5G关键技术的多址技术，scma，一种新型的非正交接入技术，本代码主要是利用因子图来实例讲解scma的仿真。
稀疏码多址接入，就是应5G需求设计产生的一种非正交多址技术。在发送端通过多维调制和稀疏扩频将编码比特映射成SCMA码字，接收端通过多用户检测完成译码。相比4G的OFDMA技术，它可以实现在同等资源数量条件下，同时服务更多用户，从而有效提升系统整体容量。
运用ZF SIC 可简单使用
SHOW FULL COLUMNS FROM `jrk_downrecords` [ RunTime:0.004791s ]
SELECT `a`.`aid`,`a`.`title`,`a`.`create_time`,`m`.`username` FROM `jrk_downrecords` `a` INNER JOIN `jrk_member` `m` ON `a`.`uid`=`m`.`id` WHERE `a`.`status` = 1 GROUP BY `a`.`aid` ORDER BY `a`.`create_time` DESC LIMIT 10 [ RunTime:0.096794s ]
SHOW FULL COLUMNS FROM `jrk_tagrecords` [ RunTime:0.015110s ]
SELECT * FROM `jrk_tagrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 20 [ RunTime:0.001275s ]
SHOW FULL COLUMNS FROM `jrk_member` [ RunTime:0.001025s ]
SELECT `id`,`username`,`userhead`,`usertime` FROM `jrk_member` WHERE `status` = 1 ORDER BY `usertime` DESC LIMIT 10 [ RunTime:0.004666s ]
SHOW FULL COLUMNS FROM `jrk_searchrecords` [ RunTime:0.002617s ]
SELECT * FROM `jrk_searchrecords` WHERE `status` = 1 ORDER BY `num` DESC LIMIT 5 [ RunTime:0.003950s ]
SELECT aid,title,count(aid) as c FROM `jrk_downrecords` GROUP BY `aid` ORDER BY `c` DESC LIMIT 10 [ RunTime:0.015584s ]
SHOW FULL COLUMNS FROM `jrk_articles` [ RunTime:0.001210s ]
UPDATE `jrk_articles` SET `hits` = 2 WHERE `id` = 22837 [ RunTime:0.021126s ]
