Performance analysis of Differential Frequency Hopping Communication system over Rician channel

Differential frequency hopping communication system as a new concept of communication systems has become an important development direction of the current shortwave confidential communications. In this paper, on the DFH communication mechanism based on the establishment of a function, the function design m sequences designed based on HHT transform DFH signal detection design, experimental results show that this scheme can effectively achieve DFH Signal generation and detection of a communication system. KEYWORD: DFH; G function; HHT transform; detection International Conference on Social Science, Education Management and Sports Education (SSEMSE 2015) © 2015. The authors Published by Atlantis Press 710 unknown Research hopping signal detection method differential signal parameters under the conditions. 2 BASIC PRINCIPLE OF DFH The concept stems from a DFH enhanced 1995 Sandes company developed Spread Spectrum (Correlated Hopping Enhanced Spread Spectrum, called CHESS) system, CHESS radio with DFH (Differential Frequency Hopping, referred DFH) as the core technology to achieve high-speed frequency hopping, hopping speed up to 5000 hops / sec transfer rate up to 19.2kbit / s, and anti-jamming, strong anti-fading capability. DFH has two key technologies, namely signal detection technology design technology and the receiving end of a differential frequency hopping pattern. DFH system uses a new technology system, its design is based on the hopping pattern called a mathematical relationship of G function, at the sending end, the frequency value of the current time n f is by the frequency value 1 n f  and the current time data symbols n X decision. An implicit difference equation is expressed as [8]: ) , ( 1 n n n X f G f   (1) G(∙)indicates a function transform relations, referred to function. Its frequency, data transformation relationship can be expressed in the form of a diagram of transformation function in Figure 1. Fig.1 The G function transform Differential frequency hopping communication system, the receiver uses a variety of new technology to receive broadband, digital signal processing. At the receiving end, by the broadband receiving digitized, characterized by the FFT analysis of all signals within the bandwidth of the frequency hopping, 1 n f  and n f is determined. Restore the data transmitting side by the inverse transform function, namely: ) , ( 1 1 n n n f f G X    (2) Wherein G -1 denotes inverse transform function of G, which requires the function G must have reversible. Its inverse transform relationship can be expressed in the form of a diagram 2. Fig.2 The inverse G function transform 3 G FUNCTION ALGORITHM PRINCIPLE In the differential frequency hopping, G function is a specific frequency transfer function, can be seen as a directed graph, directed graph node represents a frequency point of each frequency set, each node separates 2 f  branches, BPH representative of the number of bits per hop transmission, also called the fan-out coefficients. Are marked on each bifurcation current information symbols to the set of frequencies containing frequencies of 64, for example, when each hop transmission 1bit, each node has two bifurcated (0,1). BPH transmission bit stream bits per symbols constituting a transmission symbol stream according to a given differential frequency hopping sequence with a frequency corresponding to the generated map. 3.1 1 bit G function design G function design approach are many, including those based on the theory of congruence G function design, based on the state of the shift register design function G, G function m-sequence-based design and so on. In this selection of designs based on G function m sequences. Algorithm is described as follows: Step1 First reads the data n X to be transmitted, the data is encoded, the encoded data n d is calculated.

This paper proposes a Frequency Hopping (FH) communication system with a novel frequency synthesis method. Considering that the existing frequency synthesis methods are inevitably limited by the electronic device bandwidth, a combination of directly modulated laser (DML) and optical heterodyne technique is proposed as a hopping frequency source. The principle of the method is presented and a dual frequency hopping system in E band is carried out through simulation to verified the feasibility of the proposed method. This frequency synthesis method supports high radio frequency, ultra-wideband and high hopping speed.

The integrated design for both radar and anonymous communication has drawn more attention recently since wireless communication system appeals to enhance security and reliability. Given the frequency hopping (FH) communication system, an effective way to realize integrated design is to meet the spectrum compatibility between these two systems. The paper deals with a unimodular sequence design technique which considers optimizing both the spectrum compatibility and peak sidelobes levels (PSL) of auto-correlation function (ACF). The spectrum compatibility requirement realizes anonymous communication for the FH system and provides this system lower probability of intercept (LPI) since the spectrum of the FH system is hidden in that of the radar system. The proposed algorithm, named generalized fitting template (GFT) technique, converts the sequence optimization design problem to a iterative fitting process. In this process, the power spectrum density (PSD) and PSL behaviors of the generated sequences fit both PSD and PSL templates progressively. Two templates are established based on the spectrum compatibility requirement and the expected PSL. As noted, in order to ensure the communication security and reliability, spectrum compatibility requirement is given a higher priority to achieve in the GFT algorithm. This algorithm realizes this point by adjusting the weight adaptively between these two terms during the iteration process. The simulation results are analyzed in terms of bit error rate (BER), PSD, PSL, and signal-interference rate (SIR) for both the radar and FH systems. The performance of GFT is compared with SCAN, CAN, FRE, CYC, and MAT algorithms in the above aspects, which shows its good effectiveness.

