처프 대역 확산 시스템에서 처프율 부정합에 따른 성능 분석

김기태,김광열,신요안 한국통신학회 2023 韓國通信學會論文誌 Vol.48 No.11

We analyze the effect of chirp rate mismatch on chirp spread spectrum systems. Since orthogonality between transmission signals must be guaranteed in chirp-based communications, a study has been conducted using multiple linear chirps. On the other hand, in order to obtain a dominant position over the enemy in electronic warfares, a technique capable of improving not only communication performance but low probability of interception performance, is required. Therefore, in this paper the multiple linear chirps are considered, and the low probability of interception performance is analyzed and compared to the single linear chirp counterpart through simulations according to chirp rate mismatch.

Packet-Reduced Ranging Method with Superresolution TOA Estimation Algorithm for Chirp-Based RTLS

오대건,고승열,정정화 한국전자통신연구원 2013 ETRI Journal Vol.35 No.3

In this paper, a packet-reduced ranging method using a superresolution time of arrival estimation algorithm for a chirp-based real-time locating system is presented. A variety of ranging methods, such as symmetric doublesided two-way ranging (SDS-TWR), have been proposed to remove the time drift due to the frequency offset using extra ranging packets. Our proposed method can perform robust ranging against the frequency offset using only two ranging packets while maintaining almost the same ranging accuracy as them. To verify the effectiveness of our proposed algorithm, the error performance of our proposed ranging method is analyzed and compared with others. The total ranging performance of TWR, SDSTWR, and our proposed TWR are analyzed and verified through simulations in additive white Gaussian noise and multipath channels in the presence of the frequency offset.

Unscented 칼만 필터 기반의 chirp spread spectrum 노드 위치 추정

조현우(Hyeonwoo Cho),반성준(Sung Jun Ban),이영훈(Younghun Lee),전용주(Youngju Joen),김상우(Sang Woo Kim) 대한전기학회 2009 정보 및 제어 심포지엄 논문집 Vol.2009 No.5

Position estimation in indoor is significant problem, because GPS which is usually used for outdoor positioning cannot be utilized to indoor positioning. Sensor network can be a solution for the positioning. Recently, chirp spread spectrum (CSS) specified in IEEE 802.15.4a provides an ability of ranging. Based on the results of the ranging, a position of a C55 node can be calculated by using trilateration. In this case, Kalman filter can be applied to the trilateration because of the measurement noise. In this paper, we apply the unscented Kalman filter for the trilateration. The trilateration can be represented to a nonlinear state space equation, and the unscented Kalman filter is suitable for nonlinear state space equation. Through the experimental results. we show the accuracy of the estimated position.

정합필터 기반의 Chirp Spread Sprectrum을 위한 새로운 주파수 오프셋 추정 알고리즘

김영삼(Yeong-Sam Kim),정정화(Jong-Wha Chong) 大韓電子工學會 2010 電子工學會論文誌-TC (Telecommunications) Vol.47 No.10

본 논문에서는 정합필터 기반의 IEEE 802.15.4a chirp spread spectrum (CSS) 을 위한 새로운 주파수 오프셋 추정 알고리즘을 제안한다. 기존의 주파수 오프셋 추정 알고리즘은 연속되는 동일한 심볼 간의 차등 위상을 계산함으로서 주파수 오프셋을 추정하였다. 하지만 CSS 는 긴 십볼 구간과 가드 구간을 포함하고 있어 기존의 방법으로 주파수 오프셋을 추정하였을 경우 위상 모호성이 발생한다. 특히 정합필터 기반 수신기 구조에서 위상 모호성을 해결하지 않는다면 주파수 오프셋에 의한 정현파 간섭 현상으로 정합필터의 성능이 감소하게 된다. 따라서 본 논문에서는 위상 모호성을 해결하기 위해 정수부와 소수부 주파수 오프셋 추정을 분할화 하여 주파수 오프셋을 추정하는 새로운 알고리즘을 제안한다. 제안하는 알고리즘은 sub-chirp간 정합필터 결과의 차등 위상을 계산 한 결과와 기존의 심볼 간 차등 위상 정보를 이용하여 정수부 주파수 오프셋을 추정하여 위상 모호성을 제거 한 후, 심볼 간 차등위상 정보를 통하여 소수부 주파수 오프셋을 추정한다. 시뮬레이션 결과 제안하는 알고리즘은 정수부 주파수 오프셋 추정을 통해 위상 모호성 문제를 해결할 수 있음을 확인하였고 위상 모호성이 발생하지 않는 경우에서도 기존의 알고리즘과 거의 동일한 성능을 보임을 확인하였다. A new frequency offset estimation algorithm for chirp spread spectrum based on matched filter is proposed. Generally, the differential phase between successive symbols is used for the conventional frequency offset estimation algorithm. However, if the conventional frequency offset estimation algorithm is used for CSS, phase ambiguity arises because of long symbol duration and guard time. The phase ambiguity causes performance degradation of matched filter since the received signal is corrupted by the integer frequency offset. In this paper, we propose a new frequency offset estimation algorithm which separates integer and fractional frequency offset estimation for removing the phase ambiguity. The proposed algorithm estimates the integer frequency offset by using differential phase between matched filtering results of sub-chirps and successive symbols. Then, the fractional frequency offset is estimated by using the differential phase between successive symbols Simulation results show that the proposed algorithm well removes the phase ambiguity, and have almost same estimation performance compared with conventional one when there is not the phase ambiguity.

