Shen Dongya

A Triple-Band Microstrip Antenna for WLAN Applications

A novel compact triple-band monopole microstrip antenna for WLAN applications is proposed. The proposed antenna is made up of two one-quarter wavelength resonating components, fed by a 50ohmic microstrip line. The configuration is simple. The resonating frequencies of the proposed antenna are 2.5GHz and 4.8GHz, respectively, the bandwidth is about 500MHz (2.25~2.75GHz) and 2.63GHz (3.82~6.45GHz) (return loss less than -10dB), covering the triple bands of WLAN system. The lower and higher resonant frequencies can be easily tuned by adjusting a few parameters of the presented antenna. This antenna satisfies the requirements of wireless local area network(WLAN) 802.11(2.4~2.484GHz, 5.15~5.35GHz, 5.725~5.825GHz) applications. The softwares of Ansoft HFSS11 and CST Microwave Studio are used to simulate and optimize the antenna.

The six-state Markov model for land mobile satellite channels

A new channel model with a six-state Markov chain for the land mobile satellite channel is presented. The received amplitude series were classified into two different states according to the degree of shadowing experienced, and both states have three sub-states. The two-state model, the Lutz distribution (Rice+Rayleigh+Log-normal), is extended to the new six-state model in this paper under the different time-share of shadowing. Comparison of the first- and the second-order statistics of the proposed model with the measured data demonstrate the flexibility of the model in characterizing a variety of channel conditions and propagation mechanisms over satellite links.

A new Five-State Markov model for land mobile satellite channels

A new channel model with a five-state Markov chain for land mobile satellite channel (LMSC) is presented. The received amplitude series were classified into three different states according to the degree of shadowing experienced. The two-state model and three-state model are extended to the new five-state model in the paper under the different time-stare of shadowing. The first and second order statistics characters of the model are compared with the measured data and simulation. Finally, the average BER of five-state Markov is compared with six-sate Markov model.

Theoretical analysis and simulation of the outage probability for six-state Markov model on land-mobile satellite channels

An analytical technique well suited to numerical analysis is presented for computing the average outage probability of binary phase-shift keying (BPSK) and binary differential phase-shift keying (DPSK) in the land-mobile satellite channel (LMSC). The close-loop formulas are found for not using diversity and L-branch micro-diversity using maximal ratio combining (MRC). Following previous empirical studies, the LMSC is modelled as a six-state Markov model. Using measurement channel parameters, the performance in mobile environment for six-state Markov model is found.

The simple channel capacity estimation for MIMO wireless channels

In this paper, a simple approximate technique for analyzing the ergodic capacity of independent and identically distributed (i.i.d) Rayleigh fading MIMO channels is presented by using the asymptotic capacity rate of MIMO channels. The method excludes any integrations and special functions. The simulation results are compared with analytic method and good agreement is reported.

An improved method about AES and FPGA high-speed realize

It is difficult to design to generate a S box with excellent crytographic properties in AES algorithms. So Wu Wenling et al. proposed a new S box. The paper is based on the new S box to realize extension from one set to multiple sets of S boxes by utilizing S box to generate time-shift selection function. And employ the dynamic S box of encryption and decryption scheme to AES advanced encryption algorithm. Then, design the S box on the FPGA platform. The simulation confirms that the method improves the speed of the encryption algorithm and reduces hardware logic unites of the encryption algorithm.