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Chapter 7. HomePNA > HomePNA 2.0 QAM

7.2. HomePNA 2.0 QAM

The establishment of the HomePNA 1.0 standard was a success story for a group of industry promoters and supporters. These efforts involved laboratory testing, field verification, and compromising. Right after the confirmation of the HomePNA 1.0, the HomePNA consortium started the standardization effort of HomePNA 2.0 for a higher transmission throughput. It was the goal that the 2.0 version should be backward-compatible with the 1.0 version. Many participating companies have contributed individually or jointly. The joint technology proposal from Epigram and Lucent was selected as the base for the HomePNA 2.0 specifications. Because of its successful proposal, Epigram was subsequently bought by Broadcom. Very few knew that Epigram partially bought the idea of a telephone wiring–based home network from Travetim. Travetim was a start-up founded by Pete Foley with funding from Benchmark capital. I was involved with the feasibility analysis of a high-throughput–CAP (Carrierless AM/PM)-based transmission system over the existing in-house wiring for Travetim. My early analysis showed that a telephone wiring–based home network transmission system had a channel capacity of about 100 Mbps and that a practical system can be implemented at 30 Mbps with the adaptive equalization technique.

Adaptive equalization technology is used to combat extensive reflections caused by many branches of in-house wiring. With the improved channel condition, HomePNA 2.0 can increase the symbol rate to 2 or 4 Mbaud, depending on a particular wiring environment within the similar frequency band of between 4 and 10 MHz. Each HomePNA 2.0 symbol is able to carry 2 to 8 bits with Quadrature Phase Shift Keying (QPSK), 8-phase Shift Keying (SK), or Quadrature Amplitude Modulation (QAM) modulation of 4 Mbaud. A Frequency Diverse QAM (FDQAM) method, where a zero is inserted between adjacent symbols, is used for 2 Mbaud. The transmission throughput of this combined higher symbol rate and higher number of bits per symbol is between 4 and 32 Mbps. A reliable transmission throughput of 10 Mbps has been observed in field tests most of the time. A HomePNA 2.0 transceiver is backward-compatible with that of HomePNA 1.0 with its build-in HomePNA 1.0 transceiver. A HomePNA 2.0 device can talk to a HomePNA 1.0 transceiver via the HomePNA 1.0 packets. HomePNA 2.0 devices can also talk to each other with a special HomePNA 2.0 packet, starting with HomePNA 1.0 synchronization symbols, such that HomePNA 1.0 transceivers can participate in the same network.


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