FDMA和CDMA的区别

1. 频分多址(FDMA)：
FDMA 是信道化协议，其中带宽被划分为各种频段。每个站都分配有用于发送数据的频带，并且该频带始终为特定站保留，如下所示：

不同站点的频段之间被一小段未使用的频率带隔开，未使用的频段称为保护带，防止站点干扰。这就像数据链路层中的访问方法，其中每个站的数据链路层告诉其物理层将传递给它的数据制成带通信号。信号是在分配的频带中创建的，物理层没有物理复用器。

2. 码分多址(CDMA)：
在CDMA中，所有站点可以同时传输数据。它允许每个站点始终在整个频率上传输数据。多个同时传输由唯一的代码序列分隔。每个用户都分配有唯一的代码序列。

在上图中，有4个站点标记为1、2、3和4。数据分配给相应的站点为d ₁ 、d ₂ 、d3和d ₄以及分配给相应站点的代码为c ₁ 、c ₂ 、c ₃和 c ₄ 。

FDMA 与 CDMA 的区别：

Sr. No.	FDMA	CDMA
1.	FDMA stands for Frequency Division Multiple Access.	CDMA stands for Code Division Multiple Access.
2.	Sharing of bandwidth among different stations takes place.	There is sharing of both i.e. bandwidth and time among different stations takes place.
3.	There is no need of any codeword.	Codeword is necessary.
4.	There is only need of guard bands between adjacent channels are necessary.	In this, both guard bands and guard time are necessary.
5.	Variable transmission rate is difficult.	Variable transmission rate is easy..
6.	There is no Near-far problem.	There is existence of Near-far problem.
7.	In this, power efficiency can be reduced.	In this, full power efficiency is required.
8.	Capacity of system is low.	Capacity of system is large.
9.	It is costly.	In this, only installation is costly and operating cost is low.
10.	It is less flexible.	It is more flexible.