A Fast Relay Selection Algorithm Over60GHz MM-Wave Systems

60GHz technology attracts widely attention recent years due to the huge unlicensed bandwidth and the ability to provide Gbps data transmission rate. But the small wavelength makes the mm-wave signals hard to diffract and penetrate through obstacles such as furniture and walls, which results in communication outage of LOS links. To overcome communication outage caused by obstacles, relays are employed to guarantee communication quality. There are many literatures on relay selection metrics.The relay selection methods proposed by802.11ad group and traditional exhaustive relay selection (ERS) algorithm lay more emphasis on the quality of relay link channel, thus paying little attention to the influence of relay selection speed. So far, few literatures pay attention to fast relay selection in mm-wave network. In this paper, a fast relay selection algorithm (FRS) based on geographical location information is firstly proposed. By selecting preliminary sectors, the FRS narrows the candidate relay set. Then, channel state information is collected for every relay in candidate set. The relay in candidate set with the best channel state will be selected as the best relay. On this basis, the distribution of optimal relay within different sectors can be derived and the candidate relay set can be further narrowed by modifying the number of preliminary sectors, so the fast relay selection is completed.The study in this paper uses MATLAB to verify the theory above. The simulation results show that FRS proposed in this paper takes relay selection speed into account, thus improving searching efficiency at the expense of the minimal loss of channel capacity. And the superiority will keep stable when the active link number increases.