。在峰窝系统中，信道分配通常都是成对进行的，因此对每个正在通信 的移动用户，都有两个信道：一个是从用户端到基站端传输数据，称 为上行链路(Uplink),或反向链路(reverse link);一个是从基站端 到用户端传输数据，称为下行链路（Downlink),或称为前向链路 (forward link). For an uplink/downlink pair,uplink channels typically operate on a lower frequency than the downlink channel in an effort to preserve energy at the mobile nodes.This is because higher frequencies suffer greater attenuation than lower frequencies and consequently demand increased transmission power to compensate for the loss.By using low frequency channels for the uplink,mobile nodes can operate at lower power levels and thus preserve energy.9  在蜂窝系统中，信道分配通常都是成对进行的，因此对每个正在通信 的移动用户，都有两个信道：一个是从用户端到基站端传输数据，称 为上行链路（Uplink），或反向链路(reverse link) ；一个是从基站端 到用户端传输数据，称为下行链路（Downlink），或称为前向链路 (forward link) 。  For an uplink/downlink pair, uplink channels typically operate on a lower frequency than the downlink channel in an effort to preserve energy at the mobile nodes. This is because higher frequencies suffer greater attenuation than lower frequencies and consequently demand increased transmission power to compensate for the loss. By using low frequency channels for the uplink, mobile nodes can operate at lower power levels and thus preserve energy