MOBILE AD-HOC NETWORK

• US 20140247804A1
• Filed: 05/09/2014
• Published: 09/04/2014
• Est. Priority Date: 11/10/2011
• Status: Active Grant

• Current Assignee: Rafael Advanced Defense Systems Limited (Government of Israel)
• Original Assignee: Rafael Advanced Defense Systems Limited (Government of Israel)
• Inventors: Wermuth, Yoav, Wermuth, Michal, Avadis, Shimon, Fuchs, Itzhak, Weiss, Moshe
• Granted Patent: US 9,438,386 B2
• Time in Patent Office: Days
• US Class Current: 370/330
• CPC Class Codes: H04L 5/0005 Time-frequency
• CPC Class Codes: H04W 72/02 Selection of wireless resources by user or terminal
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

A mobile communication system which consists of a plurality of MANETs and nodes, which comprises a transceiver at each node. Each transceiver is a combination of a hopping transmitter operating according to a predetermined hopping sequence and rate and a wideband reference receiver, that can simultaneously receive at once, the whole operating band assigned to the system. Each transceiver further includes a circuitry for reallocating simultaneously receiving channels, dynamically spread over a wideband frequency range and circuitry for determining transmission hopping patterns to use the least possible number of frequencies according to the active population status of nodes that belong to the plurality of MANETs. This circuitry is also used for adapting the transmission scheme of the alien transceivers by finding time slots, in which a counterpart receiver at each remaining active node is not transmitting and a frequency channel, in which no other active node, neighboring the counterpart receiver transmits, while determining proper transmission frequency for each transmitting node.

Claims

1. A method for improving the spectral efficiency and scalability of a Mobile Ad-Hoc Networking (MANET) system, comprising:

a) at each node, providing a transceiver architecture that includes a combination of a transmitter being capable of dynamically selecting its channel frequencies within the whole operational RF band assigned to said system and a wideband receiver that is being capable of simultaneously receiving and processing signals received from nodes of said MANET in different frequency channels within the whole operational band assigned to said system, at once, and that includes channel frequencies, dynamically selected within a wide operating bandwidth;

b) allowing each node to simultaneously receive all other nodes which are in range within the whole operating band assigned to said system such that each of the remaining nodes determines the transmission frequency for each time slot;

for each transmitting node

c) finding time slots, in which a counterpart transceiver at each remaining active node is not transmitting and a frequency channel in which no other active node, neighboring said counterpart receiver, transmits; and

if no other node had chosen the same time slot, and if the transceiver is not transmitting in said slot, receiving the transmission, while allowing relay nodes to transmit simultaneously, using different channels,

wherein the decision which node in the MANET should transmit is made independently and separately for each time-slot.

2. A method according to claim 1, further comprising:

a) continuously collecting data regarding the number of active nodes that belong to the MANET system and regarding the presence of alien transceivers in the neighborhood of the active nodes;

b) processing the collected data;

c) determining frequency transmission patterns to use the least possible number of frequencies according to the active population status, transmission requirements and priorities of said nodes; and

d) using the processed data for adapting the transmission scheme in presence of alien transceivers, thereby avoiding transmission at frequencies of alien transmitters.

3. A mobile communication system consisting of a plurality of MANETs, comprising, at each node:

a) a transceiver being a combination of;

a.1) a hopping transmitter operating according to a predetermined hopping sequence and rate;

a.2) a wideband reference receiver, that is being capable of simultaneously receiving at once, the whole operating band assigned to said system;

b) circuitry for reallocating simultaneously receiving channels, dynamically spread over a wideband frequency range; and

c) circuitry for determining transmission hopping patterns to use the least possible number of frequencies according to the active population status of nodes that belong to said plurality of MANETs and for adapting the transmission scheme of said alien transceivers by finding time slots, in which a counterpart receiver at each remaining active node is not transmitting and a frequency channel in which no other active node, neighboring said counterpart receiver transmits, and determining proper transmission frequency for each transmitting node,

wherein the decision which node in a MANET should transmit is made independently and separately for each time-slot.

4. A mobile communication system according to claim 3, in which broadcast packets are received and transmitted.

5. A mobile communication system according to claim 3, in which the number of active channels is dynamically determined according to the number of active nodes and their data throughput demands.

6. A mobile communication system according to claim 3, in which the wideband reference receiver receives a plurality of channels within the whole operational RF band simultaneously, and includes:

a) a global band preselector for selecting a wide-band range;

b) a global Low Noise Amplifier for amplifying the selected wide-band range;

c) a global gain control unit, for controlling the global gain of said wideband reference receiver;

d) an anti-aliasing filter for filtering the amplified signals;

e) one or more Analog to Digital Converters (ADCs) for sampling the received signal;

f) an ADC driver for controlling the operation of said ADCs;

g) a control unit for controlling the gain of said global gain control unit; and

h) a digital signal processing unit for processing at once, samples from the whole RF band, wherein said digital signal processing unit is capable of;

h.1) simultaneously detecting a plurality of signals, transmitted by nodes of said MANET, each at a frequency channel within the assigned RF wide band;

h.2) simultaneously reconstructing the data carried by said plurality of signals.

7. A mobile communication system according to claim 3, in which the reference transmitter includes:

a) signal processing unit for generating a transmit baseband signal samples of the modulated signal, right at final frequency, in a digital form;

b) a Digital to Analog Converter (DAC) for converting said samples to analog values;

c) a first global-band filter for transforming said signal samples out of said DAC to an analog form;

d) a low-level RF pre-amplifier for pre-amplifying the analog signal being output by said global-band reconstruction filter;

e) a power-control attenuator, whose attenuation level is dynamically controlled by the control unit, for adjusting the power level of the amplified signal;

f) a second global-band filter connected to the attenuator output, for filtering far-out distortion products generated by said RF pre-amplifier;

g) an RF Driver followed by a final Power Amplifier (PA), for amplifying the output of said second global-band filter up to a level being sufficient to drive said final Power Amplifier (PA) to the maximal allowed transmit power;

h) a global-band Harmonic Filter, connected to the output of said final Power Amplifier (PA), for filtering the PA products at multiples of the transmit frequency; and

i) a transmit antenna for transmitting the filtered signal at the output of said global-band Harmonic Filter.

8. A mobile communication system according to claim 3, in which nodes receive and transmit by using half-duplex transceivers.

9. A mobile communication system according to claim 3, in which packets having different size are received and transmitted.

10. A mobile communication system according to claim 3, in which the digital signal processing section is implemented using Field Programmable Gate Arrays (FPGAs).

11. A mobile communication system according to claim 6, in which the received signal is directly sampled at Radio Frequency.

12. A mobile communication system according to claim 6, in which the received signal is indirectly sampled after down-conversion.