Research Article
Enhancing Radio Access Network Performance over LTE-A for Machine-to-Machine Communications under Massive Access
Table 2
RACH performance for 3GPP-compliant simulation and the proposed solutions.
| Evaluation metrics | ā | 3GPP compl. sim. | PRACH config. index | 3 picocells + PRACH config. index | 15 picocells + PRACH config. index | 3 agg. points (1:1) + PRACH config. index | 15 agg. points (1:1) + PRACH config. index | 3 agg. points (1:k) + PRACH config. index | 15 agg. points (1:k) + PRACH config. index |
| Access success probability (%) | 5k | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 10k | 99.86 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 16k | 82.78 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 20k | 58.90 | 100 | 100 | 100 | 100 | 100 | 100 | 100 | 25k | 38.21 | 99.91 | 99.95 | 100 | 99.92 | 99.91 | 99.91 | 99.92 | 30k | 26.86 | 97.44 | 98.53 | 99.94 | 97.39 | 97.41 | 97.51 | 97.69 |
| Average access delay (ms) | 5k | 28.61 | 25.70 | 25.49 | 25.2 | 25.55 | 25.49 | 25.36 | 25.73 | 10k | 40.41 | 26.71 | 26.44 | 25.87 | 26.62 | 26.61 | 26.77 | 26.56 | 16k | 67.05 | 28.11 | 27.85 | 26.79 | 27.9 | 28 | 27.85 | 27.89 | 20k | 71.62 | 30.01 | 29.29 | 27.61 | 30.18 | 30.07 | 29.9 | 29.91 | 25k | 71.71 | 36.05 | 34.36 | 29.41 | 35.75 | 35.92 | 36.05 | 35.64 | 30k | 71.26 | 47.86 | 44.39 | 33.47 | 47.76 | 47.68 | 47.55 | 47.27 |
| Average number of preamble transmissions | 5k | 1.58 | 1.48 | 1.46 | 1.45 | 1.47 | 1.47 | 1.46 | 1.48 | 10k | 2.16 | 1.53 | 1.51 | 1.48 | 1.52 | 1.52 | 1.53 | 1.52 | 16k | 3.46 | 1.60 | 1.59 | 1.53 | 1.59 | 1.6 | 1.59 | 1.58 | 20k | 3.68 | 1.70 | 1.67 | 1.58 | 1.71 | 1.71 | 1.7 | 1.69 | 25k | 3.68 | 2.02 | 1.93 | 1.67 | 2 | 2.01 | 2.02 | 1.98 | 30k | 3.66 | 2.64 | 2.46 | 1.89 | 2.64 | 2.63 | 2.62 | 2.59 |
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