Ultra wide bandwidth spread-spectrum communications system

• US 20050259720A1
• Filed: 06/24/2005
• Published: 11/24/2005
• Est. Priority Date: 12/12/1997
• Status: Active Grant

• Current Assignee: North Star Innovations Inc. (Wi-LAN Inc.)
• Original Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Inventors: McCorkle, John W., Rofheart, Martin
• Granted Patent: US 7,408,973 B2
• Time in Patent Office: Days
• US Class Current: 375/130
• CPC Class Codes: H04B 1/71632 Signal aspects H04B1/7172 and H04B1/7176 take precedence
• CPC Class Codes: H04B 1/7172 Pulse shape in general H04L25/03834
• CPC Class Codes: H04B 1/7174 Pulse generation in general H04L25/03834
• CPC Class Codes: H04B 1/7176 Data mapping, e.g. modulation
• CPC Class Codes: H04B 1/7183 Synchronisation
• CPC Class Codes: H04B 1/719 Interference-related aspects
• CPC Class Codes: H04L 25/4902 Pulse width modulation; Pulse position modulation
• CPC Class Codes: H04L 27/0004 using wavelets

Abstract

An ultra wide bandwidth, high speed, spread spectrum communications system uses short wavelets of electromagnetic energy to transmit information through objects such as walls or earth. The communication system uses baseband codes formed from time shifted and inverted wavelets to encode data on a RF signal. Typical wavelet pulse durations are on the order of 100 to 1000 picoseconds with a bandwidth of approximately 8 GHz to 1 GHz, respectively. The combination of short duration wavelets and encoding techniques are used to spread the signal energy over an ultra wide frequency band such that the energy is not concentrated in any particular narrow band (e.g. VHF: 30-300 MHz or UHF: 300-1000 MHz) and is not detected by conventional narrow band receivers so it does not interfere with those communication systems. The use of pulse codes composed of time shifted and inverted wavelets gives the system according to the present invention has a spatial resolution on the order of 1 foot which is sufficient to minimize the negative effects of multipath interference and permit time domain rake processing.

Claims

1. A data communications method, comprising:

receiving a stream of digital data;

repetitively generating a codeword to produce a digital code signal;

modulating the codeword digital code signal in accord with the digital data, to generate a modulated code signal;

generating a modulated ultrawideband impulse signal in response to the modulated code signal, wherein;

(a) the modulated ultrawideband impulse signal comprises a sequence of short impulse wavelets, and

(b) the sequence of short impulse wavelets is modulated in accord with bits of the modulated code signal; and

outputting the modulated ultrawideband impulse signal.

2-44. -44. (canceled)

45. A data communications method, comprising:

receiving a stream of digital data that are mapped such that a first data value corresponds to a positive value and a second data value corresponds to a negative data value;

repetitively generating a codeword to produce a digital code signal;

modulating the codeword digital code signal by either the positive value or the negative value in accord with the digital data, to generate a modulated code signal;

generating a modulated ultrawideband impulse signal by modulating the modulated code signal with a pulse shape; and

outputting the modulated ultrawideband impulse signal.