Systems and methods for providing adaptive pulse position modulated code division multiple access for ultra-wideband communication links

A transmitter for transmitting a pulse position modulated spread spectrum signal in a communications system, comprising:

• a spreading code sequence generator for generating at least one spreading code sequence, each spreading code sequence comprising a plurality of elements having either a first value or a second value;
• a spread spectrum encoder, operable for:
• receiving a stream of input data bits;
• receiving at least one spreading code sequence from the spreading code generator;
• and
• encoding each bit of the stream of input data bits into a symbol, having a finite symbol period, and comprising a plurality of chips, wherein each chip comprises a chip period;
• associating at least one code element with each chip in the symbol;
• and
• generating an encoded pulse in each chip of the symbol, wherein the encoded pulse has a value equal to the product of the bit and the code value associated with the particular chip;
• a pulse position modulator operable for modulating each pulse by shifting the position of the pulse within each chip based on the encoded value of the pulse;
• and
• an antenna for transmitting the pulse position modulated signal over an ultra-wideband communications channel.

A receiver for receiving a pulse position spread spectrum signal in an ultra-wideband (UWB) communications system, the pulse position modulated spread spectrum signal comprising a plurality of symbols, each symbol representing one data bit and consisting of a plurality of chips, each chip having a chip period and each chip containing an encoded pulse, comprising:

• an ultra-wideband antenna operable for receiving the pulse position modulated spread spectrum signal;
• a demodulator operable to demodulate the pulse position modulated spread spectrum signal by detecting the position of the encoded pulse within each chip period to determine a value associated with the encoded pulse;
• and
• a spread spectrum decoder operable for:
• receiving at least one spreading code sequence;
• and
• decoding each symbol by combining the appropriate code value of the spreading code sequence with the value of encoded pulse in each chip of the symbol to extract the data bit.

A method of receiving a pulse position modulated spread spectrum signal, the pulse position modulated spread spectrum signal comprising a plurality of symbols, each symbol representing one data bit and consisting of a plurality of chips, each chip having a chip period and each chip containing an encoded pulse, comprising:

• receiving the pulse position modulated spread spectrum signal;
• demodulating the pulse position modulated spread spectrum signal by detecting the position of the encoded pulse within each chip period to determine a value associated with the encoded pulse;
• and
• receiving at least one spreading code sequence;
• and
• decoding each symbol by combining the appropriate code value of the spreading code sequence with the value of encoded pulse in each chip of the symbol to extract the data bit.