KR102108825B1 - Apparatus and method for communication in nanonetwork - Google Patents

Abstract

This embodiment is a terahertz band-based nano network communication device, a pulse generator for generating a pulse having a predetermined duty cycle, DS-OOK modulation using a spreading code for the generated pulse and user data A modulator for generating a modulated signal by performing, and a transmitter including a transmit antenna for transmitting the modulated signal through a terahertz band channel, and a receiver for demodulating the transmitted modulated signal using the same code as the spreading code. Including, the receiver provides a nano-network communication device that considers a signal received from a transmitter other than a specific transmitter for which predicted delay and spreading code information is known.

Description

Nano network communication device and method {APPARATUS AND METHOD FOR COMMUNICATION IN NANONETWORK}

Embodiments of the present invention relate to a nanonetwork communication device and method.

The contents described below merely provide background information related to the embodiments according to the present invention, and do not constitute the prior art.

The nanotechnology, first discussed by Professor Richard Feynman in 1959, is now being used to prototype nanoscale devices called nanomachines. A nanomachine is a device that can be manufactured in the size of hundreds of nanometers and perform simple tasks such as simple calculation and sensing. Since the nano-machine has limited sensing range, battery, and processing power, it can only perform complex tasks when it is connected in the form of a nanonetwork.

Since the nanonetwork is a random network composed of a very large number of nanodevices, a modulation technique and multiple access (MA) that supports simultaneous channel access of nanodevices to perform smooth communication ) Development of techniques is being requested. In addition, there are time spread OOK (TS-OOK) and rate division (RD) TS-OOK as nano-network communication techniques that meet such requests.

TS-OOK supports time spread multiple access by using symbols having a transmission interval unique to each user, which is much larger than a pulse width. That is, when using the TS-OOK technique, the receiver is able to distinguish signals transmitted from multiple users (ie, transmitters) through signal transmission intervals that are different for each user and are much larger than the pulse width.

In addition, RD TS-OOK supports rate division multiple access by transmitting user data at a different symbol rate for each user. That is, when using the RD TS-OOK technique, the receiver can distinguish signals transmitted from multiple users (ie, transmitters) through different symbol rates for each user.

1 is a conceptual diagram showing a nano-network communication device using the TS-OOK technique.

The nano-network communication apparatus 100 using the TS-OOK technique includes a transmitter 110 and a receiving antenna 122 including a pulse generator 112, a modulator 114, and a transmitting antenna 116, a detector 124, and a demodulator It includes a receiver 120 including (126).

The pulse generator 112 generates pulses and delivers them to the modulator 114. The modulator 114 generates a modulated signal by performing TS-OOK modulation based on the pulse and user data generated by the pulse generator 112. Here, since the symbol interval of the modulated signal is different for each user (ie, transmitter), multiple access (MA) is possible at the receiver.

The modulator 114 may further include a timing information generator 115. The timing information generator 115 generates timing information used for synchronization of the transmitter 110 and the receiver 120. For example, the timing information generator 115 generates preamble information for providing time information. Then, the modulated signal generated by the transmitter 110 is transmitted through the channel by the transmission antenna 116. The detector 124 of the receiver 120 detects the modulated signal received through the receive antenna 122, and the demodulator 126 demodulates the detected modulated signal to restore user data.

However, the nano-network communication apparatus 100 using the TS-OOK technique has a problem in that it is difficult to distinguish received signals or noise from each other when the pulses of signals transmitted from different transmitters overlap. have.

Therefore, in the nano-network, there is a need for a communication technique capable of supporting multiple accesses with low complexity, high energy efficiency, and minimal interference.

Embodiments of the present invention are to provide a nano-network communication apparatus and method for enabling multiple access communication with minimal interference while having low complexity and high energy efficiency.

According to an aspect of the present embodiment, a terahertz band (Terahertz band) -based nano-network communication apparatus, a pulse generator for generating a pulse having a predetermined duty cycle, the generated pulse and user data spreading code (spreading code) A transmitter including a modulator that generates a modulated signal by performing DS-OOK modulation using), and a transmit antenna that transmits the modulated signal through a terahertz band channel; And a receiver that demodulates the transmitted modulated signal using the same code as the spreading code, wherein the receiver is from a transmitter other than a specific transmitter for which predicted delay and spreading code information is known. Provided is a nano-network communication device that regards a received signal as an obstacle.

