This paper takes a closer look at different wireless technologies:WiFi,WiMAX,E3G and B3G,and compares their market potentials,potential applications and areas of competitive threat,co-existence,and potential convergen...This paper takes a closer look at different wireless technologies:WiFi,WiMAX,E3G and B3G,and compares their market potentials,potential applications and areas of competitive threat,co-existence,and potential convergence in future wireless communication markets, so as to provide some available information for the industry in China.Meanwhile,some characteristics of future mobile service are also demonstrated.Moreover,some valuable analysis and suggestions are also proposed for Chinese choice and development of different wireless technologies.展开更多
Nowadays, wireless systems require compact multi band antennas that can dynamically change some of its fundamental parameters such as frequency band, polarization and radiation pattern. The novelty of the proposed wor...Nowadays, wireless systems require compact multi band antennas that can dynamically change some of its fundamental parameters such as frequency band, polarization and radiation pattern. The novelty of the proposed work lies in using two conducting strips that are perpendicular to each other. The longer strip resonates at 2.4 GHz and the shorter strip resonates at 3.5 GHz. The length and width of the Ground plane is made equal to length of the main arm and length of the side arm respectively. The results are obtained by simulating the antenna structure using simulation tool Ansoft HFSS v15.0. The Simulated antenna Gains were 6.2364 dBi and 7.1758 dBi for frequencies of 2.4 GHz and 3.5 GHz respectively. The antenna dimensions are 50 × 25 × 1.6 mm3 on a 1.6 mm thick FR-4 substrate.展开更多
The next generation of the wireless networks will consist of several overlapping tiers. Provision of undisrupted communication to mobile users is a challenging task. Handover delay is one of the problematic issues tha...The next generation of the wireless networks will consist of several overlapping tiers. Provision of undisrupted communication to mobile users is a challenging task. Handover delay is one of the problematic issues that users are faced in the heterogeneous networks. However, in the case of both the WiMAX and the WiFi technologies which are located at the same base station (BS), the vertical handover (VHO) delay will be less as compared with the two conventional WiMAX/WiFi heterogeneous networks with two different wireless Internet service providers (WISP). Nevertheless, protocol conversion is still adding delay and jitter for data exchange between the needed two technologies. In this paper, in order to reduce the delay in the protocol conversion, a new industrial design for WiWi (WiMAX and WiFi) adaptation layer is proposed. The realization of the interworking between these two standards is discussed and evaluated. The results show that the proposed scheme-with the scenario under study- has better performance than other related works.展开更多
A Printed monopole antenna was designed and manufactured with the wideband performances in two frequency bands. The antenna is compatible with WiMAX and WiFi standards. After reviewing a couple of literatures, the ant...A Printed monopole antenna was designed and manufactured with the wideband performances in two frequency bands. The antenna is compatible with WiMAX and WiFi standards. After reviewing a couple of literatures, the antenna was designed, analyzed and proven for two central frequencies, 2.5 GHz and 5.6 GHz, with much improved bandwidths. Finally, the antenna was manufactured with the overall size of 4 cm × 4.4 cm on Rogers (RO4003) substrate. The antenna is made into three L-shaped radiators. A 50 Ω microstrip feed line connects the port to the two L-shaped radiators of different lengths, thus providing two frequency bands. An inverted L-shaped radiator is printed on the less radiation upped side, to tune the antenna for wide band performances. The raised problem was solved with the integral equation solver of the Ansoft high frequency simulator structure (HFSS-IE). Optimal results are presented in this article: the simulation results in comparison with measured results. This antenna prototype’s overall dimensions would be readjusted according to any industrial and manufacturing requests.展开更多
文摘This paper takes a closer look at different wireless technologies:WiFi,WiMAX,E3G and B3G,and compares their market potentials,potential applications and areas of competitive threat,co-existence,and potential convergence in future wireless communication markets, so as to provide some available information for the industry in China.Meanwhile,some characteristics of future mobile service are also demonstrated.Moreover,some valuable analysis and suggestions are also proposed for Chinese choice and development of different wireless technologies.
文摘Nowadays, wireless systems require compact multi band antennas that can dynamically change some of its fundamental parameters such as frequency band, polarization and radiation pattern. The novelty of the proposed work lies in using two conducting strips that are perpendicular to each other. The longer strip resonates at 2.4 GHz and the shorter strip resonates at 3.5 GHz. The length and width of the Ground plane is made equal to length of the main arm and length of the side arm respectively. The results are obtained by simulating the antenna structure using simulation tool Ansoft HFSS v15.0. The Simulated antenna Gains were 6.2364 dBi and 7.1758 dBi for frequencies of 2.4 GHz and 3.5 GHz respectively. The antenna dimensions are 50 × 25 × 1.6 mm3 on a 1.6 mm thick FR-4 substrate.
文摘The next generation of the wireless networks will consist of several overlapping tiers. Provision of undisrupted communication to mobile users is a challenging task. Handover delay is one of the problematic issues that users are faced in the heterogeneous networks. However, in the case of both the WiMAX and the WiFi technologies which are located at the same base station (BS), the vertical handover (VHO) delay will be less as compared with the two conventional WiMAX/WiFi heterogeneous networks with two different wireless Internet service providers (WISP). Nevertheless, protocol conversion is still adding delay and jitter for data exchange between the needed two technologies. In this paper, in order to reduce the delay in the protocol conversion, a new industrial design for WiWi (WiMAX and WiFi) adaptation layer is proposed. The realization of the interworking between these two standards is discussed and evaluated. The results show that the proposed scheme-with the scenario under study- has better performance than other related works.
文摘A Printed monopole antenna was designed and manufactured with the wideband performances in two frequency bands. The antenna is compatible with WiMAX and WiFi standards. After reviewing a couple of literatures, the antenna was designed, analyzed and proven for two central frequencies, 2.5 GHz and 5.6 GHz, with much improved bandwidths. Finally, the antenna was manufactured with the overall size of 4 cm × 4.4 cm on Rogers (RO4003) substrate. The antenna is made into three L-shaped radiators. A 50 Ω microstrip feed line connects the port to the two L-shaped radiators of different lengths, thus providing two frequency bands. An inverted L-shaped radiator is printed on the less radiation upped side, to tune the antenna for wide band performances. The raised problem was solved with the integral equation solver of the Ansoft high frequency simulator structure (HFSS-IE). Optimal results are presented in this article: the simulation results in comparison with measured results. This antenna prototype’s overall dimensions would be readjusted according to any industrial and manufacturing requests.
