無線寬頻網(wǎng)絡(luò)設(shè)計規(guī)劃研究報告(完整版)
【正文】 he transmitter powers need be high, or high tower need be used so that each tower has a wider coverage area.Other factors, like channel assignment, antenna gains, orientation both in the vertical and horizontal directions, power control, all need be considered in a plete system design. Additionally, RSL contours are not circular because the ground is not flat and there are restrictions as to where a site can be have further plicate deployment of a real system. In this article, two WiFi RF systems are considered to illustrate some of the design aspects of a real cellular system.有關(guān)其它可能影響到R/ In this article, outdoor areas need be covered up to 90 % and indoor areas are ignored. Mainly, three nonoverlapping channels are used when cochannel interference is considered. Partially overlapping channels are also potential candidates when spatial separation proves appropriate. Adjacent channel interference is considered in this regard. %(WiFi).B． CoverageOne area of size 1600 m by 1200 m in Taipei basin is used to illustrate the process of coverage calculations. This example is shown in Figure 1 below. The buildups are extracted from the GIS map and are shown in pink. Sixty AP’s, s1 – s60, are considered. They are indicated with red circles. A grid is used to facilitate all calculations. The grid has 20,000 divisions per arc degree. Consequently, the grid cell dimension is about 5 m by 5 m. There are 27,949 outdoor grid cells in this example. RSSI’s are calculated according to the following formula: 1200公尺的范圍.( ).(s1—s60 ). degree劃分了20,000個小格子.( cell ), (最低接收功率)的計算公式如下: RSSI = 20 dBm – path loss – 17 dB (1)The first term is the AP EIRP, 100 mw, in dBm. The second term is the path loss calculated by TIREM11. The last term is the environmental loss due to building, cluttering, etc. All antennas are omnidirectional. The vertical radiation pattern used for all sites is shown in Figure 2 below. The 3dB width is about 15 degrees. The design results are very sensitive to this pattern. In the real design work, one has to make sure that the correct patterns are used.第一個要件是AP的EIRP.(最大輸出功率)為100mw,. Figure 1 System with 60 AP’s and buildup areas. Figure 2 Vertical antenna pattern.First, signal level from each AP to each grid cell point is calculated. For each point, if the RSSI of at least one AP is higher than the threshold of 80 dBm, the point has coverage. This is the downlink coverage. The uplink has slightly better coverage than the downlink and is not considered here. Coverage of the whole area when all 60 AP’s are used is shown in Figure 3.首先計算downlink coverage, . Figure 3 Coverage of 60 AP’s is %, with 17dB building loss and RSSL of –80dBm.For the RSSI calculations, 17 dB loss is used for building and environmental cluttering. The EIRP of the AP’s is set at 100 mw. The height of all AP’s is m. The height of the mobile antenna is m (3 ft). The frequency is GHz. Because of the flatness of the terrain, contours e out circular. In general,
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