Interference in time-division duplex communication

Abstract

A method for severing a wireless time division duplex communication link, the time division duplex communication link being between a first node and a second node transmitting during a time slot assigned to the first node, the second node transmitting during distinct time slots assigned to the second node, and the first node transmitting in each of a plurality of frequency bands during each of the time slots assigned to the first node. The method may include further dividing a time slot assigned to the first node into consecutive time intervals and disrupting communication between the first node and the second node by transmitting, using a transmitter, a respective interfering signal during at least some of the time intervals while maintaining a frequency difference between any pair of consecutive interfering signals below a frequency difference threshold, each of the interfering signals being transmitted in a frequency band selected from a group of frequency bands, the group of frequency bands including a plurality of frequency bands, and where for at least two of the time intervals the interfering signals are transmitted in different frequency bands, and where the frequency difference threshold does not exceed a portion of a frequency gap between (a) a lowest frequency band of the plurality of frequency bands and (b) a highest frequency band of the plurality of frequency bands.

Description

Technical Field

[0001] The present invention, in some embodiments thereof, relates to time division duplex communications, and more particularly, but not exclusively, to interference with time division duplex communications.

Background Art

[0002] In time division duplex (TDD) communications, transmissions by network nodes are divided into different time slots. In some cases, nodes use different transmission schemes. For example, one node transmits frequency hopping packets, while a second node transmits fixed frequency packets during their respective assigned time slots.

[0003] Time division duplexing is very advantageous when there is asymmetry in uplink and downlink data rates. As the amount of uplink data increases, more communication capacity can be dynamically allocated, and as the traffic load decreases, capacity can be reclaimed.

[0004] In some cases, wideband jamming signals are used to disrupt communication uplink and / or downlink communications. To interfere with the reception of transmissions from node A at node B, a wideband jamming signal is transmitted towards node B. The jamming signal may be a high bandwidth (BW) noise signal (e.g., white Gaussian noise) or any other wideband signal (e.g., real data or a chirp signal).

[0005] One disadvantage of broadband jamming solutions is the potential interference to other communication links within the area. Another disadvantage is power loss, as power is distributed across the entire bandwidth. In addition, jamming solutions can simply disconnect two nodes without using disconnection commands, and therefore by increasing the bit error rate (BER) or decreasing the packet detection rate at node A's reception by node B.

[0006] Another approach to this problem is to transmit pulsed jamming signals during the node A time slot at all known frequencies used by node A in parallel. The disadvantage of the aforementioned solution is power loss, as the power is distributed across the entire frequency range of node A. Also, as in the previous solution, this jamming technique does not include disconnection commands. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] International Publication No. 93 / 26124 [Patent Document 2] International Publication No. 93 / 22850 [Non-patent literature]

[0008] [Non-Patent Document 1] M. Karlsson et al., “Jamming a TDD Point-to-Point Link Using Reciprocity-Based MIMO”, IEEE Transactions on Information Forensics and Security, 12(12), pp. 2957-2970, 11 July 2017 [Non-Patent Document 2] K. Grover et al., “Jamming and Anti-jamming Techniques in Wireless Networks: A Survey”, International Journal of Ad Hoc and Ubiquitous Computing Volume 17 Issue 4, Pages 197-215, December 2014 [Non-Patent Document 3] K. Parlin, “Jamming of Spread Spectrum Communications Used in UAV Remote Control Systems”, TALLINN UNIVERSITY OF TECHNOLOGY School of Information Technologies, 2017 [Overview of the Initiative]

[0009] Embodiments of the present invention are intended to disconnect and / or interfere with inter-node communication in a TDD communication link by having at least one of the nodes (hereinafter referred to as Node A) transmit on different frequency bands during different time slots assigned to it (i.e., frequency hopping). Transmission by Node A is interfered with by transmitting a series of high-power, short disconnect signals during each time slot assigned to Node A. Each disconnect signal is transmitted during its respective time interval within Node A's time slot. Since the disconnect device transmits over only a single Node A frequency band at any given time interval, the transmitted power of the disconnect signals can be maximized in each frequency band during a portion of Node A's time slot. Optionally, the disconnect signals are modulated with a disconnect command that, when received by Node B, disconnects Node B from Node A. Optionally, the disconnect signals may be predefined patterns and / or noise signals intended to interfere with communication between Node A and Node B. The disconnect command is an example of an interference signal.

[0010] In some embodiments, the disconnection signal is transmitted across multiple frequency bands during a given time interval. In this embodiment, the transmit power is divided among the multiple frequency bands, but the transmit power is still higher than when the disconnection signal covers the entire node A frequency range.

[0011] According to a first aspect of several embodiments of the present invention, a method is provided for disconnecting a wireless time-division duplex communication link between a first node transmitting during a time slot assigned to the first node and a second node transmitting during a separate time slot assigned to the second node. The first node transmits in different frequency bands during its time slots. The method includes: The time slot assigned to the first node is further divided into continuous time intervals, Send a disconnection signal during each of those time intervals. Each disconnection signal is transmitted in the frequency band used by the first node. The disconnection signals are transmitted in different frequency bands during at least two of their time intervals.

[0012] According to a second aspect of several embodiments of the present invention, an apparatus is provided for disconnecting a wireless time-division duplex communication link between a first node transmitting during a time slot assigned to the first node and a second node transmitting during a separate time slot assigned to the second node. The first node transmits in different frequency bands during its time slots. The apparatus includes a signal generator and a wireless transmitter. The signal generator further divides the time slot assigned to the first node into continuous time intervals and generates disconnect signals for each of the multiple time intervals. Each disconnect signal occupies each of the frequency bands. The disconnect signals are in at least two different frequency bands of those time intervals. The wireless transmitter transmits the disconnect signals for each time interval.

[0013] According to some implementations of the first or second aspect of the present invention, the disconnection signal is data-modulated for at least one of those time intervals.

[0014] According to some implementations of the first or second aspect of the present invention, for at least one of those time intervals, the disconnection signal is modulated by the disconnection command of the second node.

[0015] According to some implementations of the first or second aspect of the present invention, for at least one of those time intervals, the disconnection signal is modulated with a pseudo-random data sequence.

[0016] According to some implementations of the first or second aspects of the present invention, for at least one of those time intervals, the disconnection signal is one of the following: a predefined jamming signal and a random noise signal.

[0017] According to some implementations of the first or second aspect of the present invention, a transmission by a second node is monitored, and an approaching time slot for the first node is predicted based on the monitored transmission.

[0018] According to some implementations of the first or second aspect of the present invention, the transmission of a disconnection signal is initiated when the cessation of transmission by the second node is detected.

[0019] A transmission by the second node is analyzed to identify a disconnection in communication between the first and second nodes, and when a disconnection is identified, direct communication is attempted with the second node. Alternative responses from the first and second nodes to the interruption may include switching to a different group of frequencies on which communication can be resumed. Identification may also be achieved by cessating transmission in the pattern used or by analyzing data received from the second node.

[0020] For example, the remote controller will switch to another group of frequencies (when instructed by the UAV to do so because the UAV cannot receive its transmission), while the UAV will continue to transmit on the same frequency it used before the interruption starts. In this case, the system may detect from the data transmitted in the UAV's packets that the remote controller has been instructed to switch to another group of frequencies.

[0021] When such a switch occurs, similar changes are made in the transmission of the disconnection signal so that a new set of frequency bands is used.

[0022] According to some implementations of the first aspect or the second aspect of the present invention, transmissions by the second node are analyzed to identify a disconnection of communication between the first node and the second node, and when the disconnection is identified, direct communication is established with the second node.

[0023] According to some implementations of the first aspect or the second aspect of the present invention, each frequency band is selected from a specified list of frequency bands.

[0024] According to some implementations of the first aspect or the second aspect of the present invention, the disconnection signal is transmitted over the entire frequency range used by the first node during a single time slot.

