留学 论文代写：FEC技术应用
FEC是一种用于控制无线系统数据传输过程中存在的误差的技术。其基本思想是，发送方在纠错代码的帮助下，以冗余的方式对消息进行编码。HARQ是一种将ARQ技术与FEC技术相结合的技术。由于这种结合，这种ARQ既可以进行正向纠错过程，又可以进行误差检测(Jin & Xia, 2014)。在混合ARQ的情况下，使用FEC方法对可能与各种误差相关的期望子集进行校正。另一方面，ARQ方法用于计算回退到纠正那些可能不会因为冗余而被纠正的错误。这种冗余是在无线通信的初始传输中发送的。用于HARQ的基本技术是向后纠错，即接收设备必须发送请求才能重新发送信息。这种方法在传输过程中丢失或损坏了一部分数据，需要传输设备重新发送相同的信息的情况下更有用(Wang et al .， 2015)。
留学 论文代写：FEC技术应用
另一方面，FEC实现的主要技术是传输信息的设备将冗余信息发送到各种潜在错误的补偿中。HARQ技术的工作依赖于不同的协议和算法。为了确保HARQ能够有效地完成，需要一致地使用奇偶校验位，需要进行循环冗余检查。在此之后，接收设备将执行不同的检查，以确保消息中出现的所有信息都是可读的，并且确实有一定的意义。如果发现接收到的信息没有任何意义，或者由于任何原因无法读取，接收设备将发送请求重新发送数据(Liu et al .， 2004)。在FEC的情况下，在纠错对的基础上将消息长度增加一倍或三倍。在HARQ的情况下，对错误的检测只向消息添加了几个字节。因此，这是一个非常小的增长长度。与FEC相比，长度的增加较小(Zorzi, 1998)。
留学 论文代写：FEC技术应用
FEC is a technique which is used for the purpose of control of the errors which are there in the process of data transmissions in the wireless systems. The primary idea behind the same is the process in which the sender does the encoding of the message in a redundant manner with the help of an error correcting code. HARQ on the other hand is a technique which uses the combination of ARQ technique and FEC technique. Because of this combination, this kind of ARQ can perform both the forward error correction process and the detection of the errors (Jin & Xia, 2014). In case of Hybrid ARQ, the FEC method is used for the purpose of correction of the expected subsets which may be related to each and every kind of error. On the other hand, the ARQ method is used for the calculation of the fallback to the correction of those errors which may not be corrected just because of the redundancy. This redundancy is sent in the initial transmission in case of wireless communications.The basic technique which is used in case of HARQ is backward error correction in which the receiving device has to send the request in order to re send the information. This kind of method is much more useful in such conditions where a part of the data which has been transmitted has been lost or corrupted during the process of transmitting and it is required that the transmitting device need to resend the same information again (Wang et al, 2015).
留学 论文代写：FEC技术应用
On the other hand the primary technique which is implemented in case of FEC is that the device which is transmitting the information sends that redundant information to make-up for all kinds of potential errors.The working of HARQ technique is dependent on different kinds of protocols and algorithms. In order to ensure that the HARQ is done efficiently, there is a use of parity bits quite consistently, there are cyclic redundancy checks. After this, different checks will be performed by the receiving device in order to ensure that all the information which is present in the message is readable and it does make some sense. If it is found that the information which has been received does not make any sense or when it can’t be read because of any reason, the receiving device will then send a request for resending of data (Liu et al, 2004).In case of FEC, there is doubling or the tripling of the message length on the basis of error correction parities. In case of HARQ, the detection of the error only added the couple of bytes to the message. Thus, it is a very small increase in the length. The increase in the length is smaller in comparison to FEC (Zorzi, 1998).