In an infrastructure-less wireless ad hoc or sensor network, communication may be achieved between mobile nodes without a central entity (base station) using a half-duplex Slotted ALOHA protocol. The probability of success and the throughput per mobile node can be reduced significantly, if the network is attacked by jamming signals. Mitigating the effect of jamming signals using multi-packet transmission (MPT) and/or multi-packet reception (MPR) capabilities of each mobile node is studied. The effect of the probability of success reduction due to jamming signals can be mitigated by using the MPT and the MPR capabilities of each mobile node. Similarly, reduced throughput can be increased using the same techniques. The maximum throughput per mobile node can be obtained by the proper adjustment of the transmitting probability of each mobile node and the receiving probability of each mobile node. A lower mitigation of the maximum throughput reduction can be obtained by using only the MPT, if the jamming signal rate is very low. On the other hand, only the MPR capability can provide a lower mitigation of the maximum throughput reduction. The effect of jamming signals on the maximum throughput can be mitigated successfully at all traffic load conditions, if the MPT and the MPR capabilities work together.