[0025] According to some implementations of the first or second aspect of the present invention, a first node transmits in a known sequence of frequency bands, and disconnection signals are transmitted in a known sequence. The phase of the transmitted disconnection signals is altered by transmitting one of the disconnection signals in a frequency band that is not in a known sequence and continuing to transmit subsequent disconnection signals in a known sequence. This phase alteration may be performed multiple times, interfering with the transmission. Such phase alterations may be necessary when the system identifies that the connection between nodes has not been interrupted and may occur because the phase used is incorrect. The system may alter the phase several times until a disconnection occurs.

[0026] According to some implementations of the first or second aspects of the present invention, the entire frequency range used by the first node is interfered with by a disconnection signal during a single time slot of the first node.

[0027] According to some implementations of the first or second aspects of the present invention, each frequency band of the disconnection signal is selected as a continuous frequency band over the frequency range used by the first node.

[0028] According to some implementations of the first or second aspect of the present invention, at least two disconnect signals are transmitted in parallel in each of the frequency bands of at least one of their time intervals. The number of disconnect signals transmitted in parallel is less than the total number of frequency bands.

[0029] According to some implementations of the first or second aspect of the present invention, a first subset of frequency bands is transmitted during the time slot of a first node, and a second subset of frequency bands is transmitted during the subsequent time slot of the first node.

[0030] According to a third aspect of several embodiments of the present invention, a method is provided for controlling a device interfering with wireless time-division duplex communication. The time-division duplex communication is between a first node transmitting during time slots assigned to the first node and a second node transmitting during separate time slots assigned to the second node. The first node transmits in different frequency bands during its time slots. The method includes: Receiving wireless transmissions from the second node using a receiver, Determining a time slot assigned to the first node based on the received transmission, and further dividing the determined time slot into continuous time intervals, The device is instructed to transmit disconnection signals at multiple time intervals, each disconnection signal for transmission in each of multiple frequency bands, and for at least two of those time intervals, the disconnection signals are transmitted in different frequency bands.

[0031] According to a fourth aspect of several embodiments of the present invention, a controller for a wireless disconnection device for interfering with a wireless time-division duplex communication link is provided. The time-division duplex communication is between a first node transmitting during time slots assigned to the first node and a second node transmitting during separate time slots assigned to the second node. The first node transmits in different frequency bands during its time slots. The device includes: A receiver that receives wireless transmissions from a second node, To determine the time slot assigned to the first node based on the received transmission, Further dividing the time slot into continuous time intervals, and Instructing the disconnecting device to transmit disconnecting signals between multiple time intervals, each disconnecting signal for transmission in each of multiple frequency bands, and for at least two of those time intervals, the disconnecting signals are transmitted in different frequency bands. A signal analyzer that performs this function.

[0032] According to some implementations of a third or fourth aspect of the present invention, at least one signal parameter for generating a disconnection signal is provided to the device. According to some further implementations of a third or fourth aspect of the present invention, the signal parameter includes: The type of disconnection signal to send, Data for modulating the disconnection signal, Duration of time slot, The duration of each time interval, Each frequency band of the disconnection signal, The transmission power of each disconnection signal, and The number of disconnection signals transmitted in parallel.

[0033] According to some implementations of a third or fourth aspect of the present invention, the device is instructed to transmit a disconnection command for disconnecting a second node from a first node in at least one of the disconnection signals.

[0034] According to some implementations of the third or fourth aspect of the present invention, a disconnection in communication between the first node and the second node is detected from a received transmission, and the device is instructed to establish direct communication with the second node.

[0035] Unless otherwise defined, all technical and / or scientific terms used herein have the same meaning as generally understood by those skilled in the art to which the present invention relates. Similar or equivalent methods and materials described herein may be used in the practice or examination of the embodiments of the present invention, although exemplary methods and / or materials are set forth below. In case of any inconsistency, the patent specification, including definitions, will prevail. In addition, materials, methods, and examples are illustrative and not necessarily intended to limit the scope.

[0036] Implementations of the methods and / or systems of the embodiments of the present invention may include performing or completing selected tasks manually, automatically, or in combination thereof. Furthermore, according to the actual instruments and equipment of the embodiments of the methods and / or systems of the present invention, several selected tasks may be implemented using an operating system, by hardware, by software, by firmware, or in combination thereof.

[0037] For example, hardware for performing selected tasks according to embodiments of the present invention may be implemented as a chip or circuit. As software, selected tasks according to embodiments of the present invention may be implemented as a set of software instructions executed by a computer using any suitable operating system. In one exemplary embodiment of the present invention, one or more tasks according to exemplary embodiments of the method and / or system described herein are performed by a data processor, for example, a computing platform for executing a set of instructions. Optionally, the data processor includes volatile memory for storing instructions and / or data, and / or non-volatile storage for storing instructions and / or data, for example, magnetic hard disks and / or removable media. Optionally, network connectivity is also provided. A display and / or user input device such as a keyboard or mouse is also provided, optionally.

[0038] Several embodiments of the present invention are described herein, merely as examples, with reference to the accompanying drawings. It is emphasized here, with particular reference to the drawings, that the details shown are provided, as examples, for the purpose of illustrating embodiments of the present invention. In this regard, the drawings and the understood descriptions will make it clear to those skilled in the art how embodiments of the present invention may be put into practice. [Brief explanation of the drawing]

[0039] [Figure 1] This provides an exemplary scenario for interfering with the TDD communication link between node A and node B. [Figure 2] This is a simplified flowchart of a method for disconnecting a wireless time-division duplex communication link according to an embodiment of the present invention. [Figure 3A] The following shows an integrated disconnection signal used to interfere with a TDD communication link according to each of the exemplary embodiments of the present invention. [Figure 3B] The following shows an integrated disconnection signal used to interfere with a TDD communication link according to each of the exemplary embodiments of the present invention. [Figure 4] The following shows an integrated disconnection signal used to interfere with a TDD communication link according to each of the exemplary embodiments of the present invention. [Figure 5] The following shows an integrated disconnection signal used to interfere with a TDD communication link according to each of the exemplary embodiments of the present invention. [Figure 6] This is a simplified block diagram of a cutting device for disconnecting a wireless time-division duplex communication link according to an embodiment of the present invention. [Figure 7A] This shows the timing scenarios for each TDD communication link. [Figure 7B] This shows the timing scenarios for each TDD communication link. [Figure 7C] This shows the timing scenarios for each TDD communication link. [Figure 8]This is a simplified flowchart of a method for controlling a cutting device according to an embodiment of the present invention. [Figure 9] This is a simplified block diagram of a controller for a wireless disconnection device according to an embodiment of the present invention. [Figure 10] This is a simplified block diagram of a cutting device according to one exemplary embodiment of the present invention. [Figure 11] This is one example of the method. [Figure 12] This is an example of a timing diagram. [Figure 13] This is an example of a timing diagram. [Figure 14] This is an example of a timing diagram. [Modes for carrying out the invention]

[0040] In some embodiments thereof, the present invention relates to time-division duplex communication, and more specifically, to interference with time-division duplex communication, but not exclusively.

[0041] TDD communication links are often used for wireless communication between a controller and an unmanned aerial vehicle (UAV), such as a drone. TDD is particularly well-suited for this use due to the typical asymmetry of uplink communication (from controller to UAV) compared to downlink communication (from UAV to controller).

[0042] An embodiment of the present invention interferes with a time-division duplex communication link between two nodes in order to disconnect the connection between the two nodes. The objective is to carry out this disconnection with minimal interference to other communication links in the area.

[0043] Before detailing at least one embodiment of the present invention, it should be understood that the present invention is not necessarily limited in its application to the construction details and arrangement of components and / or methods specified in the following description and / or shown in the drawings and / or examples. The present invention can be put into other embodiments or practiced or implemented in various ways.

[0044] The present invention may also be a system, method, and / or a computer program product. The computer program product may include one or more computer-readable storage media having computer-readable program instructions for causing a processor to carry out aspects of the present invention.

