nd Discussions In this section, we evaluate the performance of the proposed resource management frame- work. We compare with two access control schemes: (i) NS prior association (NSA) and (ii) BS prior association (BSA) based on traditional maximum SINR scheme [12]. Owing to the introduction of NS, some necessary modifications should be done in NSA and BSA. In detail, for a specific UE, the NSA scheme first finds the NS that satisfies the QoS requirement of the UE, and then finds the BS covered by this NS with sufficient bandwidth. BSA scheme first finds the BS with the maximum SINR for the UE, and then finds the NS deployed in this BS with the QoS guarantee satisfied. In both NSA and BSA schemes, if such a pair of NS and BS is found, the UE is admissible and associated with the NS and BS. We consider a network that consists of a macro BS (MBS) located at the center of a circular area with a radius of 500 m and varying number of pico BSs (PBSs), femto BSs (FBSs), NSs, and UEs. The transmit power of MBS (PBS) and FBS is set to 46, 30, and 20 dBm, respec- tively. We use L(d) = 34 + 40 log(d) and L(d) = 37 + 30 log(d) to model the pass loss for the MBS, PBSs, and FBSs, respectively [13]. All the BSs share 20 MHz bandwidth. Each NS ran- domly covers 4 BSs, and provides different rate and delay performance. UEs are randomly distributed in this area with different rate and delay requirements. In the first experiment, we compare the number of admissible UEs of the four AC poli- cies QoS-AC, Num-AC, NSA and BSA. In this experiment, we fix the number of NSs and BSs as 20 and 21 (including one MBS) respectively. Figure 9.3 shows the number of admis- sible UEs for the four AC policies with different UE densities. From Figure 9.3, we can see that the number of admissible UEs of QoS-AC and Num-AC is always higher than that of the other two traditional policies that do not consider the characteristics of NS. Specifi- cally, when the number of UEs is 200, the admissible number of UEs for Num-AC, QoS-AC, BSA, and NSA is 173, 142