The realization of an FH-SSMA (frequency-hopping spread-spectrum multiple-access) communication system useful for 16 mobile subscribers within an area of 5 miles diameter is considered. The subscriber's information is digitized with the help of a CVSD (continuously variable slope detector) codec at the rate of 16 kb/s which is sent through a 4/16 orthogonal encoder giving coded data of rate 64 kb/s. The subscriber's address is chosen by a 4-bit binary code which in turn selects the address signal to be generated. The data are BFSK (binary frequency-shift keying)-modulated in such a way that the data bit and the 4-bit address will together select the frequency of the synthesizer giving out the frequency-coded address signal with modulation. Using noncoherent FH-BFSK techniques at the receiver, FH code acquisition and tracking are obtained. The entire system for 16 mobile subscribers occupies 2.4 MHz bandwidth for two-way communication. The receiver performance is represented by a P/sub e/ (probability of error) of 10/sup -3/.
展开▼
机译：考虑了对直径为5英里的区域内的16个移动用户有用的FH-SSMA（跳频扩频多址）通信系统的实现。订户的信息借助于CVSD（连续可变斜率检测器）编解码器以16 kb / s的速率进行数字化，并通过4/16正交编码器发送，给出速率为64 kb / s的编码数据。用户的地址由4位二进制代码选择，该代码依次选择要生成的地址信号。数据经过BFSK（二进制频移键控）调制，以使数据位和4位地址一起选择合成器的频率，从而给出经过调制的频率编码的地址信号。在接收器处使用非相干FH-BFSK技术，可以获得FH码的获取和跟踪。面向16个移动用户的整个系统占用2.4 MHz的带宽进行双向通信。接收机性能由10 / sup -3 /的P / sub e /（错误概率）表示。
展开▼
