Transmission mode detection in a modulated communication system
First Claim
1. In a data communication system having means for receiving data from a data source and means for transmitting data on a data communication medium, a preamble generator for generating a preamble for transmission with said data, said preamble generator comprising:
- means for encoding data word synchronization information into said preamble;
means for encoding error detection information into said preamble, said means for encoding error detection information providing at least single bit error detection, said preamble with said data word synchronization information and said error detection information having a length of n binary digits; and
means for encoding transmission mode information into said preamble, said preamble with said data word synchronization information, said error detection information, and said transmission mode information having a length of n+1 binary digits.
1 Assignment
0 Petitions
Accused Products
Abstract
A power line communication (PLC) apparatus wherein transmission mode information is encoded into each data packet while maintaining immunity from single bit errors. In the present invention, a power line communication system includes a transmitter/receiver (i.e. transceiver) which is coupled to a power distribution network. Data is transmitted through the power line by the transceiver in packets. The transceiver includes a preamble generator which creates a preamble for each of the data packets and a preamble decoder that decodes the preamble of a data packet and determines word sync for the packet. The preamble generated by the preamble generator consists of a carrier detect interval, a carrier sync interval, a bit sync interval, and a word sync pattern. The transceiver may select either BPSK or QPSK transmission modes on a data packet by data packet basis by encoding information into the packet preamble. Transmission mode information is encoded into the preamble using one of two seven-bit cross compatible word sync patterns for each data packet. Thus, one word sync pattern is used to define a BPSK transmission while the other word sync pattern is used to define a QPSK transmission. The transmitter may send data packets using either BPSK or QPSK on a packet by packet basis by generating the appropriate word sync pattern for each packet. The receiver uses the word sync pattern to determine the receive mode for each packet.
278 Citations
20 Claims
-
1. In a data communication system having means for receiving data from a data source and means for transmitting data on a data communication medium, a preamble generator for generating a preamble for transmission with said data, said preamble generator comprising:
-
means for encoding data word synchronization information into said preamble; means for encoding error detection information into said preamble, said means for encoding error detection information providing at least single bit error detection, said preamble with said data word synchronization information and said error detection information having a length of n binary digits; and means for encoding transmission mode information into said preamble, said preamble with said data word synchronization information, said error detection information, and said transmission mode information having a length of n+1 binary digits. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. In a data communication system having means for receiving data from a data source and means for transmitting data on a data communication medium, a preamble decoder for interpreting preamble information received with said data, said preamble decoder comprising:
-
means for receiving a preamble, said preamble having encoded data word synchronization information, error detection information, and transmission mode information, said error detection information providing at least single bit error detection, said preamble with said data word synchronization information and said error detection information having a length of n binary digits, said preamble with said data word synchronization information, said error detection information, and said transmission mode information having a length of n+1 binary digits; means for decoding said transmission mode information; and means for switching to a receive mode specified by said transmission mode information decoded by said means for decoding. - View Dependent Claims (9, 10)
-
-
11. In a data communication system having means for receiving data from a data source and means for transmitting data on a data communication medium, a process for generating a preamble for transmission with said data, said process comprising the steps of:
-
encoding data word synchronization information into said preamble; encoding error detection information into said preamble, said step of encoding error detection information providing at least single bit error detection, said preamble with said data word synchronization information and said error detection information having a length of n binary digits; and encoding transmission mode information into said preamble, said preamble with said data word synchronization information, said error detection information, and said transmission mode information having a length of n+1 binary digits. - View Dependent Claims (12, 13, 14, 15, 16, 17)
-
-
18. In a data communication system having means for receiving data from a data source and means for transmitting data on a data communication medium, a process for interpreting preamble information received with said data, said process comprising the steps of:
-
receiving a preamble, said preamble having encoded data word synchronization information, error detection information, and transmission mode information, said error detection information providing at least single bit error detection, said preamble with said data word synchronization information and said error detection information having a length of n binary digits, said preamble with said data word synchronization information, said error detection information, and said transmission mode information having a length of n+1 binary digits; decoding said transmission mode information; and switching to a receive mode specified by said transmission mode information decoded in said decoding step. - View Dependent Claims (19, 20)
-
Specification