IEEE 802.15.4a Chirp SpreadSpectrum을 위한 저복잡도 수신기 구조

김영삼(Yeong-Sam Kim),정정화(Jong-Wha Chong) 大韓電子工學會 2010 電子工學會論文誌-TC (Telecommunications) Vol.47 No.8

본 논문에서는 IEEE 802.15.4a chirp spread spectrum (CSS) 를 위한 저복잡도 수신기 구조를 제안한다. 무선 통신 시스템에서는 일반적으로 수신기의 신호 수신시 최대 SNR (Signal to Noise power Ratio) 을 보장하는 정합필터를 사용하여 신호를 복조를 하는 것이 일반적이다. 하지만, 정합필터는 하드웨어 복잡도가 높아 저복잡도, 저가격의 센서 네트워크를 목적으로 하는 CSS에서는 적합하지 않다. 따라서 본 논문에서는 정합필터를 사용하지 않고 인접 심볼 간 차등 곱셈과 누적을 통하여 chirp 신호를 복조하는 새로운 수신기 구조를 제안한다. 또한, CSS에 사용되는 이원 직교 코드의 특성을 이용하여 곱셈기를 사용하지 않은 이원 직교 디코더 구조를 제안한다. 제안하는 수신기 구조는 정합필터 기반 구조에 비하여 BER (Bit Error Rate) 성능은 떨어지지만 하드웨어 구현을 위한 곱셈기, 가/감산기, 레지스터 등의 자원의 수를 절감하였다. A receiver architecture with low complexity for chirp spread spectrum (CSS) of IEEE 802.15.4a is proposed. To demodulate the received signal at the highest signal to noise power ratio, matched filter is generally adopted for the receiver of wireless communication systems. It is, however, not resonable to adjust the matched filter to the receiver of CSS whose objectives are low complexity, low cost and low power consumption since complexity of the matched filter is high. In this paper, we propose a new receiver architecture using differential multiplication and accumulator not matched filter for demodulation. Also, bi-orthogonal decoder implemented by only adder/subtractor is proposed. The hardware resources for implementation are reduced in the proposed receiver architecture, although bit error rate performance is low compared with the receiver architecture based on the matched filter.

A Mitigation of Multipath Ranging Error Using Non-linear Chirp Signal

Jin-Ik Kim,Moon-Beom Heo,Gyu-In Jee 대한전기학회 2013 Journal of Electrical Engineering & Technology Vol.8 No.3

While the chirp signal is extensively used in radar and sonar systems for target decision in wireless communication systems, it has not been widely used for positioning in indoor environments. Recently, the IEEE 802.15.4a standard has adopted the chirp spread spectrum (CSS) as an underlying technique for low-power and low-complexity precise localization. Chirp signal based ranging solutions have been established and deployed but their ranging performance has not been analyzed in multipath environments. This paper presents a ranging performance analysis of a chirp signal and suggests a method to suppress multipath error by using a type of non-linear chirp signal. Multipath ranging performance is evaluated using a conventional linear chirp signal and the proposed non-linear chirp signal. We verify the feasibility of both methods using two-ray multipath model simulation. Our results demonstrate that the proposed non-linear chirp signal can successfully suppress the multipath error.

A Mitigation of Multipath Ranging Error Using Non-linear Chirp Signal

Kim, Jin-Ik,Heo, Moon-Beom,Jee, Gyu-In The Korean Institute of Electrical Engineers 2013 Journal of Electrical Engineering & Technology Vol.8 No.3

While the chirp signal is extensively used in radar and sonar systems for target decision in wireless communication systems, it has not been widely used for positioning in indoor environments. Recently, the IEEE 802.15.4a standard has adopted the chirp spread spectrum (CSS) as an underlying technique for low-power and low-complexity precise localization. Chirp signal based ranging solutions have been established and deployed but their ranging performance has not been analyzed in multipath environments. This paper presents a ranging performance analysis of a chirp signal and suggests a method to suppress multipath error by using a type of non-linear chirp signal. Multipath ranging performance is evaluated using a conventional linear chirp signal and the proposed non-linear chirp signal. We verify the feasibility of both methods using two-ray multipath model simulation. Our results demonstrate that the proposed non-linear chirp signal can successfully suppress the multipath error.