[0045] A computer-readable storage medium can be a tangible device capable of holding and storing instructions for use by an instruction-executing device. A computer-readable storage medium may be, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination thereof. A non-exhaustive list of more specific examples of computer-readable storage media includes: portable computer diskettes, hard disks, random-access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random-access memory (SRAM), portable compact disk read-only memory (CD-ROM), digital multipurpose disks (DVDs), memory sticks, floppy disks, mechanically encoded devices such as punch cards or grooves on which instructions are recorded, and any suitable combination thereof. In this specification, a computer-readable storage medium should not be interpreted as a transient signal itself, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmitting medium (for example, a pulse of light passing through an optical fiber cable), or an electrical signal transmitted through a wire.

[0046] The computer-readable program instructions described herein can be downloaded to each computing / processing device from a computer-readable storage medium or to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network may include copper transmission cables, optical transmission fibers, wireless transmitters, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface within each computing / processing device receives computer-readable program instructions from the network and transfers the computer-readable program instructions for storage in a computer-readable storage medium within each computing / processing device.

[0047] The computer-readable program instructions for performing the operation of the present invention may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including smalltalk, object-oriented programming languages ​​such as C++, and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The computer-readable program instructions may be executed in whole on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer and partially on a remote computer, or in whole on a remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or wide area network (WAN), or the connection may be made to an external computer (for example, via the Internet using an Internet service provider). In some embodiments, an electronic circuit, including, for example, a programmable logic circuit, a field-programmable gate array (FPGA), or a programmable logic array (PLA), can execute a computer-readable program instruction by personalizing the electronic circuit using state information of the computer-readable program instruction in order to carry out an aspect of the present invention.

[0048] Aspects of the present invention will be described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present invention. It will be understood that each block in the flowchart illustrations and / or block diagrams, and combinations of blocks within the flowchart illustrations and / or block diagrams, can be implemented by computer-readable program instructions.

[0049] These computer-readable program instructions may be provided to a processor of a general-purpose computer, a dedicated computer, or another programmable data processing device to generate a machine, so that instructions executed via the processor of a computer or other programmable data processing device create means for implementing a function / activity specified in one or more blocks of a flowchart and / or block diagram. These computer-readable program instructions may also be stored in a computer-readable storage medium that can instruct a computer, a programmable data processing device, and / or other device to function in a particular manner, so that the computer-readable storage medium on which the instructions are stored comprises a product containing instructions that implement a mode of function / activity specified in one or more blocks of a flowchart and / or block diagram.

[0050] Computer-readable program instructions can also be loaded into a computer, another programmable data processing device, or another device to cause the computer, another programmable device, or another device to execute a series of operational steps to produce a computer-implemented process, so that the instructions executed by the computer, another programmable device, or another device implement the functions / activities specified in one or more blocks of a flowchart and / or block diagram.

[0051] Figure 1, which illustrates an exemplary scenario for interfering with a TDD communication link between two nodes, is referenced here. Node A110 transmits frequency-hopping packets to Node B120. Node B120 transmits fixed-frequency packets to Node A110. Nodes B120 and A110 transmit at different time frames. Disconnection device 130 transmits signals received by Node B120 and signals from Node A110 designed to disconnect Node B120. Normally, transmissions from Node B120 are received by disconnection device 130, but transmissions from Node A110 are not received and therefore cannot be analyzed by disconnection device 130.

[0052] For clarity, the description herein presents non-limiting exemplary embodiments in which the TDD communication link is between two nodes (referred to herein as Node A and Node B), and it is desirable to disconnect Node B from Node A. It will be understood by those skilled in the art that other embodiments of the invention can be implemented for TDD communication links having more than two nodes (for example, a single controller controlling multiple drones or multiple controllers controlling multiple drones).

[0053] I. Methods for interfering with TDD communication links Figure 2, a simplified flowchart of a method for disconnecting a wireless time-division duplex communication link according to an embodiment of the present invention, is referenced herein. The time-division duplex (TDD) communication link is between a first node (referred to herein as node A) transmitting during a time slot assigned to node A and a second node (referred to herein as node B) transmitting during a separate time slot assigned to node B.

[0054] In this specification, the term "separate time slots" means that the time slot of node A does not overlap with the time slot of node B.

[0055] Node A transmits across multiple frequency bands. During each of its allocated time slots, Node A transmits across each of these frequency bands. Node A may transmit in a fixed hop pattern (i.e., in a predetermined repeating order), or the frequency bands used by Node A's transmissions may vary in different ways. The frequency bands used by Node A should be known or discoverable by Node B so that Node B can accurately receive Node A's transmissions.

[0056] In 210, the time slot assigned to the first node is further divided into continuous time intervals. The method for identifying or determining the node A time slot will be described later.

[0057] In this specification, the term “continuous time interval” means that the time interval is in a non-overlapping sequence that begins at the start of a time slot and ends at the end of a time slot. Optionally, the time interval duration is the same for each time slot in node A. Alternately, some or all of the time slots are divided into sequences with different time interval durations.

[0058] In 220, each disconnection signal is transmitted during some or all of the time intervals. Each disconnection signal is transmitted in one of the frequency bands of node A. The disconnection signals are transmitted in different frequency bands during at least two of those time intervals. Optionally, when the frequency band of node A is not precisely known, the disconnection signal is transmitted in the frequency band that node A is expected to use.

[0059] Optionally, for a single node A time, the disconnected signal covers the entire frequency range used by node A.

[0060] Optionally, each frequency band of the disconnected signal is selected from a list of frequency band specifications. The list may include frequency bands known to be used by Node A. This technique is useful when Node A transmits in a specific frequency band within its entire frequency range, rather than transmitting across a continuous frequency range.

[0061] In this specification, the term “integrated disconnection signal” means the entire disconnection signal transmitted within a single time slot. The integrated disconnection signal is constructed from multiple short disconnection signals transmitted during each time interval within a single time slot. The integrated disconnection signal may be constructed in the same manner for all Node A time slots, or in different manner for different time slots. For example, in some Node A time slots, the integrated disconnection signal may encompass the entire frequency range of Node A, while in other time slots, only a portion or some portion of the frequency range of Node A may be interfered with.

[0062] Optionally, a single disconnected signal (i.e., a signal in a single frequency band) is transmitted at each time interval, and therefore the transmitted power is concentrated in one frequency band.

[0063] Figure 3A shows an exemplary embodiment in which a Node A transmission is interfered with by a staggered transmission of a disconnected signal during a Node A time slot. The Node A time slot is further divided into N time intervals. A single disconnected signal is transmitted during each time interval. If the frequency band of Node A (F1-FN) encompasses a continuous frequency range, then the integrated disconnected signal encompasses the entire frequency range. If F1-FN is part of the entire frequency range of Node A, then the integrated disconnected signal interferes with the frequency band used by all Node A. In Figure 3A, the frequency bands of the integrated disconnected signal are transmitted in the same order during each Node A time slot.

[0064] Figure 3B shows an exemplary embodiment in which node A sends multiple packets at different phases but at a constant period. As shown in Figure 3A, node A transmissions are interfered with by staggered transmissions of disconnection signals during node A time slots.

[0065] Figure 4 shows an alternative, exemplary embodiment in which the order of frequency bands within the integrated cut signal differs for different node A time slots.

[0066] Alternately, multiple disconnect signals are transmitted in parallel during at least one of the time intervals. Figure 5 shows an example where two disconnect signals in different frequency bands are transmitted during any given time interval. Parallel transmission across multiple frequency bands can be useful when the number of available time intervals in a single Node A time slot is less than the number of Node A frequency bands. To cover all of Node A frequency bands within a single Node A time slot, it is necessary to transmit on multiple frequency bands in a given time interval. This technique can also be beneficial when the available transmit power is high enough to interfere with multiple frequency bands in parallel (for example, when a Node B transmission is received at high power indicating that Node B is nearby).

[0067] Optionally, only a subset of Node A frequency bands is interfered with by a disconnection signal during a single Node A time slot, while a second subset of Node A frequency bands is interfered with between different Node A time slots. As mentioned above, this may be useful when the number of available time intervals in a single Node A time slot is less than the number of Node A frequency bands. This embodiment is also useful when some knowledge exists regarding the possible frequency bands that Node A may transmit. Assigning frequency bands to time intervals in an integrated time signal can be done by any means known in the art. Examples of assigning frequency bands to time intervals include, but are not limited to, the following: i) Predefined order, ii) Follow the specified rules, and, iii) Randomly.

