Throughput maximization is one of the major challenges in cognitive radio (CR) network. In this thesis work, two scenarios of throughput maximization are analyzed, which are: consideration of primary user (PU) protection and consideration of packet collision. In case of PU protection, throughput can be maximized by selecting either appropriate number of secondary users (SUs), or appropriate sensing time or appropriate fusion rule at the fusion centre. In case of packet collision, optimum frame length is selected to maximize the throughput. Energy detection (ED) based cooperative spectrum sensing (CSS) is used as spectrum sensing method in all these techniques and time division combining (TDC) CSS is used as the appropriate fusion rule. To show the relationship of throughput with above parameters, a simulation is set up considering voice over internet protocol (VOIP) activity as PU activity. The simulation results verify that throughput can be enhanced by selecting proper sensing time, proper number of SUs, proper fusion rule and proper frame duration. For example: with decreasing the required detection threshold from 0.9 to 0.5, the throughput is increased by 19%. Also, decrease in reporting delay from 0.6 to 0 ms causes the increase in throughput by 20%. For a fixed reporting time, the throughput decreases by almost 18% with the increase of every 5 number of SUs. For every 20 ms increase in frame duration, the collision probability increases by 39% and throughput decreases accordingly. Using TDC-CSS, the throughput increases by about 31%.