Anti-follower jamming wide gap multi-pattern frequency hopping communication method

Compared with common jamming techniques, the correlated jamming is much efficient against the frequency hopping (FH) communication system. Because of the similarity between the correlated jamming signal and the FH signal, it is very difficult for common anti-jamming techniques to deal with such correlated jamming. According to the independence between the payload of the correlated jamming signal and the victim FH signal, a novel independent component analysis (ICA) based receiver is proposed in this paper. Two antennas are introduced at the receiver end. The received signals are despread firstly to reduce the dimension of mixing matrix. Then ICA is utilized to recover the useful signal from two baseband signals. The numerical simulation results indicate that the proposed ICA-based receiver is robust to the correlated jamming. Even when the power of correlated jamming is very strong, the proposed receiver can still improve the BER performance greatly.

This paper discusses the multiple access performance of the spread spectrum modulation called differential frequency hopping (DFH) and its associated signal processing algorithms, and compares DFH performance to the performance of fast frequency hopping (FFH) multiple access systems. To fairly compare FFH and DFH, it is necessary to carefully choose the parameters for each system, using the concept of efficiency. The single-user efficiency provides a fair way to set parameters when comparing FFH and DFH systems when there is no multiuser interference (MUI) present. We develop the multi-user efficiencies for the two waveforms, as a mechanism to determine comparable system parameters for FFH and DFH multiple-access systems. It is shown that, for the same bits/symbol, the data rate of a single-user DFH is larger than the FFH data rate if the hop dwell time is the same DFH is shown to be significantly more MUI-tolerant than the comparable FFH and FFH systems with interference cancellation, particularly at low and mid-level SNRs. Similarly, the theoretical same-efficiency DFH outperforms the non-optimal FFH at most SNRs and outperforms optimal FFH with collision resolution at SNRs above 7 to 11 dB, depending on the number of simultaneous users. The theoretical and simulation results consistently indicate that DFH is more MUI-tolerant than FFH for the same efficiency, which is desirable in ad hoc networks with multiple users.

In this paper, an expression for asymptotically tight theoretical upper bound on bit error rate (BER) of differential frequency hopping (DFH) system over Rician fading channels with additive white Gaussian noise (AWGN) and partial-band noise jamming (PBNJ) is derived. By comparing the BER between theory and simulation, we note that the difference obtained from the upper bound and the simulation result decreases rapidly as BER decreases, in fact, at BER not larger than 1 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> , the numerical result along with the simulation curve tightly. We also get the conclusion that the bandwidth of the worst-case PBNJ is jamming a frequency and the BER decreases as Rician K factor increases from the results.

Differential Frequency Hopping(DFH) is a new frequency-hopping spread spectrum system, DFH is the core technology of CHESS radio, now mainly used in short-wave communications, which mainly come down to a G function algorithm, this set of G functions merge information modulation and Frequency hopping patterns together. Based on the traditional of G function, this article Proposed an improved method of 4 bit G Functions, the introduction of a strong error correction capability RS code control a subset of frequency hopping, and its been tested. The results show that the algorithm generated frequency hopping patterns with good randomness and uniformity.

In application, frequency-hopping (FH) communication system often suffers various interferences, such as single frequency narrow-band interference, partial band blocking interference and tracking interference, and so on. For all that, by using optimal Wide-Gap (WG) FH sequences, FH communication system can significantly improve the anti-interference performances. In this paper, the relations between WG FH sequence theoretic bounds published in the journal IEEE Access (Peihua Li et al., 2019) are first made clear, and then five types of generalized methods are presented to design new classes of WG FH sequence sets. It is shown that all designed WG FH sequence sets are optimal according to the bound derived by Peihua Li &lt;italic&gt;et al.&lt;/italic&gt; And by selecting appropriate original sequence sets, many of the optimal WG FH sequence sets can be obtained by our methods. Most importantly, these WG FH sequence sets have new parameters that are not covered in the literature.

