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In this study, the factors affecting the capacity of indoor powerline networks were investigated. In order to establish the factors, first, the frequency response at various loads was determined using Anatory et al model. Then the mathematical approximation was used to determine the PSD of noise in dBm/Hz. The mathematical approximation represented the noise of a typical indoor channel similar to that obtained by Liu et al for indoor channel. Since, because of the limitations on the transmitted power, the field strength is limited to 30 dB V/m. Therefore, the range of PSD was varied between 90 dBm/Hz to 30 dBm/Hz while the frequency variation was between 1–30 MHz. Finally, the capacity was estimated for each indoor powerline network at every load.
Comparison of estimated capacity for the considered networks showed that the capacity of indoor networks is affected by; the number of branches between transmitter and receiver location, load impedances and branch lengths. This is because a PSD of -85dBm, -60dBm, -40dBm and -50dBm was required to support the data rate of 100Mbps, 90Mbps, 70Mbps and 15Mbps for indoor 1, indoor 2, indoor 3 and indoor 4 respectively with 50 ohm terminations. At the same time a PSD of -85dBm, -60dBm, -40dBm and -50dBm was required to support the data rate of 350Mbps, 340Mbps, 340Mbps and 28Mbps for indoor 1, indoor 2, indoor 3 and indoor 4 respectively with 10kohm terminations. In addition to that low PSD values seem to provide high data rates when the loads are terminated at high impedance. This was proved by the fact that a PSD of -40dBm supported a data rate of 340Mbps when the impedance is high, while a PSD of 30dB supported a data rate of 1Mbps at low impedance. |
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