OFDM system and method employing OFDM symbols with known or information-containing prefixes
Systems and methods for transmitting and receiving OFDM symbols are provided which enable the otherwise wasted transmission time normally used as a prefix for each OFDM symbol to contain useful information. At the receiver, the received signal is processed to convert received OFDM symbols from a linear convolution with the channel to a cyclic convolution.
1. A method comprising:
transmitting a signal comprising a non-OFDM segment containing known and/or unknown highly reliable data and an OFDM data segment before and/or after the non-OFDM segment by transmitting a slot structure comprising in sequence within a single slot:
a first data segment;
a first non-OFDM segment containing known data and/or unknown highly reliable data;
at least one second data segment;
a second non-OFDM segment containing known data and/or unknown highly reliable data, wherein each of the first and second non-OFDM segments includes a pilot channel, a signaling channel, and a traffic channel;
a third data segment;
wherein each data segment is an OFDM data segment.
2. The method of claim 1 , wherein the at least one second data segment comprises two second data segments.
3. The method of claim 2 , wherein each slot is 2048 chips in duration, each of the data segments is 400 chips in duration, and each of the first and second non-OFDM segments is 224 chips in duration.
4. The method of claim 3 , wherein each non-OFDM segment comprises a 64 chip MAC segment, a 96 chip pilot segment and a 64 chip MAC segment in sequence.
5. The method of claim 1 , wherein each non-OFDM segment comprises a 64 chip MAC segment, a 96 chip pilot segment and a 64 chip MAC segment in sequence.
6. A transmitter comprising:
a first transmit antenna;
OFDM signal generating circuitry for generating OFDM symbols for transmission;
non-OFDM signal generating circuitry for generating non-OFDM segments;
wherein the OFDM signal generating circuitry and the non-OFDM signal generating circuitry transmit a signal comprising a non-OFDM segment containing known and/or unknown highly reliable data and an OFDM data segment before and/or after the non-OFDM segment by transmitting a slot structure comprising in sequence within a single slot:
a first data segment;
a first non-OFDM segment containing known data and/or unknown highly reliable data;
at least one second data segment;
a second non-OFDM segment containing known data and/or unknown highly reliable data, wherein each of the first and second non-OFDM segments includes a pilot channel, a signaling channel, and a traffic channel;
a third data segment;
wherein each data segment is an OFDM data segment.
7. The transmitter of claim 6 , wherein the at least one second data segment comprises two second data segments.
8. The transmitter of claim 7 , wherein each slot is 2048 chips in duration, each of the data segments is 400 chips in duration, and each of the first and second non-OFDM segments is 224 chips in duration.
9. The transmitter of claim 8 , wherein each non-OFDM segment comprises a 64 chip MAC segment, a 96 chip pilot segment and a 64 chip MAC segment in sequence.
10. The transmitter of claim 6 , wherein each non-OFDM segment comprises a 64 chip MAC segment, a 96 chip pilot segment and a 64 chip MAC segment in sequence.