According to another aspect of this embodiment, a terahertz band-based nanonetwork communication method, comprising: generating a pulse having a predetermined duty cycle; Generating a modulated signal by performing DS-OOK modulation using a spreading code on the generated pulse and user data; And transmitting the generated modulation signal through a terahertz band channel, wherein the transmitted modulation signal is demodulated using the same code as the spreading code, and an expected delay and spreading code. ) A signal transmitted from a transmitter other than a specific transmitter for which information is known provides a nanonetwork communication method, which is regarded as a failure.

The terahertz band-based nano network communication apparatus and method according to the present embodiment has an effect of supporting multiple access communication with minimal interference.

1 is a conceptual diagram showing a nano-network communication device using the TS-OOK technique.
2 is a conceptual diagram showing a nano-network communication device according to an aspect of the present embodiment.
3 is an exemplary view showing a pulse waveform that can be used in this embodiment.
4 is a conceptual diagram illustrating a nano network communication device according to another aspect of the present embodiment.
5 is a conceptual diagram illustrating a communication device when a plurality of transmitters are present in the nanonetwork according to the present embodiment.
6 is a graph showing a simulation result by applying a pseudo-random binary code to the nano network communication apparatus according to the present embodiment.
7 is a graph showing a simulation result by applying a simulated annealing code to the nanonetwork communication device according to the present embodiment.
8 is a graph showing performance comparison results when a pseudo-random binary code and a simulated annealing code are applied to a nanonetwork communication device according to the present embodiment.
9 is a flowchart illustrating a nanonetwork communication method according to the present embodiment.

Hereinafter, some embodiments of the present invention will be described in detail through exemplary drawings. It should be noted that in adding reference numerals to components of each drawing, the same components have the same reference numerals as possible, even if they are displayed on different drawings. In addition, in describing embodiments of the present invention, when it is determined that detailed descriptions of related well-known structures or functions may obscure the subject matter of the present invention, detailed descriptions thereof will be omitted.

In addition, in describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are only for distinguishing the component from other components, and the nature, order, or order of the component is not limited by the term. Throughout the specification, when a part is 'included' or 'equipped' a component, this means that other components may be further included rather than excluded, unless specifically stated otherwise. . In addition, '… The terms "unit" and "unit" mean a unit that processes at least one function or operation, which may be implemented by hardware or software or a combination of hardware and software.

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

2 is a conceptual diagram showing a nano-network communication apparatus according to an aspect of the present embodiment, Figure 3 is an exemplary view showing a pulse waveform that can be used in this embodiment.

Referring to FIG. 2, the nanonetwork communication device 200 includes a transmitter 210 and a receiver 220.

The transmitter 210 may include a pulse generator 212, a modulator 214 and a transmit antenna 216.

The pulse generator 212 generates a pulse having a preset pulse duration and a preset duty cycle. Here, the frequency of the pulse may have a frequency between 0.1 THz and 10 THz. That is, the pulse width may be greater than or equal to 10 fs and less than 10000 fs.

The pulse generator 212 may be implemented using a conventional semiconductor device, for example, an oscillator, an amplifier, a frequency multiplier, and the like, and the detailed implementation method will be apparent to those skilled in the art, and thus detailed description Will be omitted.

Referring to FIG. 3, the pulse p (t) generated by the pulse generator 212 may be a Gaussian monocycle pulse having a pulse-width of several hundred femtoseconds. And, assuming that the pulse duration is T _p and the symbol duration is T _s , the duty cycle is T _p / T _s , and the pulse p (t) is math. It can be expressed as Equation 1.

Here, e is a natural constant, A is the amplitude of the pulse p (t), and f _c is the center frequency of the pulse p (t).

Returning to FIG. 2 again, the modulator 214 may generate a modulated signal using pulses generated by the pulse generator 212 and data input from outside.

