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几种常用的无线接入技术1．模拟蜂窝它使用450MHz，800／900MHz频段，覆盖范围大，技术成熟，但抗干扰能力差，频率利用率低，容量小，保密性差。这类技术中，AMPS和TACS已在世界范围内广泛应用。它适用于城市、农村地区。在上海地区，1996年已使用一部分车载蜂窝电话解决了一
Several commonly used wireless access technologies 1. Analog cellular It uses 450MHz, 800 / 900MHz band, covering a large, mature technology, but anti-interference ability, low frequency utilization, small capacity, poor security. Among these technologies, AMPS and TACS have been widely used all over the world. It is suitable for urban and rural areas. In Shanghai, a portion of in-car cellular phones were used in 1996 to solve one