[0068] The allocation may take into account additional information, such as known information about the TDD communication link and / or information gathered by analyzing transmissions received from Node B.

[0069] In some embodiments, node A transmits in a known hop pattern. The order of frequency bands used by node A is known, but node A transmissions are not received, and therefore it is not known which frequency bands are currently in use. This additional information can be used to select an interfering signal. An optional embodiment involves rapidly modifying and transmitting the disconnect signal based on the known hop pattern using partial frequencies from the list to further increase the disconnect signal power. For example, suppose the frequency order of node A is known to be F1, F2, F3, ..., FN. Then F1, F2, F3, F4, and F5 may be transmitted together in one integrated disconnect signal in parallel with a first node A packet, and F2, F3, F4, F5, and F6 may be transmitted together with a second integrated disconnect signal in parallel with a second node A packet. If disconnection is not achieved after some time, the next sequence may be modified.

[0070] In this way, because less cutting signal is required to achieve the cut, precise phase is ultimately achieved with higher power.

[0071] II. Types of disconnection signals In many TDD communication links, a "disconnect command" can be issued from one node to another. The disconnect command informs the receiver that the connection has been terminated. The receiving node then terminates its own connection. In some cases, the nodes will then attempt to re-establish their connection at the same or a different timing phase. This type of communication can be disrupted by sending a disconnect signal that carries the disconnect command to node B. When the disconnect signal is received by node B at a higher signal-to-noise ratio (SNR) than the node A packet, node B can demodulate the disconnect signal instead of sending the packet from node A. This will break the link between node A and node B.

[0072] Optionally, during at least one of the time intervals, the disconnect signal is a data-modulated carrier signal. Further optional, the disconnect signal carries one or more data packets constructed according to the TDD communication link protocol.

[0073] Optionally, one or more of the disconnect signals are modulated by one or more disconnect commands at node B. The disconnect commands are constructed according to a known protocol between node A and node B. The disconnect signals are typically short signals, preferably shorter than TA / N (where TA is the node A slot time and N is the number of known frequencies). If the shortest disconnect signal time Tdis is longer than TA / N, then it is necessary to transmit the disconnect signals in parallel at k=floor(N·Tdis / TA) to cover all of the node A frequencies.

[0074] In some cases, for example, when the disconnection length is too long or the protocol between node A and node B is unknown, a different type of disconnection signal may be used. In this case, disconnection is achieved by reducing the signal-to-noise ratio (SNR) of node B's reception of node A's signal. This results in a high bit error rate (BER), which ultimately leads to the entire packet or frame failing due to a failure in parity checking.

[0075] Other types of disconnection signals include, but are not limited to, the following: a) Noise signals, for example, a predefined noise pattern, random noise or white Gaussian noise signal, b) Predefined jamming signal, c) Modulated pseudo-random binary sequences, which optionally use constant-encompassing routes such as BPSK, and d) A predefined binary sequence modulated as a constant-encompassing path signal (e.g., an arbitrary phase-shifted keying signal).

[0076] Using noise or PSK disconnect signals is beneficial when node B cannot receive packets from node A due to parallel reception of packets.

[0077] An integrated disconnect signal for a single time slot can be represented as follows: J(t) = N(t)·cos(2πf(t)t+φ) Here, N(t) is the unified cut signal, f(t) is the carrier frequency, and φ is constant or random phase. Optionally, N(t) is one of the following: i) A sequence of M packets containing protocol-specific commands for disconnection, and ii) A predefined pattern (e.g., white Gaussian noise, modulated pseudo-random binary sequence, any modulated binary sequence, or any predefined jamming signal).

[0078] Regarding the changing carrier frequency f(t) at node A: A) Embodiments in which the disconnected signal carrier frequency is a line sequence {f0 + n·Δf}:

number

number

[0079] As shown in Figure 4, the order of frequencies within the integrated disconnected signal may differ for transmissions in different time slots.

[0080] III. Cutting device A simplified block diagram of a disconnection device for disconnecting a wireless time-division duplex communication link according to an embodiment of the present invention is shown here with reference to Figure 6. As previously mentioned, the TDD communication link is between node A, which transmits at different frequencies during its allocated time slots, and node B, which transmits at a fixed frequency during its time slots.

[0081] The cutting device 600 includes a signal generator 610 and a wireless transmitter 620.

[0082] The signal generator 610 generates an integrated disconnect signal for each node A time slot by further dividing the time slot assigned to the first node into continuous time intervals and generating disconnect signals for each of the multiple time intervals. Each disconnect signal occupies each of the node A frequency bands, so that during at least two of the time intervals, the disconnect signals occupy different frequency bands.

[0083] In order to interfere with communication between Node A and Node B, the integrated disconnection signal generated by signal generator 610 is transmitted by transmitter 620 during each Node A time slot in parallel with the Node A transmission.

[0084] Those skilled in the art will understand that the signal generator 610 may be used to generate any of the disconnect signals and to integrate the disconnect signals described herein, as required by a particular embodiment. For example, in some embodiments, multiple disconnect signals (in different frequency bands) are transmitted during a single time interval.

[0085] Optionally, for at least one of the time intervals, the disconnected signal is the carrier frequency in each frequency band, where the carrier signal is modulated by one of the following: a) Disconnect command for the second node (or, if several exist, one of several optional disconnect commands), b) Noise signals, for example, a predefined noise pattern, random noise or white Gaussian noise signal, c) Predefined jamming signal, d) Using a fixed-envelope route such as BPSK at the optional rate, a pseudo-random binary sequence, and e) A predefined binary sequence (modulated as a constant-encompassing signal, e.g., an arbitrary phase-shifted keying signal).

[0086] Optionally, during a given time slot, the signal generator 610 selects each frequency band of the disconnected signal from a list of known frequency bands used by node A. Alternatingly or additionally, during a given time slot, the signal generator 610 selects each frequency band of the disconnected signal as a continuous frequency band across the frequency range used by node A.

[0087] Optionally, the entire frequency range used by Node A during a single Node A time slot is interfered with by a cut-off signal.

[0088] In the embodiment shown in Figure 6, the signal generator 610 and transmitter 620 are a single device. In an alternative embodiment, the signal generator 610 is an add-on unit that provides an integrated disconnected signal to a standalone transmitter.

[0089] IV. Monitor Node B communication. Optionally, Node B communications are monitored and analyzed to collect information about communications between Node A and Node B and / or parameters of the TDD communication link. Node B transmissions may be monitored and / or analyzed continuously or intermittently.

[0090] Several Node B transmissions can be collected and analyzed to predict an approaching Node A time slot. The prediction can also be based on prior knowledge, such as that Node A is transmitting packets at a fixed period or that Node A is transmitting several packets at a fixed period (for example, two phases with a 10-millisecond period, at 10n milliseconds and 10n+4 milliseconds).

[0091] The types of information that may be obtained through this analysis include, but are not limited to, the following: 1) Identify the disconnection between node A and node B. Optionally, when the disconnection is identified, direct communication is established with node B (for example, by sending a connection request to node B). 2) Identify and / or predict the time slots assigned to Node A and / or Node B. Knowledge of the start and / or end times of the time slots enables the transmission of disconnection signals at precise times. 3) Communication protocols used by nodes A and B, and 4) Management of Node A and Node B time slots (see, for example, Figures 7A-7C).

[0092] It is desirable to transmit an integrated disconnection signal during the time slot of the node A constructed for this purpose. Numerous ways of allocating time slots in TDD are known in the art. The embodiments presented herein are not limited to any particular type of slot allocation by TDD communication link.

[0093] The start of Node A's time slot is detected when Node B sends a reconnection request, either alternately or in addition. Node B's transmission is optionally analyzed to determine the protocol used by the TDD communication link, so that the reconnection request can be identified in Node B's transmission.

