Extended range communications for ultra-wideband network nodes
A system is provided that can introduce data redundancy into wireless communications, and in particular ultra-wideband (UWB) wireless communications to increase the communication range when transmitting data that has low transmission rates. Multipath degradation, introduced by the extended communications range, can be mitigated by frequency hopping between the orthogonal frequency-division multiplexed symbols of the ultra-wideband waveform. Frequency hopping can place adjacent symbols in different frequency channels for filtering. Data redundancy can be expanded in the time domain and/or the frequency domain, resulting in extended range.
1. An apparatus, comprising:
a data generator configured to generate data including one or more repeated symbols corresponding to one or more redundant bits of data;
a spreading code generator configured to generate a spreading sequence for the data;
a signal generator configured to generate an ultra-wideband modulated signal of the data;
a direct sequence spread signal generator configured to generate a direct sequence spread signal by combining the spreading sequence and the data, the combining of the spreading sequence and the data randomizing the one or more repeated symbols included in the data;
a signal modulator configured to map the direct sequence spread signal to a plurality of subcarriers comprising the ultra-wideband modulated signal, the mapping placing the one or more repeated symbols across multiple subcarriers comprising the ultra-wideband modulated signal such that a same symbol is placed on at least a first subcarrier and a second subcarrier comprising the ultra-wideband modulated signal; and
a transmitter configured to transmit, to another apparatus, the data by at least sending, to the other apparatus, the ultra-wideband modulated signal having the one or more repeated symbols placed across the multiple subcarriers comprising the ultra-wideband modulated signal.
2. The apparatus of claim 1 , further comprising a data cipher configured to encrypt the data.
3. The apparatus of claim 1 , further comprising a chip cipher configured to encrypt the direct sequence spread signal.
4. The apparatus of claim 1 , wherein the spreading sequence is a time-based spreading sequence that spreads the data.
5. The apparatus of claim 4 , wherein the time-based spread data sequence comprises a sequence of chips, and wherein the direct sequence spread signal generator is configured to interleave the sequence of chips that are mapped into modulation symbols in the ultra-wideband modulated signal.
6. The apparatus of claim 1 , wherein the spreading code generator is configured to change a start location for the spreading sequence of each symbol in the data.
7. The apparatus of claim 1 , wherein the spreading code generator comprises:
a time-based spreading code generator for generating a time-based spreading sequence.
8. The apparatus of claim 1 , wherein the spreading code generator comprises:
a frequency-based spreading code generator for generating a frequency-based spreading sequence.
9. The apparatus of claim 1 , wherein the one or more repeated symbols are randomized by the direct sequence spread signal applying a random change to the same symbol that is placed on at least the first subcarrier and the second subcarrier.
10. The apparatus of claim 1 , wherein the same symbol is further placed at different times on the first subcarrier and/or the second subcarrier.
11. A method, comprising:
generating, by a first apparatus, data including one or more repeated symbols corresponding to one or more redundant bits of data;
generating, by the first apparatus, a spreading sequence for the data;
generating, by the first apparatus, an ultra-wideband modulated signal of the data;
generating, by the first apparatus, a direct sequence spread signal by at least combining the direct sequence spread signal and the data, the combining of the spreading sequence and the data randomizing the one or more repeated symbols included in the data;
mapping, by the first apparatus, the direct sequence spread signal to a plurality of subcarriers comprising the ultra-wideband modulated signal, the mapping placing the one or more repeated symbols across multiple subcarriers comprising the ultra-wideband modulated signal such that a same symbol is placed on at least a first subcarrier and a second subcarrier comprising the ultra-wideband modulated signal; and
transmitting, by the first apparatus and to a second apparatus, the data by at least sending, to the second apparatus, the ultra-wideband modulated signal having the one or more repeated symbols placed across the multiple subcarriers comprising the ultra-wideband modulated signal.
12. The method of claim 11 , further comprising:
encrypting, by the first apparatus, the data.
13. The method of claim 11 , further comprising:
encrypting, by the first apparatus, the direct sequence spread signal.
14. The method of claim 11 , wherein the spreading sequence comprises a time-based spreading sequence.
15. The method of claim 14 , wherein the time-based spreading sequence comprises a sequence of chips, wherein the ultra-wideband modulated signal comprises a plurality of modulation symbols, wherein the sequence of chips are mapped into the plurality of modulation symbols in the ultra-wideband signal, and wherein the sequence of chips mapped into the plurality of modulation symbols are interleaved.
16. The method of claim 11 , further comprising:
changing a start location for the spreading sequence for each symbol in the data.
17. The method of claim 11 , wherein the spreading sequence is a frequency-based spreading sequence.