According to an aspect of the present embodiment, the modulator 214 is based on the pulse and user data generated by the pulse generator 212, direct spread on-off modulation (direct sequence on-off keying: DS-OOK) A modulation signal can be generated by performing. Specifically, the modulator 214 may allocate data bit 1 when there is a pulse received from the pulse generator 212, and allocate data bit 0 when no pulse is received from the pulse generator 212. .

The modulator 214 can use a specific code to modulate the pulse received from the pulse generator 212. Here, the specific code may be a spreading code, for example, a random spreading code having a value of +1 or -1. In this case, the modulator 214 may generate a modulated signal by spreading the signal by multiplying each pulse by a user-specific spreading code having a size of ± 1. According to an aspect of the present embodiment, the spreading code may include a pseudo-random binary code (PRN) and a simulated annealing code (SA).

Considering antipodal modulation for a binary symbol, the signal waveform s ^(k) (t) transmitted by the k-th user may be expressed as Equation (2).

Here, p (t) is a pulse defined by Equation 1, b ^k _j is a modulated data symbol (1 or 0) for the k-th user, and a ^k _n is a spreading code for the k-th user. In addition, the symbol duration T _s may be expressed as a product of the number N of pulses per data bit and the period T _p of a single pulse (that is, T _s = N × T _p ).

The modulator 214 may further include a code information generator 215 to generate such a specific code. For reference, FIG. 2 shows that the code information generator 215 is included inside the modulator 214, but since this is exemplary, the code information generator 215 is separately formed outside the modulator 214. It may be.

The transmitting antenna 216 emits the signal generated by the modulator 214 in the form of an electromagnetic wave.

Meanwhile, the nanonetwork communication apparatus according to an embodiment of the present invention may be designed to use a terahertz band channel.

Since the terahertz band has a very high molecular absorption loss, unlike other frequency bands, a path loss model or a peak attenuation in a received signal frequently occurs. Can be.

Meanwhile, the channel model of the terahertz band can be expressed by using an impulse response as shown in Equation (3).

Here, H _eq (f) is an equivalent channel transfer function (Equivalent channel transfer function) can be expressed as Equation (4).

Here, H _spr (f, d) is a spreading loss transfer function, and H _abs (f, d) is a molecular absorption loss transfer function.

The receiver 220 may include a receive antenna 222, an RF front end 224, a bandpass filter 226, and a demodulator 228.

The reception antenna 222 receives a signal in the form of electromagnetic waves transmitted from the transmitter 210.

The receiving antenna 222 may include various types of antennas, such as a waveguide antenna and an on-chip antenna, and may be preferably implemented as a planar type antenna that is easy to integrate. However, it should be noted that this is an example, and the present embodiment is not limited thereto.

The RF frontend (RF frontend) 224 may include a low-noise amplifier (LNA), a mixer (mixer) and an oscillator (oscillator).

The low-noise amplifier (not shown) amplifies the weak signal received through the reception antenna 222 and transmits it to the mixer.

The mixer (not shown) down-converts the received signal amplified by the low-noise amplifier to the IF frequency domain and delivers it to the oscillator for accurate measurement of the high-frequency signal.

An oscillator (not shown) generates an oscillation signal using a frequency-converted signal by a mixer. According to one aspect of this embodiment, the oscillator may be a voltage controlled oscillator driven by a bias current having a quench waveform. In this case, the oscillator is applied with a Q-enhanced mode in which the frequency selectivity is increased by applying a high bias current and maximizing the Q value of the oscillation circuit based on a predetermined threshold current, or a low bias current is applied. It can operate in any one of super-regenerative modes that oscillate regardless of the magnitude of the input signal.

The bandpass filter (BPF, 226) removes unwanted waves from the signal transmitted from the RF front end 224.

The demodulator 228 restores the original data by demodulating the signal transmitted from the bandpass filter 226 using a specific code (eg, random spreading code) unique to each user (ie, transmitter). Here, information about a specific code may be included as a preamble of a received signal.

The demodulator 228 may further include a code information generator 229 to generate such a specific code. For reference, FIG. 4 shows that the code information generator 229 is included inside the demodulator 228, but since this is exemplary, the code information generator 229 is separately formed outside the demodulator 228. It may be.

