Can Wi-Fi be used for wireless voice return?

As operators are facing almost crazy demands for mobile data, data congestion may occur in at least four different fields, including:

· Wireless Access Network;

· Network Signaling and Control;

· Grouping core networks;

· Return network.

Each type of bottleneck is a special challenge for operators. One of the following three methods can be used to solve the problem:

1.Increase the capacity of the affected network resources;

2.Distribute network resources to relieve congestion;

3. Take the above two methods at the same time.

It is widely believed that the transition to a smaller cellular network to expand the existing macro network is a potential "panacea", which can solve problems such as wireless access network congestion. But at the same time, this will lead to a new problem, that is, return. This has become one of the most intense topics in the telecom industry.

Mobile operators are planning to build their LTE Networks as a combination of the macro cellular network and the "bottom layer" network consisting of micro-cellular and micro-cellular networks. In order to meet the capacity density required by the rapidly growing mobile Internet bandwidth, the number of small cellular networks in some specific regions is much larger than the number of existing cellular networks. This also represents a new and very important back-to-back challenge because of the installation location of these small cell nodes (such as wire poles or other sub-district assets ), it is rarely suitable for optical fiber or microwave solutions.

The concept of LTE self-return or Mesh technology is a possible solution. However, given the early MeshWi-Fi network attempts to provide access and Mesh functions in the same band, the return traffic of this method quickly consumes the scarce accessible spectrum of LTE, and this method is very expensive. Using the 5GHz802. 11n point-to-point solution is an attractive alternative because it can easily provide the backhaul capability of the LTE cellular network that exceeds Mbps.

Become smaller

Small cellular networks are low-power, multi-RF access points (cellular/Wi-Fi/return), which expands the coverage of both indoor and outdoor areas, in order to increase network capacity and divert business traffic-during peak hours, up to 80% of business traffic can be diverted. Although small cellular networks are beneficial to the 3G services currently deployed, only the entire industry, especially the urban environment, is evolving towards a higher-capacity 4G/LTE network, the importance of small cellular networks will continue to rise. According to the latest report "FemtocellsandSmallCells: makingthemostofw.hertz" released by In-Stat, shipments of small cellular network devices will reach $2015 In 14 billion.

The problem is that as network operators continue to increase coverage and capacity, and expect to divert data to relieve traffic pressure, they also increase the pressure on their own cellular sites to return connections. In this world of small cellular networks, traditional point-to-point microwave, copper, and optical fiber backhaul solutions will quickly become no longer feasible or costly.

Although the cost of Point-to-Point Microwave Equipment has been reduced in recent years, it generally still requires line-of-sight transmission between the return center and many small cellular sites. The sub-6GHz NLOS solution adopts a point-to-multiple-point architecture, which is more suitable for intensive underlying networks. However, when the spectrum needs to be licensed, the narrowband channel will strictly limit the return capacity, and most sub-6GHz frequencies are very expensive and often do not have spectrum permits.

Another option is optical fiber, which is obviously the preferred solution for mobile operators (if feasible ). However, it is impractical to pull optical fiber cables to each small cell site because this method is too expensive, scattered, and time-consuming. Therefore, in the context of the current transition to a smaller cellular network, we must reconsider the traditional solution of cellular backhaul.

Requirement: New return Solution

To meet the deployment feasibility of small cell base stations, the new return solution needs to be very suitable for intensive urban environments and connected near-earth devices (including line-of-sight and non-line-of-sight transmission ).

Unlike most solutions, the free wireless band smart Wi-Fi network has become an effective and economical solution, this solution can solve the problem of authorization of small-size cellular network traffic in the wireless band, and plays a crucial role. Yes, it is to return the cellular network traffic! The specific reasons are as follows.

Assume that a mobile operator deploys and deploys a small cellular wireless network to increase the access capacity of areas with high user density of mobile data. These locations may be in the city center, for example, Beijing, Shanghai, or Hong Kong.

At present, this small cellular network is generally composed of Low-Power 3G and/or Wi-Fi nodes, or may also be composed of lte rf nodes in the future. However, no matter which type of access RF technology is used, how does the operator receive the data sent back from the access RF node to the network?

An obvious high-performance solution is optical fiber, which is feasible for the moment. Operators may need to lease optical fiber cables from fixed network operators, which will increase operation costs. But more importantly, mobile operators may need to place small-sized cellular networks without Optical Fiber POP.

The reality is that only small-sized cellular networks can be placed very close to users who need network access to increase network capacity. Therefore, the selection of small-sized cellular network site becomes the deciding factor for the effectiveness of small-sized cellular network deployment.

However, this will bring about a very practical problem, that is, the operator's website location for small-sized cellular networks is limited. Because it is impossible for all sites to have optical fiber POP. At the same time, configuring new optical fiber cables for each small honeycomb network site will also cause cost improvement and time delay. In this case, another alternative is obviously necessary.

Microwave wireless links are naturally an alternative technology that is well understood and can at least be used to partially solve this problem. However, although the microwave point-to-point (PtP) link has a high performance and reliable data and voice traffic backhaul carrying capacity, it still has some problems.

The first and foremost problem is that point-to-point microwave solutions usually rely on authorized frequency bands for transmission, which can improve reliability. However, on the other hand, the purchase of new authorized spectrum requires a lot of financial strength. At the same time, the RF capacity is directly related to how many frequencies are used for wireless transmission. This means that deploying more capacities on wireless access terminals will not only increase costs, it will also increase the shortage of the spectrum of the backhaul wireless network. In addition, point-to-point wireless links require highly skilled installation skills to align with or align wireless node devices at both ends. This will soon become a tough issue when crowded city areas or close to the ground.

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