부분대역 잡음 재밍 환경에서 주파수 도약 처프 대역 확산 시스템의 전송 성능 분석

이명로,김광열,신요안 한국통신학회 2022 韓國通信學會論文誌 Vol.47 No.10

Partial band noise jamming is a method of jamming a portion of the transmission bandwidth. In this case, the spread spectrum technique is used to improve anti-jamming performance. In this paper, we consider a frequency-hopping chirp spread spectrum technique that fuses the frequency-hopping spread spectrum scheme and the chirp spread spectrum scheme, and analyze the transmission rate and the anti-jamming performance according to the cross correlation coefficient of chirp signals. Simulation results show that the proposed method can improve transmission rates or anti-jamming performance depending on the operational purpose. 부분대역 잡음 재밍은 전송 대역폭 중 일부분을재밍하는 방식으로, 이에 대한 항재밍 성능을 향상시키기 위해 대역 확산 기술이 사용된다. 본 논문은 대역 확산 기술인 주파수 도약 대역 확산 방식과 처프대역 확산 방식을 융합한 주파수 도약 처프 대역 확산 기법을 고려하고, 처프 신호의 상호상관계수에 따른 전송률과 항재밍 성능을 분석한다. 모의실험 결과, 제안된 방식이 운용 목적에 따라 전송률을 향상시키거나, 항재밍 성능을 향상시킬 수 있음을 보였다.

수중 통신을 위한 일반화된 처프 대역 확산 기법

한상만(Sangman Han),김진원(Jinwon Kim),서보근(Bogeun Seo),이호준(Hojun Lee) 호서대학교 공업기술연구소 2024 공업기술연구 논문집 Vol.43 No.1

본 논문에서는 chirp spread spectrum (CSS) 기법의 전송률을 높이기 위해서 다양한 변조 차수를 가질 수 있는 generalized-CSS (G-CSS) 기법을 제안한다. 기존의 CSS 기법은 상향 처프 또는 하양 처프로 변조하는 방법으로 제한적인 변조차수를 가지기 때문에 전송률이 낮다는 한계를 가지게 된다. 제안하는 G-CSS 기법은 심볼의 시작 및 끝 시점에 대해 서로 다른 변조 차수에 따라 주파수 빈을 설정하고, 전송하고자 하는 비트에 따라 시작 주파수와 끝 주파수로 끝나는 처프 신호를 할당하여 변조한다. 제안한 G-CSS 기법은 다양한 변조 차수로 설계가 가능하며 시스템에서 요구하는 전송률에 따라 신호를 설계하여 전송할 수 있다. 전산 모의실험을 통해 기존의 기법과 제안한 기법이 동일한 전송률을 가칠 때에 통신 성능을 분석하였으며 제안한 방법이 기존의 방법보다 bit error rate (BER) 성능의 결과가 약 2배 성능이 향상된 것을 보였다. This paper proposes a generalized-chirp spread spectrum (G-CSS) modulation scheme, which is able to adjust various modulation orders to increase transmission rate of the conventional chirp spread spectrum (CSS). The conventional CSS uses up-chirp or down-chirp for modulation, which have limited modulation orders, resulting in a lower transmission rate. The proposed G-CSS sets frequency bins according to different modulation orders at the start and end points of the symbol. It modulates by assigning a chirp signal with assigned start and end frequencies based on the bits to be transmitted The proposed G-CSS can be designed with various modulation orders, allowing the system to be tailored to meet the required transmission rates. Through computational simulations, the bit error rate (BER) performances of the proposed G-CSS were compared with the conventional CSS with the same transmission rate, and the BER performances of the proposed G-CSS had twice better than that of the conventional CSS.

NED를 사용하는 FH-CSS(Frequency Hopped - Chirp Spread Spectrum)의 항 재밍 성능 분석

김성호,김영재,황석구,조병각,신관호,김남,Kim, Sung-Ho,Kim, Young-Jae,Hwang, Seok-Gu,Jo, Byoung-Gak,Shin, Kwan-Ho,Kim, Nam 한국군사과학기술학회 2011 한국군사과학기술학회지 Vol.14 No.1

In the defence wireless communications, conventional Anti-Jamming techniques(Frequency Hopping/Spread Spectrum or Direct Sequence/Spread Spectrum) are used to overcome a intentional interfering signals which are single/multitone or partial band jammer etc. DS/SS techniques is very strong on tone jamming signal but not to be on a partial band jammer. So FH/SS AJ performances are expected method of an substitution of DS/SS, however FH/SS could not have good performance on some BMTJ(Band Multi-tone Jammer). So this paper proposes FH-CSS (Frequency Hopped - Chirp Spread Spectrum) to get more robustness against jammers(BMTJ, PBNJ) and analyze the AJ performances.