[0094] The decision of when to begin transmitting the integrated disconnection signal may be based more on the following: 1) Detecting the start and / or end of Node B transmissions. Several Node B transmissions may be collected and analyzed together to "learn" time slot patterns and predict in advance upcoming Node A time slots (e.g., transmit packet times). This may block signals (e.g., ACK responses) sent by Node A at the start of its time slot. 2) Identify the transmission of data sent by Node B (e.g., reconnection requests, ACK packets, disconnection commands, etc.). 3) Prior knowledge of access schemes.

[0095] Exemplary examples include: 1) The integrated disconnection signal is sent at a predefined time after node B has finished transmitting. As shown in Figure 7A, this method is effective when node B is the master, manages the frame time, and node A responds to node B. 2) The integrated disconnection signal is sent at a predefined time before the predicted node B time slot. This technique is effective in the timing scenarios shown in Figures 7B and 7C. In Figure 7B, node A is the master, and node B responds to node B, usually after a relatively short buffer time. Figure 7C shows an example where the period time, T, and slot times, TA and TB, are determined in advance, for example, when the link is established. If this pattern is known, the timing of future time slots is known after the node A or node B time slot has been identified.

[0096] V. Controlling the cutting device A simplified flowchart of a method for controlling a disconnection device interfering with wireless time-division duplex communication, according to an embodiment of the present invention, is referenced herein, Figure 8. This control is based on information gathered by receiving and analyzing signals transmitted by node B.

[0097] At 810, the wireless transmission is received from node B.

[0098] In 820, the approaching node A time slot is determined based on the received transmission. An optional technique for performing this determination has been described previously (for example, identifying the end of node B time slot by prior knowledge of the timing of the time slot).

[0099] At 830, the approaching node A time slot is further divided into continuous time intervals.

[0100] In 840, the cutting device is instructed to transmit during the node A time slot determined in 820, and the integrated cutting signal is constructed based on the respective frequency bands assigned to the time intervals within the time slot. The frequency band assignments may be designed to produce any type of one or more of the integrated cutting signals described herein, as required by a particular embodiment.

[0101] Optionally, the command to the cutting device includes at least one signal parameter for generating a cutting signal. The signal parameter for generating a cutting signal includes, but is not limited to, the following: i) The type of disconnection signal to send, ii) Data for modulating the disconnection signal, iii) Duration of the time slot, iv) The duration of each time interval, v) Each frequency band of the disconnection signal, vi) The transmission power of each disconnection signal, and vii) The number of disconnection signals to be transmitted in parallel.

[0102] Optionally, the cutting device is instructed to modulate the cutting command into at least one of the cutting signals.

[0103] Optionally, the method further includes detecting when nodes A and B are disconnected (for example, the TDD communication link is successfully interfered with). The disconnection device is then instructed to establish direct communication with node B. Optionally, communication is established with node B by sending a connection request to node B at high power.

[0104] VI. Controller of the cutting device A simplified block diagram of a controller for a wireless disconnection device according to an embodiment of the present invention is shown herein, with reference to Figure 9. The controller 900 includes a receiver 910 and a signal analyzer 920, which together implement the method shown in Figure 8.

[0105] Receiver 910 receives a wireless transmission from node B. Signal analyzer 920 analyzes the received signal to determine the approaching time slot assigned to node A and to further divide the node A time slot into continuous time intervals. Signal analyzer 920 also instructs the cutting device on how the integrated cutting signal should be constructed and when it should be transmitted.

[0106] Optionally, receiver 910 performs analog and / or digital processing on the received signal before providing it to signal analyzer 920. For example, receiver 910 may include an analog-to-digital converter that converts the received node B signal into a digital signal to be analyzed by signal analyzer 920.

[0107] In the embodiment shown in Figure 9, the receiver 910 and the signal analyzer 920 are a single device. In an alternative embodiment, the signal analyzer 920 is an add-on unit that provides an integrated disconnected signal to a standalone transmitter.

[0108] VII. Exemplary Cutting Device Figure 10, a simplified block diagram of a cutting device according to an exemplary embodiment of the present invention, is referenced herein. The cutting device 1000 includes the components shown in Figures 6 and 9. Receiver 1010 receives a signal transmitted by node B. Signal analyzer 1020 analyzes the received signal and determines the approaching node A time slot and / or how the integrated cutting signal should be constructed for the node A time slot. These instructions are provided to signal generator 1030, which generates an integrated cutting signal for transmission by wireless transmitter 1040.

[0109] The combined operation of the signal analyzer 1020 and the signal generator 1030 can perform any of the analyses described herein and generate either a cut signal or an integrated cut signal as described herein. For brevity, the complete details of all possible embodiments are not repeated, but they are provided by the cut device 1000.

[0110] In the embodiment shown in Figure 10, the receiver 1010, signal analyzer 1020, signal generator 1030, and transmitter 1040 form a single device. In alternative embodiments, the receiver and / or transmitter are external. Note that the interference signal may also be a disconnection signal intended to separate the first node from the second node. Note that the interference signal may be different from the disconnection signal.

[0111] Sending spectral mask compliance Interfering signals can be transmitted in urban environments, near airports, or in any environment where a transmit spectrum mask is imposed—therefore limiting disruption to unrelated systems.

[0112] It has been discovered that transmitted spectral mask compliance can be obtained by imposing one or more restrictions on the frequency difference between members of a pair of continuous interfering signals.

[0113] Additionally or by alternative means, transmitted spectral mask compliance can be obtained by imposing one or more limitations on the frequency change rate between members of a pair of continuous interfering signals.

[0114] Any limit may be provided as an absolute value or may be defined differently—for example, it may relate to the number of frequency bands used by the first node.

[0115] The frequency difference can be calculated based on the difference in the frequency bands from which members of a pair of continuous interfering signals are transmitted.

[0116] A continuous interference signal may be transmitted to interrupt communication between a first node and a second node using a time-division duplex communication link. The transmission occurs during time slots assigned to the first node, where the second node transmits during separate time slots assigned to the second node, and the first node transmits in each of a plurality of frequency bands during each of the time slots assigned to the first node.

[0117] It should be noted that time slots can be further divided into continuous time intervals.

[0118] An interruption signal can be transmitted during all consecutive time intervals, or not transmitted during any consecutive time intervals, or simply during one of several consecutive time intervals.

[0119] A pair of members of a continuous interference signal may be transmitted during a pair of continuous time intervals.

[0120] Alternatively, members of a pair of continuous interference signals may be transmitted between a pair of discontinuous time intervals.

[0121] Therefore, one or more gaps in continuous time intervals may exist between members of a pair of continuous interference signals. Such gaps can reduce the rate of frequency change. The gaps may be determined based on the frequency difference between the frequency bands of the members of a pair of continuous interference signals and based on frequency rate change limits.

[0122] As described above, the first node transmits in each of the multiple frequency bands during each of the time slots assigned to the first node.

[0123] The interrupt signal may be transmitted in any one of the multiple frequency bands, but may also be transmitted in at least one additional frequency band that does not belong to any of the multiple frequency bands.

[0124] Additional frequency bands may be used to fill gaps between frequency bands (among multiple frequency bands) and / or to accommodate frequency rate change limitations.

[0125] The frequency bands in which interrupt signals are transmitted may form a group of frequency bands.

[0126] It should be noted that multiple frequency bands can form one or more subsets of a frequency band.

[0127] The frequency gap between multiple subsets may exceed the width of the subset—which is the difference between the highest and lowest frequencies of the subset. In such cases, the interrupted signal may be grouped into multiple groups of frequency bands—for example, one group for each spaced-out subset.

[0128] One of the main attributes that can affect the spectral mask is how the signal changes between hops. Signal characteristics, such as the rise and fall times of radio signals or fast frequency transitions, can affect the overall spectral mask and force transmitters to reduce power to comply with spectral mask requirements, potentially causing momentarily high bandwidth.

[0129] When there are fast hop-to-hop transitions at different frequencies, several methods exist for handling the transitions to ensure a low spectral mask—two of which are listed below.

