## 4 Performance and Simulation Results
### The Modified BA Protocol, MBA
#### 4.3.1 MBA Performance and the Impact of Capture Effect  
In this subsection, a simulation of 300 tags existed in the entire zone of Figure 3 (105 tags in reader interrogation zone) moving at any velocity for GBT, TBT, GQT1, and GQT2 protocols, and velocities of 1 m/frame (blocking velocity) and 3.5 m/frame (non-blocking velocity) for the MBA were conducted, with varying \(\alpha\) from 0 to 1. Since all of the simulated protocols deal with C.E, the results presented in Figure 6a show the full read rate of the tags that existed in reader zone, which is 105 (the number of the tags existed in the green region of the simulated area) regardless of what the C.E probability is, while the results in Figure 6b show that the highest number of collision cycles was taken by GBT and TBT protocols. This is because they are non-blocking protocols, and the process of separating collided tags is done by the tags themselves (not by reader prefixes and independent of the tag IDs), with probabilistic (random) separation of collided tags. In Figure 6c, the results indicate that GBT and TBT consume the lowest number of idle cycles, except for the interval from 0 to 0.25 of \(\alpha\) in which GQT1 and GQT2 with uniform distribution of tags IDs exceed them, since they do not use either the blocking technique (MBA) or expanding or repeating the success prefixes (GQT1 and GQT2 respectively). For GQT1 and GQT2, Figure 6b, the number of collision cycles is reduced when the distribution of tag IDs is uniform, since reducing the common prefixes of tag IDs for QT protocols yields reduces the number of collision cycles [9]. For instance, the number of collision cycles for two tags with IDs 1000 and 0000 (shortest common prefix, null prefix) is one, while the number of collision cycles for 0001 and 0000 tags (longest common prefix, 000) is four. Thus, when the uniform distribution is obtained in the entire simulation area (\(3.5\ \times\ 10\) m\({}^{2}\), in which \(3.5\ \times\ 3.5\) m\({}^{2}\) is reader interrogation zone) as shown in Figure 3, the tags in reader zone will have IDs with shorter common prefixes than those when using the non-uniform distribution in the entire simulation area. In addition, for both GQT1 and GQT2, the number of collision cycles is the same for uniform and non-uniform distribution when C.E probability (\(\alpha\)) is about 0.4 or more. Besides, for both distributions, GQT1 exceeds GQT2 in small number of collision cycles for \(\alpha\) probability from about 0.1 to about 0.9. Moreover, both GQT1 and GQT2 beat GBT and TBT at consuming a lower number of collision cycles. In adverse, for idle cycles shown in Figure 6c, GQT2 uniform or non-uniform distribution always beats GQT1 uniform or non-uniform distribution, respectively, in consuming fewer idle cycles at any value of \(\alpha\) (except \(\alpha=0\) for uniform distribution). This happens because GQT2 uses repetition of success prefixes instead of expanding prefixes that used in GQT1. GQT2 (the both distributions) also consumes fewer idle cycles than any distribution of GQT1, as \(\alpha\) probability increases more than 0.5, and the number of idle cycles is only equal to two cycles when \(\alpha\) is equal to one. For total cycles, Figure 6d, GQT2 equals GQT1 (for uniform distribution and \(\alpha\) from 0 to 0.4) and surpasses GQT1 (for uniform distributions or non-uniform distributions, for both protocols, with \(\alpha\) larger than 0.4), and any distribution of GQT2 exceeds both distributions of GQT1 for \(\alpha\) from 0.6 to 1 in a lower total number of cycles. In addition, both GBT and TBT consume a lower total number of cycles than GQT1 and GQT2 for both distributions for the period of \(\alpha\) between 0.5 and 1. Lastly, the MBA, surpasses all of the previous protocols at consuming fewer collision and total cycles for the period of \(\alpha\) from 0 to 0.7 and blocking velocity of 1 m/frame.