Due to the increasingly scarce spectrum resources and densely deployed wireless networks, how to increase the spectrum utilization efficiency becomes a hot topic. Channel reservation and cooperative transmission have shown great potential to improve the spatial reuse and network capacity. However, it is difficult to avoid the shortcomings that simply adopting either scheme. In this paper, we propose the concept of reserved cooperative link and investigate the joint optimization of channel reservation and cooperative transmission to improve the network capacity. The concept of area capacity is introduced to characterize the spectral efficiency. After deriving its closed-form expression, the area capacity can be optimized by jointly selecting the optimal helper and employing the optimal reservation zone. Simulation results well validate our analysis, and show that the optimal reservation zone size is reduced by 30% compared with direct transmission with channel reservation. The corresponding optimal area capacity is significantly improved, and a gain of 140% can be obtained for the path loss exponent of 4.
['Yongping Zhang', 'Bo Li', 'Mao Yang', 'Zhongjiang Yan']
Capacity analysis of dense wireless networks with joint optimization of reservation and cooperation