[0130] A transition from one interfering signal (one hop) to an adjacent interfering signal (a second hop) can involve a smooth transition between the two hops through continuous transmission of the signals, and a slow change in frequency during the transition between the two hops. Frequency changes can be linear, i.e., by linearly changing the signal frequency between signals (for example, by linearly changing the VCO or NCO input). However, frequency changes can also be performed using other transition functions between the two frequencies, such as a Gaussian step, cosine step, or any other continuous function from one frequency to the other.

[0131] The transition from one interference signal (one hop) to an adjacent interference signal (a second hop) may involve slowly decreasing the power of one hop and increasing the power of the next hop using a window, such as a triangular window, Hamming window, Hann window, square cosine window, Gaussian window, Kaiser window, or any other type of window for those familiar with the art. As long as the total power is kept below some limited maximum value, the falling time of the first hop and the rising time of the second hop may occur consequently, but may also occur in parallel.

[0132] A simplified flowchart of a method 2000 for disconnecting a wireless time-division duplex communication link according to an embodiment of the present invention is shown here with reference to Figure 11. The time-division duplex (TDD) communication link is between a first node (referred to herein as node A) transmitting during a time slot assigned to node A and a second node (referred to herein as node B) transmitting during a separate time slot assigned to node B.

[0133] In this specification, the term "separate time slots" means that the time slot of node A does not overlap with the time slot of node B.

[0134] Node A transmits across multiple frequency bands. During each of its allocated time slots, Node A transmits across each of these frequency bands. Node A may transmit in a fixed hop pattern (i.e., in a predetermined repeating order), or the frequency bands used by Node A's transmissions may vary in different ways. The frequency bands used by Node A should be known or discoverable by Node B so that Node B can accurately receive Node A's transmissions.

[0135] Method 2000 may be initiated by step 210.

[0136] In step 210, the time slot assigned to the first node is further divided into continuous time intervals. A method for identifying or determining the node A time slot will be described later.

[0137] Step 210 may be followed by Step 2020.

[0138] Step 2020 may include interrupting communication between the first node and the second node by transmitting each interference signal using a transmitter during at least some of the time intervals, each of which interference signals is transmitted in one frequency band selected from the group of frequency bands, the group of frequency bands comprising multiple frequency bands, where the interference signals are transmitted in different frequency bands over at least two of the time intervals.

[0139] The transmission includes imposing one or more limits on the frequency difference between members of a pair of continuous interfering signals and / or imposing one or more limits on the frequency change rate between members of a pair of continuous interfering signals.

[0140] One example of one or more frequency difference limits includes: (i) transmission can be performed while maintaining a frequency difference between any pair of continuous interfering signals below a frequency difference threshold, and (ii) the frequency difference threshold does not exceed a portion of the frequency gap between (a) the lowest frequency band of a plurality of frequency bands and (b) the highest frequency band of a plurality of frequency bands.

[0141] One example of one or more frequency change rate limits may include: (i) transmission can be performed while maintaining a frequency change rate difference between any pair of continuous interfering signals below a frequency change rate difference threshold; and (ii) the frequency change rate difference threshold does not exceed the ratio of (i) the portion of the frequency gap between (a) the lowest frequency band of the multiple frequency bands and (b) the highest frequency band of the multiple frequency bands, and (ii) the duration of the time interval.

[0142] In 2020, each disconnection signal is transmitted during some or all of the time interval. Each disconnection signal may be in one of the frequency bands of the group. A group may include multiple frequency bands. A group may include additional frequency bands. A group may be limited to multiple frequency bands.

[0143] Step 2020 is performed while imposing one or more limits on the frequency difference between members of a pair of continuous interference signals and / or one or more limits on the rate of frequency change between members of a pair of continuous interference signals.

[0144] For example, step 2020 may impose the following limitations on frequency differences: For example, a transmission may be performed while maintaining a frequency difference between any pair of continuous interfering signals below a frequency difference threshold. The frequency difference threshold does not have to exceed a portion of the frequency gap between (a) the lowest frequency band of a plurality of frequency bands and (b) the highest frequency band of a plurality of frequency bands. This portion may be (1 / X) of the frequency gap, where x may exceed, for example, 1.5, 2, 4, 6, 7, 9, 10, 12, and even larger numbers.

[0145] The disconnection signal is transmitted in different frequency bands during at least two of those time intervals. Optionally, when the frequency band of node A is not precisely known, the disconnection signal is transmitted in the frequency band expected to be used by node A.

[0146] Optionally, for a single node A time, the disconnected signal covers the entire frequency range used by node A.

[0147] Optionally, each frequency band of the disconnected signal is selected from a list of frequency band specifications. The list may include frequency bands known to be used by Node A. This technique is useful when Node A transmits in a specific frequency band within its entire frequency range, rather than transmitting across a continuous frequency range.

[0148] In this specification, the term “integrated disconnection signal” means the entire disconnection signal transmitted within a single time slot. The integrated disconnection signal is constructed from multiple short disconnection signals transmitted during each time interval within a single time slot. The integrated disconnection signal may be constructed in the same manner for all Node A time slots, or in different manner for different time slots. For example, in some Node A time slots, the integrated disconnection signal may encompass the entire frequency range of Node A, while in other time slots, only a portion or some portion of the frequency range of Node A may be interfered with.

[0149] Optionally, a single disconnected signal (i.e., a signal in a single frequency band) is transmitted at each time interval, and therefore the transmitted power is concentrated in one frequency band.

[0150] Regarding Step 2020 - at least one of the following is true:

[0151] The portion shall not exceed the value obtained by dividing a specific value (e.g., 2 or 4) by the number of frequency bands among the multiple frequency bands. The specific value may be different from 2 or 4—but it may be chosen so that the portion is less than the frequency gap.

[0152] • Frequency bands associated with different time intervals can form various patterns—for example, one or more sets of ascending frequency bands and / or one or more sets of descending frequency bands and / or one or more sets of fixed frequency bands.

[0153] • Different sets of frequency bands may have the same duration (within the same time interval) and / or the same number of members.

[0154] • Different sets of frequency bands may differ from one another by at least one of their durations (within a time interval) and / or by the number of members.

[0155] The frequency bands of different sets may be within the same range (the difference between the lowest and highest frequencies of the set) or they may be within different ranges.

[0156] A single frequency band can begin with one set and end with another.

[0157] A single frequency band can belong to a single frequency band.

[0158] • A continuous time interval may include a continuous time interval of the first group and a continuous time interval of the second group.

[0159] Interrupting may include transmitting a first set of interfering signals in ascending frequency bands during a continuous time interval of a first group, and transmitting a second set of interfering signals in descending frequency bands during a continuous time interval of a second group.

[0160] Each of the frequency bands in ascending order is different from each of the frequency bands in descending order.

[0161] For at least some of the ascending frequency bands, the frequency band lies between a pair of consecutive descending frequency bands.

[0162] The ordered list of ascending frequency bands and the reversed list of descending frequency bands form an alternating sequence of frequency bands, and the ordered list is ordered according to the transmission time.

[0163] • The continuous interference signal of the first set exhibits a frequency gap that is not less than twice the frequency gap between continuous frequencies among the multiple frequency bands.

[0164] • An ascending ordered list of frequency bands may contain a subset of consecutive frequency bands from among multiple frequency bands, where the consecutive subsets are spaced by frequency gaps no less than twice the frequency gap between consecutive frequencies from among the multiple frequency bands.

[0165] • A continuous time interval includes one or more additional time intervals in addition to the continuous time intervals of the first group and the continuous time intervals of the second group.

[0166] Interrupting may involve transmitting interruption signals in some or more of the ascending frequency bands during an additional time interval.

[0167] Interrupting may involve transmitting interruption signals in some or more descending frequency bands during an additional time interval.

[0168] Interruption may include transmitting one or more interruption signals in one or more frequency bands that do not belong to the ascending frequency bands and descending frequency bands during an additional time interval.

[0169] The frequency gap between the consecutive ascending frequency gaps of each pair is equal to the frequency gap between the consecutive descending frequency bands of each pair.

[0170] • The continuous time intervals of the first group precede the continuous time intervals of the second group.

[0171] The continuous time intervals of the first group are followed by the continuous time intervals of the second group.

