Three Guiding Opinions on determining the size of an enterprise's wireless cellular network (1)

In wireless network deployment, the core content is how to deploy a cell. The most important task is to determine the size of the wireless cell. If the size of the wireless cell is determined inappropriate, a series of problems may occur. Specifically, the following problems are basically caused by the inappropriate size settings of wireless cells.

First, signal interference occurs between cells. If wireless cellular networks with the same frequency overlap, they will not produce 1 + 1> 2 results. For example, in A, A and B overlap each other. It is reasonable to say that the signal of the two cellular duplicates is strong. But this is wrong. Because a wireless client can only connect to one wireless router at the same time. Therefore, even in overlapping areas, the unlimited client only communicates with a wireless router. However, sometimes the signal of this overlapping area is not as good as that of the edge area. This is mainly because A and B use the same channel. The infinite signals with the same channel interfere with each other. Therefore, the signal in this coverage area is equivalent to 1 + 1 <2. At this time, the network administrator needs to adjust the size of the cell or the channel of the cell to reduce or avoid mutual interference.

Figure 1

Second, there is a blind spot between cells. Sometimes, when the client moves from one location to another, it will find that there is no wireless signal in the middle location. As shown in B, although three wireless routers form a cellular aggregation, a blind zone occurs between the three cellular networks due to the improper cell size settings. When the wireless client moves to this blind zone, it will find no wireless network signal. In this case, the network administrator needs to move the location of the wireless router or adjust the size of the cell to avoid this situation.

It can be seen that improper setting of the wireless cell size will cause many problems for wireless network access. So how many wireless cells are most suitable? I am very unfortunate about the high speed. There is no fixed number to provide. This requires the network administrator to constantly explore in practical work. However, I can talk about some guiding opinions based on my work experience. This helps network engineers avoid detours when deploying wireless networks.

Guidance 1: Consider bandwidth requirements

Although a wireless router is a third-tier product, a wireless network is a shared medium. That is to say, wireless clients in the same cell share and compete for bandwidth. For this reason, if the number of associated clients is large, the bandwidth that each client can enjoy may be relatively small or even congested. If the number of clients that can be connected to a cell is small, the number of clients that can be connected will also decrease. Therefore, when designing the cell size, network engineers need to consider the expected bandwidth allocated to the client.

Currently, wireless routers or launch sites on the market use 802.11b and 802.11ag (802.11a) standards. The previous standard has a maximum throughput of 6.8 M while the latter standard has a maximum throughput of 32 M. For this network project, we need to predict the number of wireless clients that may be clustered under a cell. Then, the maximum throughput is divided by the number of wireless clients, which is the maximum bandwidth the client can expect. However, network engineers should also predict that wireless clients cannot reach the maximum bandwidth. On the one hand, encapsulation and bandwidth competition will consume a certain amount of bandwidth; on the other hand, the location in the cell is different, and the bandwidth they can get is also different. Generally, the maximum bandwidth can be obtained only at the center of the cell. Therefore, network engineers need to leave some room to predict the maximum bandwidth, so they cannot be full.

Therefore, network engineers can control the number of wireless clients by controlling the size of the cell. If the wireless client is concentrated, such as a meeting room or an open office. Users who use wireless clients are concentrated. At this time, you can adjust the frequency to reduce the number of unlimited clients in a single cell, so that users can enjoy a certain bandwidth. In some airports, coffee shops and other places, although the area is relatively large, there are not many wireless Internet users. Therefore, the coverage of a single cell can be appropriately expanded in these areas.