Physically secure digital signal processing for blind differentially-spread wireless M2M networks

• US 10,154,397 B2
• Filed: 08/24/2016
• Issued: 12/11/2018
• Est. Priority Date: 01/05/2013
• Status: Active Grant

• Current Assignee: Brian G. Agee
• Original Assignee: Brian G. Agee
• Inventors: Agee, Brian G.
• Primary Examiner(s): Tayong, Helene
• Application Number:
  US15/246,121
• Publication Number:
  US 20160365892A1
• Time in Patent Office: 839 Days
• Field of Search: 375133, 375144
• CPC Class Codes: H04B 1/692 Hybrid techniques using combinations of two or more spread spectrum techniques
• CPC Class Codes: H04B 1/7103 the interference being multiple access interference
• CPC Class Codes: H04B 1/7156 Arrangements for sequence synchronisation
• CPC Class Codes: H04B 2001/7154 with means for preventing interference
• CPC Class Codes: H04J 13/0007 Code type
• CPC Class Codes: H04W 4/70 Services for machine-to-machine communication [M2M] or machine type communication [MTC]

Abstract

A method and apparatus for physically secure communication over machine-to-machine (M2M) networks is claimed, through the use of frequency-hop and random access spread spectrum modulation formats employing using truly random spreading codes and time/frequency hopping and receiver selection strategies at the transmitters in the M2M network, blind signal detection and linear signal separation techniques at the receivers in the M2M network, completely eliminating the ability for an adversary to predict and override M2M transmissions. Additional physical security protocols are also introduced that allow the network to easily detect and identify spoofing transmissions on uplinks and downlinks, and to automatically excise those transmissions as part of the despreading procedure, even if those transmissions are received at a much higher power level than the intended transmissions. Extensions to weakly and strongly macrodiverse networks are also described, which provide additional efficiency and security improvements by exploiting the route diversity of the network.

Claims

1. A method for physically secure digital signal processing for wireless machine-to-machine (‘

M2M)’

) networks, said networks comprising at least one set of transceivers comprising at least one Signaling Machine (‘

SM’

) and one Data Aggregation Point (‘

DAP’

) with each SM and DAP comprising at least one antenna and one transceiver for exchanging wireless transmissions, said method comprising;

generating transmission information that is;

randomly varied at every transmitter in the network; and

,

neither known to any receiver in, nor provisioned by, the network;

using that transmission information to directly spread a signal with any baseband modulation format, thereby implementing differentiation between transmitters in the network by any of a spreading code and baseband signal samples;

applying a timing advance to an intended uplink receiver;

then fitting each transmission into a series of frames of Upload Transmissions (‘

UpLink’

) and Download Transmissions (‘

DownLink’

);

transmitting from any of, the SM on an UpLink and the DAP on a Downlink; and

,

despreading, at an intended receiver for that transmission, the received signal.

2. The method as in claim 1 further comprising:

incorporating into each transmission at each transceiver a Frame-Synchronous (‘

FS’

) differentiator for that transmission; and

using time-channelized despreading at the intended uplink receiver for that transmission.

3. The method as in claim 2, wherein the step of using time-channelized despreading at the intended uplink receiver for that transmission further comprises:

using any of source spreading and receive spreading elements, baseband signal samples, and known and exploitable structure from the transmission information, to despread a demultiplexed uplink data sequence

4. The method as in claim 1 for physically secure digital signal processing for wireless M2M networks, further comprising implementing for each uplink transmission received at multiple receivers receiving a signal from the same transmitter, a weakly-macrodiverse uplink despreading method.

5. The method as in claim 4, wherein the step of implementing for each uplink transmission a weakly-macrodiverse uplink despreading method further comprises:

transmitting an uplink transmission from at least one user to a set of multiple receivers, at each member receiver detecting and substantively despreading that uplink transmission to a received signal;

uploading from each member receiver its respective detected and substantively despread received signal to a central site;

associating the uploaded received signals at that central site; and

,

demodulating the uploaded received signals into the source symbols using a multidimensional demodulation algorithm.

6. The method as in claim 1 for physically secure digital signal processing for wireless M2M networks, further comprising implementing for each uplink transmission received at multiple receivers receiving a signal from the same transmitter, a strongly-macrodiverse uplink despreading method.

7. The method as in claim 6 wherein the step of implementing for each uplink transmission a strongly-macrodiverse uplink despreading method further comprises:

transmitting an uplink transmission from at least one user to a set of multiple receivers;

detecting and generating from the received uplink transmission at each member receiver a

8. The method as in claim 7, wherein the step of demodulating the uploaded received signals into the source symbols further comprises:

stacking the associated DAP data matrices into an L_RM_smp×

M_sym network data matrix X_R(n_frame,k_dwell) given by

9. The method as in claim 1, wherein the step of generating transmission information that is randomly varied at every node in the network, and neither known to the receivers in the network nor provisioned by the network, further comprises generating transmission information that is both randomly varied amongst transmitters in the network and at every transmitter is randomly varied over frames and dwells.

10. The method as in claim 1, wherein the step of despreading, at the intended uplink receiver for that transmission, the received signal, further comprises:

detecting all sources intended for the receiver;

using those sources to estimate key parameters of those signals;

using those key parameters to develop linear combining weights that can substantively despread those signals;

using those linear combining weights to produce despread source symbols; and

demodulating those despread source symbols.

11. The method as in claim 1, wherein the step of despreading, at the intended receiver for that transmission, further comprises:

detecting signals of interest (SOI'"'"'s) to the intended receiver;

estimating key parameters of those signals in which the baseband data takes on a role of a Cyclic-Prefix Direct-Sequence (CPDS) temporal signature vector;

using the key parameters to develop a set of linear combiner weights that extract the SOI baseband symbol streams and without knowledge of the content excise any signals not of interest (SNOI'"'"'s) to the intended receiver;

computing a despread symbol matrix;

computing despread symbols using the linear combining weights; and

,

using demodulation and decryption to extract source information from the despread symbols.

12. The method as in claim 1, wherein the step of despreading, at the intended receiver for that transmission, further comprises:

detecting signals of interest (SOI'"'"'s) to the intended receiver;

estimating key parameters of those signals in particular their observed frequencies-of-arrival (FOA)