[0172] • A descending ordered list of frequency bands may contain a subset of consecutive frequency bands from among multiple frequency bands, where the consecutive subsets are spaced by frequency gaps no less than twice the frequency gap between consecutive frequencies from among the multiple frequency bands.

[0173] • The second set of continuous interference signals exhibits a frequency gap that is not less than twice the frequency gap between continuous frequencies among multiple frequency bands.

[0174] • Randomly select at least some of the transmission bands from a range of frequency bands.

[0175] - Randomly selecting at least some of the transmission bands from multiple frequency bands, while imposing predefined scope conditions for the time slots within the frequency band.

[0176] • Deviating from a predefined transmission scheme following the occurrence of an event.

[0177] - The event may include transmission and synchronization between the first node and the second node.

[0178] - An event may include locking onto signals exchanged over a communication link.

[0179] Transmitting may involve transmitting an interference signal of at least one pair of continuous interference signals during a continuous time interval.

[0180] Transmitting may involve transmitting an interference signal between at least one pair of continuous interference signals during a time interval with a gap between them.

[0181] • Transmit the first interference signal during the first time interval.

[0182] • Avoid transmitting interfering signals between one or more intermediate time intervals.

[0183] • A second interference signal is transmitted during the second time interval, so that the first time interval, one or more intermediate time intervals, and the second time interval form a continuous sequence of time intervals.

[0184] The group may include multiple frequency bands and at least one additional frequency band.

[0185] • A group may only include multiple frequency bands.

[0186] The method may include deciding to use a frequency band of a different group and interrupting communication between the first node and the second node that use a frequency band of the other group.

[0187] The use of other group frequency bands may include interrupting communication between the first node and the second node by transmitting, using a transmitter, each of the interfering signals for at least some of the time intervals, while maintaining a frequency difference between any pair of continuous interfering signals below a frequency difference threshold, each of which is transmitted in one frequency band selected from the other group frequency bands, and the other group frequency bands may include multiple frequency bands.

[0188] • Deciding to use the frequency bands of other groups in response to the occurrence of an event.

[0189] • Deciding to use the frequency bands of other groups based on a predefined schedule.

[0190] • Alternating between multiple groups of frequency bands.

[0191] Transmitting in a simple gradual series while performing modulo on the channel numbering sequence: Ch(n) = Ch(0) + (delta*n) mod N Here, Ch(n) is the sequential number of the channel used in time slot = n, Ch(0) is set to one of the possible index values ​​{0, ..., N-1}, and N is the number of channels in the group of possible frequency bands used by the first node. delta is the difference of the sequential numbers of the channels used in the continuous interrupt signal, which can be any integer. To ensure that all channel numbers are used, delta should satisfy GCD(delta, N) = 1.

[0192] • Transmission in the same series expected by the second node.

[0193] If the specific phase of the first node is unknown, several hypotheses about this phase can be attempted, and different series can be tried.

[0194] • Transmission using ascending even frequency bands (when frequency bands are ordered) followed by transmission using descending odd frequency bands.

[0195] For example, transmitting interruption signals in the following frequency bands: - FB(0), FB(2), FB(4), ..., FB(N-4), FB(N-2), FB(N-1), FB(N-3), ..., FB(3), FB(1) (N is an even number) - FB(0), FB(2), FB(4), ..., FB(N-3), FB(N-1), FB(N-2), FB(N-4), ..., FB(3), FB(1) (N is an odd number) - FB(1), FB(3), FB(5), ..., FB(N-3), FB(N-1), FB(N-2), FB(N-4), ..., FB(2), ..., FB(0) (N is an even number) - FB(1), FB(3), FB(5), ..., FB(N-4), FB(N-2), FB(N-1), FB(N-3), ..., FB(2), FB(0) (N is an odd number) Therefore, FB(n) is the nth frequency band in the group of frequency bands used by the first node when the frequency bands are ordered in ascending order.

[0196] • When one or more of the frequency bands are transmitted multiple times per cycle, transmit an interruption signal using the aforementioned series of frequency bands.

[0197] • Transmitting interruption signals using randomly selected frequency bands in no particular order. However, the randomness may be modified to prevent deviations from frequency and / or frequency change rate limits.

[0198] - Transmitting an interruption signal using a specific sequence of frequency bands and changing the sequence of the frequency bands at one or more cycles (one of the aforementioned)

[0199] Transmitting various types of transition signals, such as linear frequency change signals ("chirps"), which can result in failure to adhere to the transmit spectral mask, for example, to smooth the transmission and avoid fast ramps in the signal.

[0200] Figures 12-14 show examples of interrupt signals transmitted during time intervals. The X-axis represents the transmission time, and the Y-axis represents the frequency band.

[0201] The timing diagram 2110 in Figure 12 shows multiple 16 frequency bands and two iterations: a first set 2111 of interference signals in ascending frequency bands (even frequency bands) and a second set 2112 of interference signals in descending frequency bands (odd frequency bands). Note that the ascending frequency bands may include odd frequency bands, and the descending frequency bands may include even frequency bands.

[0202] Timing diagrams 2120 and 2130 show multiple 16 frequency bands and different combinations of the ascending frequency subset 2121 and the descending frequency subset 2122.

[0203] A subset of frequencies in ascending order may belong to a set of frequencies in ascending order or to a set of frequencies in descending order—and the same may apply to a set of frequencies in descending order, with the necessary modifications.

[0204] The timing diagram 2140 in Figure 13 shows the transmission of signals in multiple eight frequency bands 2141 spaced apart from each other, and an additional frequency band (not part of the eight frequency bands) 2142—for example, to maintain frequency difference limits.

[0205] The timing diagram 2150 in Figure 13 shows a number of eight frequency bands 2151 spaced apart from each other, and a time gap 2153 between the transmission of two consecutive interrupt signals—for example, introduced to comply with a frequency change rate limit (the rate is shown by the dashed line 2154).

[0206] The timing diagram 2170 in Figure 14 shows the transmission of signals in a plurality of 16 frequencies arranged in two frequency spaces 2171 and 2172 that are separated from each other, and in an additional frequency band (not a portion of the 8 frequency bands) 2153—for example, to maintain frequency difference limits.

[0207] The timing diagram 2160 in Figure 14 shows a plurality of 16 frequencies arranged in two frequency spaces 2171 and 2172 that are separated from each other, and a time gap 2173 between the transmission of two consecutive interrupt signals—for example, introduced to comply with a frequency change rate limit.

[0208] The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this context, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. Note that in some alternative implementations, the functions described in a block may occur in an order other than that shown in the figure. For example, two consecutively shown blocks may actually be executed substantially simultaneously, or they may sometimes be executed in reverse order depending on the relevant functionality. Note that each block in a block diagram and / or flowchart illustration, and any combination of blocks in a block diagram and / or flowchart illustration, may be implemented by a dedicated hardware-based system or a combination of dedicated hardware and computer instructions to perform a specified function or activity.

[0209] The descriptions of various embodiments of the present invention are presented for illustrative purposes only and are not intended to be exhaustive or to limit oneself to the disclosed embodiments. Numerous modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein has been selected to best describe the principles of the embodiments, the actual applications or the technical improvements compared to the technology available on the market, or to enable those skilled in the art to understand the embodiments disclosed herein.

[0210] It is anticipated that during the term of this patent, which matures from this application, numerous related TDD communication links, communication protocols, and nodes communicating via TDD communication links will be developed, and that the scope of the terms TDD, TDD communication links, protocols, and nodes is intended to a priori include all such new technologies.

[0211] The terms "to prepare," "prepared," "include," "contained," and "possess," as well as their cognates, all mean "to include, but not limited to."

[0212] The term "composed of" means "to include and be limited to."

[0213] The term “essentially composed of” means that the composition, method, or structure may include additional components, steps, and / or parts, but only if the additional components, steps, and / or parts do not substantially alter the fundamental new characteristics of the claimed composition, method, or structure.

[0214] In this specification, the singular forms “a” and “an” and “the” include multiple references unless otherwise explicitly indicated by the context. For example, the term “one compound” or “at least one compound” may include multiple compounds, including mixtures thereof.

