中文摘要：

The sum-rate capacity of CDMA and TDMA in vector broadcast channel is researched. An upper bound of sum-rate capacity in CDMA system and a lower bound of sum-rate capacity in TDMA system are derived respectively. According to these two bounds, the ratio of the two bounds at most can achieve min(M,K). Here M is the antenna number of the transmitter and K is the number of the user in this vector broadcast channel.