A new adaptive frequency hopping technique

This paper presents a new concept for adaptive frequency hopping wireless networks. In order to reduce the effect of the multiple access interference and increase the spectral efficiency. we propose to adapt the spacing between the hopping carriers according to the load and channel conditions. Indeed, for a given overall bandwidth and data bit-rate, reducing the separation between adjacent hopping channels has the positive effect of increasing the number of available hopping channels. This can definitely lead to decreasing the collision rate (i.e., reduces the probability of two signals interfering by hopping to the same channel at the same time). On the other hand, decreasing the space bet,between adjacent hopping frequencies make the system be more vulnerable to the transmissions in the adjacent channels. It is shown that the optimum carrier spacing depends. in addition to the type of the transmitter and receiver filters, on the number of users and the type of fading. Our numerical results reveals that an improvement of more than 30% in the overall spectral efficiency can be achieved by using the this concept.