4 is a conceptual diagram illustrating a nanonetwork communication device according to another aspect of the present embodiment.

The nano-network communication apparatus 400 of FIG. 4 has the same configuration except for the presence or absence of the nano-network communication apparatus 200 and the phase detector 425 described above with reference to FIG. 2, and thus, with reference to FIG. Descriptions of parts overlapping with the foregoing will be omitted or simplified.

Referring to FIG. 4, the nanonetwork communication device 400 includes a transmitter 410 and a receiver 420.

The transmitter 410 may include a pulse generator 412, a modulator 414 and a transmit antenna 416.

As described above with reference to Figure 3, the pulse generated by the pulse generator 412 is described above as a Gaussian monocycle pulse having a pulse-width of hundreds of femtoseconds. It can be expressed as Equation (1).

The modulator 414 may further include a code information generator 415 for generating a specific code used to generate a direct sequence on-off keying (DS-OOK) modulation signal. At this time, as described above, the code information generator 415 may be implemented as a separate module from the modulator 414.

The specific code may be a spreading code, for example, a random spreading code having a value of +1 or -1, and according to an aspect of the present embodiment, a pseudo-random binary code (PRN) And a simulated annealing code (SA).

The receiver 420 may include a receive antenna 422, an RF front end 424, a bandpass filter 426, and a demodulator 428.

The RF front end 424 may include a low-noise amplifier (LNA), a mixer, and an oscillator. In addition, unlike the receiver 220 described above with reference to FIG. 2, the RF front end 424 may further include a phase detector 425. Here, the phase detector 425 detects the phase of the received signal to perform binary modulation and demodulation using a spreading code.

The demodulator 428 may further include a code information generator 429 for generating a code identical to a specific code specific to each user used in the modulator 414 of the transmitting end. At this time, as described above, the code information generator 429 may be implemented as a separate module from the demodulator 428.

As such, the nanonetwork communication device 400 may be designed to use a terahertz band channel, and band characteristics and channel models are as described above with reference to FIG. 2.

5 is a conceptual diagram showing a nano-network communication device including a plurality of transmitters according to the present embodiment.

Referring to FIG. 5, the nanonetwork communication device 500 includes a first transmitter 510-1, a second transmitter 510-2, ..., an Nth transmitter 510-N, and a receiver 520. Includes. Here, N is a positive integer.

Each of the first transmitter 510-1, the second transmitter 510-2, ..., the Nth transmitter 510-N includes the same components as the transmitter 210 or 410 of FIG. 2 or 4 do. That is, each of the first transmitter 510-1, the second transmitter 510-2, ..., the Nth transmitter 510-N includes a pulse generator, a modulator, and a transmission antenna, and additionally, a code information generator It can contain. Here, the function of each component is as described above with reference to FIGS. 2 to 4.

Each of the first transmitter 510-1, the second transmitter 510-2, ..., and the Nth transmitter 510-N generates a pulse, and a specific code (eg, spreading code) different for each user is generated. It modulates each user data by using it, and radiates it in the form of electromagnetic waves through a transmission antenna.

The receiver 520 includes the same components as the receiver 220 or 420 of FIG. 2 or 4, that is, a reception antenna, an RF front end, a bandpass filter, and a demodulator. Here, the function of each component is as described above with reference to FIGS. 2 to 4.

When the first to Nth transmitters 510-1 to 510-N simultaneously transmit signals to reach the receiver 520 at the same time point, or the time points at which these transmitters transmit signals are different, but due to factors such as distance When these signals accidentally reach the receiver 520, the receiver 520 may distinguish these signals. The receiver 520 may restore the user data by classifying these signals by having code information of each signal transmitted from various transmitters or by sharing the code information with multiple transmitters in advance.

Meanwhile, the positions of multiple users, that is, the plurality of transmitters 510-1, 510-2, ..., 510-N, may be irregular, and may transmit data asynchronously to each other. Such asynchronous data transmission may cause multiple access interference (MAI) on the receiver 520 side. Here, the multiple access failure M (t) occurring on the receiver 520 side may be expressed as Equation (5).

Here, K is the total number of active users present in the system, and n (t) is additive white Gaussian noise.

