This paper proposes and tests in practice a new application design for browser-based streaming. Various streaming-related technologies are made possible under HTML5. This study measures the bounds of throughput which HTML5 applications can expect to achieve in practice.
Contention-based bandwidth request (BR) mechanism in wireless networks is suggested for users with ad-hoc connectivity to support best effort services at affordable cost. In this letter, we develop failure aware contention mechanisms when message and code based signaling mechanisms are carried out on a link with three-hop. The stations perform contention with dynamic update of contention window from the model developed through appropriate failure events of a link. Attributes that influence the contention BR are analyzed through the developed model. The proposed model is validated by means of numerical results.
Reduction of cross polarization in higher frequency is performed for a circularly polarized broadband antenna consisting of a waveguide and an L-shaped feed probe. Cross polarization over a wide elevation range was enhanced in higher frequency beyond the cutoff frequency of first higher order mode in the previously proposed structure. To reduce the cross polarization, the surface of a short wall of the waveguide is modified to be curved parabolically. And, coefficients of the parabolic function for the short wall are optimized to provide the ideal amplitude ratio characteristics. As a result, cross polarization is reduced by 5dB to 10dB using the short wall.
We propose a novel data bandwidth reduction method based on wireless resource allocation for digitized radio over a TDM-PON system. The proposed method reduces the sampling frequency of each BBU-RRU link with minimal degradation in wireless signal quality and the provision of a statistical multiplexing gain. Simulations show that the required PON bandwidth is reduced by 30% when there are 68 mobile terminals.
In short-range multi-input and multi-output (SR-MIMO) transmission, a simple decoding method using an analog radio-frequency (RF) weighting circuit is useful for reducing signal processing complexity in MIMO decoding. With such a method, however, phase and amplitude errors in the weighting circuit may degrade transmission capacity. This paper quantifies the capacity degradation caused by such errors. We believe the results obtained are useful for clarifying SR-MIMO weight error tolerance.
Authors have been analyzed the L-shaped folded monopole antenna (LFMA) numerically and experimentally, and the size of the antenna is smaller compared to planar inverted-F antenna (PIFA) which has similar bandwidth. In this study, we investigated multi-resonance characteristic of LFMA by using a parasitic element in order to realize wideband operation. As a result, wideband characteristic approximately 26% (|S11|≤-10dB) was achieved, which was about double bandwidth before adding the parasitic element (14%). The total antenna volume was maintained due to the configuration of the parasitic element.
Two-dimensional RFID reader pad is proposed using free access transmission line. This pad has stable coupling in arbitrary direction of receiving antenna by a circular polarized receiving element and a diamond shaped transmission line. This paper presents a prototype reader pad and its characteristics.
In recent years, Photonic Crystals (PCs) are widely applied in microwave engineering, antenna engineering and so on. Properties of PCs are often analyzed by the FDTD method. Propagation modes of PCs are one of the important properties. However, FDTD method cannot distinguish degenerate or non-degenerate mode due to its calculation procedure. This paper proposed a classification technique of the degenerate and non-degenerate mode in the FDTD analysis of PCs using a group theory.
Medium Access Control (MAC) is an important aspect of implementing a cognitive radio network. Ghasemi and Razavizadeh proposed a simple, elegant and efficient MAC protocol for cognitive wireless networks . However, the Ghasemi’s algorithm does not consider the quality of the wireless channel in the decision process. In this paper, an improvement in Ghasemi’s algorithm is proposed to consider the behavior of the wireless channel in the decision process.
Sampling frequency offset (SFO) synchronization is one of the very important issue in the orthogonal frequency division multiplexing (OFDM) based digital terrestrial television broadcasting (DTTB) system. The SFO can cause an intersymbol interference and an intercarrier interference that may degrade the performance of an OFDM system. In this paper, we propose a frequency-domain sampling frequency offset estimation method for OFDM based DTTB systems. Computer simulation shows that the proposed sampling frequency offset estimation can improve BER performance with lower complexity compared to the conventional method.