[0215] Throughout this application, various embodiments of the invention may be presented in range form. It should be understood that range form descriptions are merely for convenience and conciseness and should not be interpreted as immutable limitations on the scope of the invention. Therefore, range descriptions should be considered to clearly disclose all possible partial ranges and the individual numbers within those ranges. For example, a range description such as 1 to 6 should be considered to specifically disclose partial ranges such as 1 to 3, 1 to 4, 1 to 6, 2 to 4, 2 to 6, 3 to 6, and the individual numbers within those ranges, such as 1, 2, 3, 4, 6, and 6. This applies regardless of the size of the range.

[0216] Whenever a numerical range is shown herein, it is intended to include any cited digit (fractional or integer) within the indicated range. The expressions "across / a range between the first indicated number and the second indicated number" and "across / a range from the first indicated number to the second indicated number" are used synonymously herein and are intended to include the first and second indicated numbers and all fractional and integer digits between them.

[0217] For clarity in relation to separate embodiments, it is understood that certain features of the invention described may also be provided in combination in a single embodiment. Conversely, for brevity in relation to a single embodiment, various features of the invention described may also be provided individually, in any suitable partial combination, or as suitable in any other described embodiment of the invention. Certain features described in relation to various embodiments should not be considered essential features of those embodiments unless those embodiments are inoperable without those elements.

[0218] Although the invention has been described with regard to its specific embodiments, it is evident that numerous alternative forms, modifications, and variations will be apparent to those skilled in the art. Therefore, the invention is intended to encompass all such alternative forms, modifications, and variations that fall within the spirit and scope of the appended claims.

[0219] All publications, patents, and patent applications referenced herein are incorporated herein in whole by reference to the same extent as if each individual publication, patent, or patent application were specifically and individually indicated as being incorporated herein by reference. In addition, any citation or identification of references in this application shall not be construed as an acknowledgment that such references are available as prior art of the present invention. Section headings, to the extent in which they are used, should not necessarily be construed as limiting.

Claims

1. A method for disconnecting a wireless time-division duplex communication link, wherein the time-division duplex communication link is between a first node and a second node transmitting during time slots assigned to the first node, the second node transmitting during separate time slots assigned to the second node, and the first node transmitting in each of a plurality of frequency bands during each of the time slots assigned to the first node, and the method is The steps include further dividing the time slot assigned to the first node into continuous time intervals, Interrupting communication between the first node and the second node by transmitting each of the interfering signals using a transmitter for at least some of the time intervals, while maintaining a frequency difference between any pair of consecutive interfering signals below a frequency difference threshold, wherein each of the interfering signals is transmitted in one frequency band selected from a group of frequency bands, the group of frequency bands comprises the plurality of frequency bands, the interfering signals are transmitted in different frequency bands over at least two of the time intervals, and the frequency difference threshold does not exceed a portion of the frequency gap between (a) the lowest frequency band of the plurality of frequency bands and (b) the highest frequency band of the plurality of frequency bands. Includes, The continuous time interval includes a first group of continuous time intervals and a second group of continuous time intervals. The interruption step includes transmitting a first set of interference signals in ascending frequency bands during a continuous time interval of the first group, and transmitting a second set of interference signals in descending frequency bands during a continuous time interval of the second group. A method wherein, for at least some of the ascending frequency bands, the frequency band lies between a pair of consecutive descending frequency bands.

2. The method according to claim 1, wherein the portion thereof does not exceed the value obtained by dividing 2 by the number of frequency bands among the multiple frequency bands.

3. The method according to claim 1, wherein the portion thereof does not exceed the value obtained by dividing 4 by the number of frequency bands among the multiple frequency bands.

4. The method according to claim 1, wherein each of the ascending frequency bands is different from each of the descending frequency bands.

5. The method according to claim 1, wherein the ordered list of ascending frequency bands and the reverse-ordered list of descending frequency bands form an alternating sequence of frequency bands in which one ascending frequency band lies between a pair of consecutive descending frequency bands, or one descending frequency band lies between a pair of consecutive ascending frequency bands, and the ordered list is ordered according to the transmission time.

6. The method according to claim 1, wherein the continuous interference signal of the first set represents a frequency gap that is not less than twice the frequency gap between the continuous frequencies among the plurality of frequency bands.

7. The method according to claim 1, wherein the ascending ordered list of frequency bands includes a subset of continuous frequency bands among the plurality of frequency bands, the continuous subset being spaced by a frequency gap not less than twice the frequency gap between the continuous frequencies among the plurality of frequency bands.

8. The method according to claim 1, wherein the continuous time interval includes one or more additional time intervals in addition to the continuous time intervals of the first group and the continuous time intervals of the second group.

9. The method according to claim 8, wherein the interruption step includes transmitting an interruption signal in some or more of the ascending frequency bands during the additional time interval.

10. The method according to claim 8, wherein the interruption step includes transmitting an interruption signal in some or more of the descending frequency bands during the additional time interval.

11. The method according to claim 8, wherein the interruption step includes transmitting one or more interruption signals in one or more frequency bands that do not belong to the ascending frequency bands and the descending frequency bands during the additional time interval.

12. The method according to claim 1, wherein the frequency gap between consecutive ascending frequency gaps of each pair is equal to the frequency gap between consecutive descending frequency bands of each pair.

13. The method according to claim 1, wherein the continuous time interval of the first group precedes the continuous time interval of the second group.

14. The method according to claim 1, wherein a continuous time interval of the first group follows a continuous time interval of the second group.

15. The method according to claim 1, wherein the descending ordered list of frequency bands includes a subset of continuous frequency bands among the plurality of frequency bands, the continuous subset being spaced by a frequency gap not less than twice the frequency gap between the continuous frequencies among the plurality of frequency bands.

16. The method according to claim 1, wherein the second set of continuous interference signals exhibits a frequency gap that is not less than twice the frequency gap between continuous frequencies among the plurality of frequency bands.

17. The method according to claim 1, comprising the step of randomly selecting at least some of the transmission bands from the plurality of frequency bands.

18. The method according to claim 1, comprising the step of randomly selecting at least some of the transmission bands from the plurality of frequency bands, while imposing a predefined scope condition on the frequency bands between the time slots.

19. The method according to claim 1, further comprising the step of deviating from a predefined transmission scheme following the occurrence of an event.

20. The method according to claim 19, wherein the event is synchronized with a transmission between the first node and the second node.

21. The method according to claim 19, wherein the event includes locking onto a signal exchanged over a communication link.

22. The method according to claim 1, wherein the group includes the plurality of frequency bands and at least one additional frequency band.

23. The method according to claim 1, wherein the group includes only the plurality of frequency bands.

24. The method according to claim 1, comprising the steps of deciding to use a frequency band of another group, and interrupting communication between the first node and the second node that use a frequency band of another group.

25. The method of claim 24, wherein the use of the other group of frequency bands includes interrupting communication between the first node and the second node by transmitting each of the interfering signals for at least some of the time intervals using a transmitter, while maintaining a frequency difference between any pair of continuous interfering signals below a frequency difference threshold, and each of the interfering signals is transmitted in one frequency band selected from the other group of frequency bands, the other group of frequency bands comprising the plurality of frequency bands.

26. The method according to claim 25, further comprising the step of deciding to use the frequency bands of the other group in response to the occurrence of an event.

27. The method according to claim 25, further comprising the step of determining to use the frequency bands of the other group based on a predefined schedule.

28. The method according to claim 25, comprising the step of alternating between a plurality of groups of frequency bands.

29. The method according to claim 1, comprising the step of determining at least one property of at least some of the interference signals based on an event.

30. The method according to claim 29, wherein at least some of the properties are frequencies.

31. The method according to claim 29, wherein the event includes receiving instructions to be sent via the communication link with respect to at least one property of a future transmission via the communication link.

32. The method according to claim 31, wherein the event includes receiving a command sent via the communication link.

33. The method according to claim 31, wherein the event includes receiving information transmitted via the communication link.

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