Siyang Liu Feifei Wang Ranran Zhang Yachen Wang Yuanan Liu Full Diversity Spreading code for Downlink Space-Time-Frequency Spreading CDMA. 5048-5052 2008 ICC http://dx.doi.org/10.1109/ICC.2008.947 conf/icc/2008 db/conf/icc/icc2008.html#LiuWZWL08