隠しコーナー: 5Gは地下鉄をどのようにカバーするのか?

地下鉄のトンネルの長さは通常1キロメートル以上です, 内部は狭くて窮屈です, そして曲がりもあります. 従来の指向性アンテナの使用, 信号の視角が小さい, ローカル信号の減衰が速い, そしてブロックされやすい. 5Gのために生まれた大型アンテナAAUも使いにくい.

上記の問題を解決するために, 線形信号カバレッジを形成するには、トンネルの方向に沿ってワイヤレス信号を均一に放出する必要があります。, 広域をカバーする3セクター地上マクロ局とは全く異なります。. これには特別なアンテナの使用が必要です: 漏れのあるケーブル.

The leaky cable is different. The outer conductor of the cable is not fully shielded. It has evenly distributed leakage slots or sparse weaves, which means that there are a series of small slots on it, so that the signal can be evenly passed from these slots. Leaked in.

In order to serve their respective users, the three major operators, チャイナモバイル, チャイナユニコム, と中国電信, must carry out subway line coverage. しかし, the tunnel space is limited, and it is really wasteful for each company to build a set of equipment. したがって, it is necessary to share the leaked cable and use a device to combine the signals of various frequency bands of different operators and then send them together. ケーブル.

This kind of equipment that can combine multiple signals of different operators, multiple frequency bands, and different uses is called a POI (Pont of Interface) combiner. This type of combiner has the advantages of multiple combined signals and low insertion loss, and is widely used in communication systems.

Beginning with 3G, MIMO has been on the stage of mobile communication and has become the most important means to increase system capacity; by 4G, 2x2MIMO has become a standard configuration, and 4x4MIMO is a high configuration; and in the 5G era, 4x4MIMO has become a standard configuration. All mainstream mobile phones can be supported.

したがって, support for 4x4MIMO must be considered for subway coverage. Since each channel of independent data sent by the MIMO system requires an independent antenna, 4 parallel leaky cables are required for tunnel coverage to realize 4×4 MIMO.

As shown in the figure below, 5G RRU is used as a signal source to output 4 signals, and then combine with other operators’ signal sources through a POI combiner, and then feed them into 4 parallel leaky cables to realize multi-channel transmission and reception. , This is the most direct and effective means to increase the system capacity.

この問題を解決するには, 複数のセルをスーパーセルに結合できます. 複数の線状セルの長さを組み合わせることで, それらは論理的に 1 つのセルに属します, これにより、単一セルのカバー範囲が数倍に拡張されます。, そして自然に過剰なものを避けます 切り替えと再選択, でも容量も減ります, 交通量があまり多くない場所での使用に非常に適しています。.