Assuming that the receiver 520 has information about the expected delay and spreading code of the preferred user (ie, the 0th user), all other users except the preferred user (ie, 1) Each signal from the first user to the K-1th user) is regarded as a failure from the perspective of the receiver 520. As a result, the signal waveform received from the receiver 520 may be expressed as Equation (6).

Here, S ⁰ (t) is a signal transmitted by a preferred user, and h ⁰ (t) is a channel impulse response corresponding to S ⁰ (t).

The signal S ⁰ (t) transmitted by the preferred user is correlated to the original signal template to obtain a bit error rate (BER).

6 is a graph showing a simulation result by applying a pseudo-random binary code (PRN) to a nanonetwork communication apparatus according to this embodiment, and FIG. 7 is a nanonetwork communication apparatus according to this embodiment It is a graph showing the results of simulation by applying a simulated annealing code (SA).

6 and 7, simulation parameters are as shown in Table 1.

parameter value Pulse duration (Tp) 2.5 ps Cord length (Nc) 31 Symbol duration (Ts) 80 ps Pulse width parameter 100 fs Number of users causing interference 2-15

6 and 7, simulation results were evaluated using a symbol-energy-to noise ratio (SNR) (E _s / N ₀ ) for BER. Two types of codes having the same length, PRN code and SA code, were used in the simulation. The concentration of water molecules in the channel is 10%, and the number of users causing interference was set from 2 to 15. The distance between users was uniformly changed from 10 μm to 1 m. It is assumed that the transmitters 510-1, 510-2, ..., 510-N and the receiver 520 are completely synchronized, and multiple users transmit and receive data irregularly. The offset interval between multiple users is a specific value selected between 0 and T _p (N-1).

5 to 7, it is confirmed that the performance of the PRN code and the SA code does not show a significant difference in a region with a low SNR (SNR <5 dB). This is due to the high spreading loss in the terahertz band. Accordingly, the receiver 520 cannot distinguish the desired signal. However, as the SNR increases, discernible differences are found. When the number of users is large, that is, when the number of transmitters is large, interference at the receiver 520 is also greater. In addition, high SNR is required to obtain a desired BER despite the small number of users generating interference due to high channel loss in this region. It can be seen that in the region where the SNR is greater than 5 dB, using the PNR code shows better performance than using the SA code.

FIG. 8 is a graph showing performance comparison results when a pseudo-random binary code (PRN) and a simulated annealing code (SA) are applied to a nanonetwork communication device according to the present embodiment. to be.

The graph of FIG. 8 shows the performance of the nanonetwork communication apparatus by applying two different codes when the symbol energy-to-noise ratio (Es / N0) is fixed to 25 dB.

The PRN code performed better than the SA code for all user numbers. This is because the cross-correlation property of the PRN code is better than that of the SA code.

Codes with a low cross correlation characteristic are suitable for minimizing multiple access failures. The criterion used to evaluate the cross correlation characteristic is a peak cross-correlation level (PCCL), where the PCCL of the PRN code represents -5.22 dB, whereas the PCCL of the SA code is -4.25 dB. Was confirmed. It can be seen that the BER characteristic of the PRN code is better than the BER characteristic of the SA code due to the low PCCL characteristic of the PRN code.

9 is a flowchart illustrating a nanonetwork communication method according to the present embodiment.

Since the nano-network communication apparatus according to the present embodiment has been described in detail with reference to FIGS. 2 to 8, descriptions of the overlapped contents will be omitted or simplified.

5 and 9, in step S910, each of the plurality of transmitters 510-1 to 510-N has a pulse having a preset pulse duration and a preset duty cycle. To create. Here, the frequency of the pulse may have a frequency between 0.1 THz and 10 THz. The generated pulse p (t) may be a Gaussian monocycle pulse having a pulse-width of several hundred femtoseconds, and may be expressed as Equation 1 described above.

In step S920, each of the plurality of transmitters 510-1 to 510-N generates a specific code used for generating a modulated signal, for example, a spreading code. At this time, since the specific codes generated are different for each transmitter (that is, the user), the receiver can distinguish signals transmitted from a plurality of transmitters. Further, the spreading code may include a pseudo-random binary code (PRN) and a simulated annealing code (SA).

