In this work, we are interested in the negotiation between several PU and several SU in a cognitive radio context by using multi-agent systems. So, we have implemented PU coalitions (CPU) and SU coalitions (CSU). We also used the multi-criteria decision (TOPSIS algorithm) to best meet the needs of SU.Management by coalitions and the aggregation technique that we have used in this context significantly reduce the number of messages exchanged in the network. Processing negotiations simultaneously by several CSU minimizes response time side SU.