Cooperative transmission schemes are used in wireless networks to improve the spectral efficiency. In a multi-cell environment, other cell interference (OCI) degrades the performance of wireless systems. In this paper, we study the performance of downlink sum rate for cell-edge users in a multi-cell environment under base station cooperation. The base-stations coordinate their transmission to the two cell-edge users in order to improve their Signal-to-interference-noise ratio (SINR) and throughput. Sum Capacity of cell-edge users for different transmit cooperation strategies is compared. Results show that Dirty Paper Coding (DPC) scheme, in a 2-cell cooperation, has significant gain in sum-rate compared to other cooperative schemes. However, when interference from all the other cells are considered, DPC performance is only marginally better than other low complexity cooperation schemes.