In step S930, each of the plurality of transmitters 510-1 to 510-N, direct sequence on-off keying: DS-OOK based on the pulse and user data generated in step S910. ) To generate a modulated signal.

In step S940, each of the plurality of transmitters 510-1 to 510-N may transmit a modulated signal generated in step S930 through a terahertz band channel using a transmission antenna.

In this case, the receiver 520 may restore user data after receiving the transmitted modulated signals and demodulating each signal using the same code as a specific code used for modulation of each signal.

Although FIG. 9 describes that each process is executed sequentially, the present invention is not limited thereto. In other words, since the process described in FIG. 9 may be changed or executed or one or more processes may be executed in parallel, FIG. 9 is not limited to a time series sequence.

On the other hand, each step of the flow chart shown in Figure 9 can be implemented as computer-readable code in a computer-readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data readable by a computer system is stored. That is, the computer-readable recording medium includes magnetic storage media (eg, ROM, floppy disk, hard disk, etc.), optical reading media (eg, CD-ROM, DVD, etc.) and carrier waves (eg, the Internet). Storage). In addition, the computer-readable recording medium can be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

The above description is merely illustrative of the technical spirit of the embodiments according to the present invention, and those of ordinary skill in the art to which the embodiments according to the present invention belong do not depart from the essential characteristics of the present embodiments Various modifications and variations will be possible. Therefore, the embodiments according to the present invention are not intended to limit the technical spirit of the present embodiments, but to explain, and the scope of the technical spirit of the present embodiments is not limited by these embodiments. The scope of protection of the embodiments according to the present invention should be interpreted by the following claims, and all technical spirits within the equivalent range should be interpreted as being included in the scope of the embodiments according to the present invention.

100, 200, 400, 500: nano network communication device
110, 210, 410, 510-1, 510-2, 510-N: transmitter
112, 212, 412: pulse generator 114, 214, 414: modulator
115: timing information generator 215, 415: code information generator
116, 216, 416: transmit antenna
120, 220, 420, 520: receiver
122, 222, 422: receiving antenna 124: detector
224, 424: RF front end 225, 425: phase detector
226, 426: Bandpass filter 126, 228, 428: demodulator
229, 429: Code information generator

Claims (9)

As a terahertz band based nano network communication device,
A pulse generator that generates a pulse having a predetermined duty cycle, a modulator that generates a modulated signal by performing DS-OOK modulation using a spreading code on the generated pulse and user data, and tera the modulated signal A transmitter including a transmit antenna transmitting through a Hertz band channel; And
It includes a receiver for demodulating the transmitted modulation signal using the same code as the spreading code,
The receiver,
A signal received from a transmitter other than a specific transmitter whose predicted delay and spreading code information is known is regarded as a failure,
Nano network communication device. According to claim 1,
The duty cycle,
Calculated based on the pulse duration and symbol duration,
Nano network communication device. According to claim 1,
The modulator,
If there is a pulse generated by the pulse generator, allocate a first data bit,
Allocating a second data bit when the pulse generated by the pulse generator does not exist,
Nano network communication device. According to claim 1,
The modulator,
Including the code information generator for generating the spreading code,
Nano network communication device. According to claim 1,
The spreading code,
Pseudo-random binary code (PRN),
Nano network communication device. According to claim 1,
The generated pulse,
A Gaussian monocycle pulse with pulse-width of hundreds of femtoseconds,
Nano network communication device. According to claim 1,
The generated pulse,
Having a frequency of 0.1 to 10 THz,
Nano network communication device. Terahertz band-based nano-network communication method,
Generating a pulse having a predetermined duty cycle;
Generating a modulated signal by performing DS-OOK modulation using a spreading code on the generated pulse and user data; And
And transmitting the generated modulated signal through a terahertz band channel.
The transmitted modulated signal is demodulated using the same code as the spreading code,
Signals transmitted from other transmitters except for specific transmitters for which predicted delay and spreading code information are known are considered as failures.
Nano network communication method. The method of claim 8,
The spreading code,
Pseudo-random binary code (PRN),
Nano network communication method.

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