With the development of various radio communication systems in recent years, spectrum sharing in heterogeneous networks has received a considerable amount of research attention for the efficient use of spectral resources, as the lack of these has emerged as an important problem. Prevalent spectral sharing methods focus on improving total throughput, and ignore lower throughput along the cell edges. Hence, users receive unfair throughput that is dependent on their place. To solve this problem, in this paper, we propose improving fairness in spectrum sharing by considering Coordinated Multi-Point transmission /reception (CoMP). In order to promote cell edge performance in particular, we propose a method to allocate parts of spectral resources to cell edges to use CoMP and wireless systems therein using spectrum sharing. We used simulations to confirm that the proposed method improves cell edge performance and fairness in terms of user throughput.