Differential frequency hopping (DFH) is believed to have great potential in increasing the data rate of shortwave communication. Recent studies show that DFH suffers from an inherent serious drawback that its frequency transition matrix may be intercepted by any third-party receiver. This would heavily damage the anti-jamming performance of DFH. The root of this drawback is that differential frequency hopping sequence is not PN sequence but Markov chain. The invariant correlation between successive hops makes interception possible by statistically analyzing the intercepted DFH sequence. In this paper, we put forward a novel method named FH-DFH to deal with this problem. The basic idea of our method is to eliminate correlation between successive frequency hops by combining DFH with conventional FH technique. Analytical and simulation results show that DFH system using our method exhibits better anti-interception performance than not only normal DFH system but also oTVG-DFH system.

The synchronization is one of the key techniques in frequency hopping communication system. In this paper, a new synchronization scheme for high-speed frequency hopping is analyzed after analyzing synchronization in conventional frequency hopping communication system. Based on the method combined synchronization-head with time of day (TOD), the synchronization information is carried by slow-hopped pattern, and the corresponding message is carried by fast-hopped pattern, which overcomes the difficulty of correlation code transmission in fast frequency hopping. This paper mainly studies the frame of synchronization head,the synchronization of FH pattern. The performance of synchronization is analyzed and the simulation is completed by using Matlab7.0. The performance of synchronization shows that the scheme has the advantages of short synchronization time, higher probability of capture and lower false probability.

The follower jamming has a strong threat to the Frequency Hopping (FH) communication. Before the follower jamming is suppressed, the correct recognition of follower jamming should be completed. In this paper, the Frequency Hopping-Gaussian filtered minimum shift keying (FH-GMSK) communication system is adopted as the carrier to research the follower jamming recognition of FH communication system. The automatic recognition of the follower jamming in the FH communication system is proposed by a set of feature parameters which are robust and insensitive to the jamming to signal ratio (JSR). This feature parameters can jointly extract the characteristics of the follower jamming in time, frequency and time-frequency at the conditions of no prior knowledge of the follower jamming. The simulated result shows that the correct recognition rate in FH communication system of the common follower jamming signals based on the method proposed in the reasonably high in the different JSR.

The application of Low Density Parity Check (LDPC) code in the anti-interference systems has drawn an increasing attention, due to its admiring performance which is very close to the theory limit. This paper focuses on a LDPC encoded slow frequency hopping (SFH) communication system with partial-band interference. Firstly, a modified soft- decision algorithm based on the utilization of interference information is proposed, and its performance is compared with some other soft-decision methods. Secondly, with numerical simulation, the influence of code rate, code length and the number of symbols per hops on the performance of the system with partial band noise interference is illustrated and examined in detail. Considering the great influence of hops per symbol on the performance, interleaver should be used and its influence on the performance is further examined by simulation. Finally, some constructive advises for the design of LDPC coded SFH system are given. Simulation results show that, with a reasonable design, the SFH system with LDPC code could achieve a desirable performance.

It is difficult to ensure stability and communication efficiency of traditional anti-jamming frequency hopping communication system in the frequency domain probabilistic jamming environment. Therefore, this paper proposes an adaptive frequency hopping communication scheme under probabilistic jamming. Based on the probabilistic jamming model, the practical frequency hopping (FH) strategy and average payoff is obtained using Q-Learning algorithm and is compared with the theoretical optimal average payoff obtained by the greedy algorithm. Simulation results show that our proposed algorithm is fast to converge, has fewer frequency hops compared with existing anti-jamming FH strategy, and the average payoff is close to the theoretical optimal frequency hopping strategy.

In today’s information age, how to carry out the accurate information communication is a crucial issue in the field of communication, which is widely used in civil and military fields. Frequency hopping communication system is a typical spectrum communication system, it is in military communication, mobile communication, computer wireless data transmission and wireless LAN and other fields have a very wide range of applications, has become the current short wave communication is one of the important development directions. In this paper, we introduce a design of frequency hopping communication system based on Matlab. Through the frequency hopping communication system the simulation research and theoretical analysis, to achieve the desired results.