Dynamic bandwidth allocation for multimedia traffic with rate guarantee and fair access in WCDMA systems

Packet scheduling in a WCDMA system poses a new challenge due to its nature of variable bit rates and location-dependent, time-varying channel conditions. In this work, three new downlink scheduling algorithms for a WCDMA base station are proposed to support multimedia transmissions. Using a credit management and a compensation mechanism, our algorithms provide rate guarantee and fair access to mobile terminals. In particular, we propose to allow a user to simultaneously use multiple OVSF codes in a time-sharing manner, which we call a multicode, shared model. Using multiple codes allows us to compensate those users suffering from bad communication quality or even errors. The proposed schemes can tolerate a multistate link condition (compared to the typically assumed two-state, or good-or-bad, link condition) by adjusting the number of OVSF codes and the spreading factor of each code. Simulation results show that the proposed schemes do achieve higher bandwidth utilization while keeping transmission delay low.     

I-WAP: an intelligent WAP site management system

The popularity regarding wireless communications is such that more and more WAP sites have been developed with wireless markup language (WML). Meanwhile, to translate hypertext markup language (HTML) pages into proper WML ones becomes imperative since it is difficult for WAP users to read most contents designed for PC users via their mobile phone screens. However, for those sites that have been maintained with hypertext markup language (HTML), considerable time and manpower costs will be incurred to rebuild them with WML. In this paper, we propose an intelligent WAP site management system to cope with these problems. With the help of the intelligent management system, the original contents of HTML Web sites can be automatically translated to proper WAP content in an efficient way. As a consequence, the costs associated with maintaining WAP sites could be significantly reduced. The management system also allows the system manager to define the relevance of numerals and keywords for removing unimportant or meaningless contents. The original contents will be reduced and reorganized to fit the size of mobile phone screens, thus reducing the communication cost and enhancing readability. Numerical results gained through various experiments have evinced the effective performance of the WAP management system.     

Facilitation of consumer loyalty toward branded applications: The dual-route perspective

Although many brands develop mobile applications (apps) to build relationships with consumers, most branded apps fail to retain consumers’ loyalty. This study examines the facilitation of consumer loyalty toward branded apps (continuance intention, in-app purchase intention, and word-of-mouth intention) from the dual-route perspective. One route is the affective (relationship) route, where brand benefits (functional benefits, experiential benefits, symbolic benefits, and monetary benefits) drive parasocial interactions between consumers and the brand, which, in turn, influences branded app loyalty. The other route is the utility route, where system characteristics (system quality and information quality) affect perceived usefulness, which, in turn, facilitates branded app loyalty. An online survey was conducted, and the research model was empirically tested using partial least squares structural equation modeling. The findings support the dual-route perspective according to which both affective and utilitarian paths facilitate branded app loyalty. The key theoretical contribution of this study is that it moves beyond the utilitarian path and finds the affective (relationship) path to give a more complete picture of the facilitation of consumer loyalty in the branded app context. A strategy is provided to suggest to practitioners how to design branded apps to facilitate consumer loyalty.     

Resource Reuse for D2D Communication in LTE Networks by Efficient Grouping

Wireless Personal Communications - Device to device (D2D) communication is a key technology of 5G mobile communications. It allows devices to communicate by using direct links, rather than...     

Smooth side-match classified vector quantizer with variable blocksize

Although the side-match vector quantizer (SMVQ) reduces the bit rate, the image coding quality by SMVQ generally degenerates as the gray level transition across the boundaries of the neighboring blocks is increasing or decreasing. This study presents a smooth side-match method to select a state codebook according to the smoothness of the gray levels between neighboring blocks. This method achieves a higher PSNR and better visual perception than SMVQ does for the same bit rate. Moreover, to design codebooks, a genetic clustering algorithm that automatically finds the appropriate number of clusters is proposed. The proposed smooth side-match classified vector quantizer (SSM-CVQ) is thus a combination of three techniques: the classified vector quantization, the variable block size segmentation and the smooth side-match method. Experimental results indicate that SSM-CVQ has a higher PSNR and a lower bit rate than other methods. Furthermore, the Lena image can be coded by SSM-CVQ with 0.172 bpp and 32.49 dB in PSNR.     

Stable IIR notch filter design with optimal pole placement

This paper presents a two-stage approach for designing an infinite impulse response (IIR) notch filter. First, the numerator of the transfer function of the IIR notch filter is obtained by placing the zeros at the prescribed notch frequencies. Then, the denominator polynomial is determined by using an iterative scheme in which the optimal pole placements are found by solving a standard quadratic programming problem. For stability, the pole radius in the single notch filter design is specified by the designer, and in the multiple notch filter design, the pole radius is constrained by using the implications of Rouche's theorem. Examples are included to illustrate the effectiveness of the proposed techniques     

A fast video-on-demand broadcasting scheme for popular videos

Broadcasting is a prospective approach to support near video-on-demand services with light communication overhead. By letting clients share channels, such approaches involve partitioning a video into segments and repeatedly broadcasting these segments in multiple channels. An early paper proposed a broadcasting scheme called RFS (recursive frequency splitting), which can significantly reduce clients' waiting time. While efficient, RFS suffers from a high computational complexity of O(nlogn), where n is the number of segments of the video, which is typically very large. This paper proposes an efficient segmentation scheme, which can significantly reduce the computational overhead by slightly sacrificing the number of segments that can be arranged as compared to RFS.     

A Fiber Splicing-Plane-Inspection Technique Using Lens–Fiber Interference for the Cascaded Fiber Fabrication

In this paper, a novel inspection technique for the cascaded fiber fabrication is proposed to improve the coupling performance of such fibers. Instead of using a direct-monitoring method, an indirect technique with the help of the ray tracing and the lens-fiber interference is used. By calculating the optical-path length of the light rays passing through the fiber, the interference fringes and light intensity can be counted. Then, the splicing plane of the cascaded fiber can be determined by observing the difference between the two fiber sections. Simulations and experiments have been performed to find the splicing plane. Finally, the accuracy of fabrication can be improved from 10 to about 1 mum; thus, the coupling loss due to the fabrication process can be reduced.     

Wide-band balun using composite right/left-handed transmission line

A wide-band balun is developed using a composite right/left-handed (CRLH) transmission line (TL) at 2 GHz. It is composed of a Wilkinson power divider and two phase-adjusting transmission lines, namely the CRLH TL and the conventional TL. The input reflection coefficient is better than -10 dB from 1 to 4 GHz. Over the frequency range of 1.24-3.58 GHz, an amplitude imbalance of less than 0.7 dB and a phase error of less than plusmn10deg have been experimentally demonstrated.     

Generation of Primary Input Blocking Pattern for Power Minimization during Scan Testing

In this paper we propose a new approach to generate a primary input blocking pattern for applying to the primary inputs during shift cycle such that the switching activity occurred in the combinational part of the circuit under test can be suppressed as much as possible. The primary input blocking technique suppresses transitions of gates in the combinational part during scan by assigning controlling values to one of the gates' inputs. However, simultaneously assigning controlling values to the gates may result in conflicts in the setting of binary values on the primary inputs. Instead of the heuristics based on fanout in other approaches, we use the impact function which is based on transition density to determine the priorities of the gates to be blocked. Experiments performed on the ISCAS 89 benchmark circuits show that the proposed approach can always produce better results than the existing approaches.