ '(t) , the output of correlator 504 of the control channel in FIG. 5 is

And, n _'0 is the mean is zero and variance N _0/2 of Gaussian random variables,

to be.

If E _C and E _D are the same, the error rate of the control channel is equal to the error rate of the data channel. However, considering the reception performance in the case of E _C = N _a / 2 × E _D , it can be seen that the reception performance of the control channel is superior to the reception performance of the data channel. This is useful for controlling and maintaining WBAN networks. Similar to the data channel, the reception performance of the control channel may be expressed as Equation 13 in the hard decision.

3. Error Considerations for Miller Decoding

In calculating the error rate in the control channel, only the error rate before Miller decoding is considered. The influence of Miller decoding is as follows.

If there is an error signal before decoding at Miller decoder 505, a bit of error occurs.

In FIG. 7A, if two adjacent received bits have an error, two bit errors occur in the decoded bit sequence. In addition, as shown in FIG. 7B, there may be no bit error. Because of the randomness of the error, the probability of both cases is the same. Thus, the error to be decoded is one bit for two adjacent error bits.

Similarly, m = [1, 2,... ], There is only one bit error for n consecutive errors. The error probability is as shown in Equation 14.

Where Pr _m is the decoding error rate of m consecutive error input bits. Since m consecutive error bits are composed of m consecutive error bits and one correction bit positioned at the end of each error sequence, the following equation (15) can be obtained.

Equation 16 from Equation 14 and Equation 15

을 얻고,

Gained,

Substituting the error rate equation (13) in the control channel into Equation (16) yields the final bit error rate of the control channel.

One embodiment of the present invention can provide a new transceiver structure for a WBAN network, which can transmit data channel information along with control channel information through one modulation signal. Using this approach, the UWB signal is improved in the frequency domain so that the signal can more easily meet the FCC mask. The reception performance of the control channel can be affected by the transmission rate, and the adjustment between the transmission rate and the reception performance can be interpreted in a new way. Due to the improved reception performance, the information of the control channel can be transmitted farther, which is advantageous for the construction and maintenance of the network. Best of all, this approach is very simple to implement and is compatible with existing pulse-based UWB systems, making it suitable for WBAN sensor networks.

The proposed scheme in one embodiment of the present invention can be easily extended to the M-ary case. The M-ary method can further improve performance. This approach can be realized based on a PAM UWB system, and other multi-access coding methods can be used for such a system.

As described above, the present invention has been described by specific embodiments such as specific components and the like. For those skilled in the art to which the present invention pertains, various modifications and variations are possible.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and all of the equivalents or equivalents of the claims as well as the claims to be described later will belong to the scope of the present invention. .

1 is a diagram illustrating an example of a data channel.

2 is a diagram illustrating an example of a combined signal of a data channel and a control channel.

3 is a view for explaining the simulation of the PSD.

4 and 5 are diagrams illustrating a structure of a transmitter and a receiver of a UWB transceiver according to an embodiment of the present invention.

6 shows an example of a template for a receiver.

FIG. 7 illustrates two bit errors generated in Miller decoding.

<Explanation of symbols for the main parts of the drawings>

400: transmitter

500: receiver

Claims (5)

In the ultra-wideband (UWB) transceiver for data communication of a wireless body area network (WBAN) system, A transmitter for transmitting a data channel signal used in a data channel of a WBAN network and a control channel signal used in a control channel of the WBAN network as a single modulation signal; And, A receiver which receives the data channel signal and the control channel signal separately from the single modulated signal UWB transceiver device comprising a. The method of claim 1, The data channel, UWB transmission and reception apparatus using a pulse position modulation (PPM) modulated signal in accordance with a time hopping code (TH code). The method of claim 1, The control channel, A UWB transmission / reception apparatus using a pulse amplitude modulation (PAM) modulated signal in accordance with a miller code. The method of claim 1, The receiver, When the control channel signal does not use a narrow band, a hard decision made in a symbol unit including one pulse and a soft decision made in a bit unit including a plurality of pulses And separating the data channel signal from the control channel signal. The method of claim 1, The receiver, If the control channel signal uses a narrow band (Narrow band), UWB transmitting and receiving device for separating the data channel signal and the control channel signal by PAM demodulation in units of bits including a plurality of pulses.

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