## 6 Discussion and Conclusions  
We investigated the transfer property of the power packet for indoor power line channels. Two fundamental power line network configurations--branched and branch-less--were considered. We used two-wire VVF electric cable, which is generally adopted for home power lines in Japan. We assumed matched impedance among the cables, the internal resistance in the packet transmitter and destination load. In the branched configuration, no appliance connection is assumed at the ends of branches except  
Figure 11: Bit error rate for RC pulse. Figure 10: Bit error rate for rectangular pulse. the destination load. We investigated the BER and the ratio between the power at the source and at the load by numerical simulations for the two system configurations. This power packet system is intended to be implemented in a DC power delivery system. The power packet is formed by an on-off switch connected to the DC power sources. Currently, AC power distribution systems lose more than \(20\%\) power because of power conversion. Our investigation shows that more than \(80\%\) of the source power can be dispatched to the destination load at frequencies up to 1 MHz for both the branched and branch-less channels used in this study. In addition, \"coloring\" and routing can be obtained by using the power packet, enabling the balancing of the power quality between the source and the load. Initially, power distribution is considered inside a small unit such as a home or a building with an independent power line from the commercial power system. From the BER evaluation, it is possible to estimate the bit energy at the transmitter to obtain the desired BER. This estimation makes it possible to estimate the number of bits that can be used as the header and footer. In the power packet dispatching system, the mixer and router are set at the connection point of the source, load, and power line. Here, the mixer and router are assumed to be included in the source and load, respectively. In practice, the impedances of the mixer and router are not always matched with the other impedances such as the internal resistance of the source. The impedance mismatching causes the reflection of voltage or current, and changes the transfer function of the channel. Moreover, the switching generates noise in the channel. The effects of switching noise and impedance mismatching at the sources, loads, mixers, and routers on the power packet dispatching system will be considered as a future topic of this study. The concept of power packetization and its routing leads to the digitization of the power transfer itself. For this, a more effective digital modulation method will be needed. Depending on the number of the sources and loads, other channel access methods may be used, apart from TDMA. The flow of the power packet contains a wealth of information on people's private daily consumption habits. Thus, the power packet system requires highly secure structure. The security of the system is a further topic to be discussed in this research. To implement the system, high-voltage and high-frequency power switching device are essential to the power packet. In addition, the switching devices should be as energy efficient as possible. Simultaneously, experimental verification is also important. The generation of power packets has already been verified in experiments in laboratory and in residential houses [2,4]. The implementation of SiC power devices depends on the system ratings. It has the benefit of low power loss for high frequency applications. The power packets have the potential to achieve efficient power transfer to the objective load. It is considered that the power packet routing system can achieve the on-demand home energy networking requirements [11]. It is also possible to stop the power supply to idling loads and save wasted electricity because of the path selection and bi-directional characteristics attained by the power packet transmission.