US20200052992A1 - Systems and methods for lte-u detection - Google Patents

Abstract

A method for detecting aggressive signal transmission signatures in a wireless communication network is provided. The network includes at least one station, at least one access point, and at least one non-cooperative transmission source. The method includes steps of generating a matrix of each instance of request-to-send (RTS) messages received by the access point during a specified observation cycle, recording, in a memory of the access point, a number of cumulative RTS messages received from the station, calculating a cumulative distribution function (CDF), based on the recorded RTS message instances in the memory, for a probability of the presence of an aggressive transmission signal by the non-cooperative transmission source within a transmission range of the access point, and determining the presence of the aggressive transmission signal based on the calculated CDF being greater than a predetermined threshold.

Description

CROSS REFERENCE TO RELATED APPLICATIONS
• This application is a continuation of U.S. patent application Ser. No. 15/465,208, filed Mar. 21, 2017, which application is a continuation-in-part of U.S. patent application Ser. No. 15/439,814, which prior Application claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 62/298,037, filed Feb. 22, 2016, and to U.S. Provisional Patent Application Ser. No. 62/307,199, filed Mar. 11, 2016, all of which are incorporated herein by reference in their entirety. Application Ser. No. 15/465,208 also claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 62/311,215, filed Mar. 21, 2016, and to U.S. Provisional Patent Application Ser. No. 62/351,419, filed Jun. 17, 2016, both of which are also incorporated herein by reference in their entirety.
BACKGROUND
• The field of the disclosure relates generally to management of shared wireless communications, and more particularly, to wireless communication management utilizing aggressive signal signature detection.
• Conventional wireless communication systems may utilize unlicensed shared spectra. For example, the 2.4 GHz, 3.5 and 5 GHz frequency bands could be used for Wi-Fi, Bluetooth, Zigbee, and a range of other consumer, industrial, and medical wireless technologies. Other technology platforms also share a spectrum in other frequency ranges, and available wireless spectra will become more intensively shared as demand for wireless technologies increases. In some instances, the licensed spectra are strictly licensed to specified access technologies, and are not generally used by other access technologies within the same licensed spectrum.
• Some conventional shared unlicensed spectrum technology systems utilize algorithm- and sensing-based distributed access, which enable common use of a wireless resource, despite a lack of active coordination among users. For example, typical Wi-Fi systems employ a carrier sense multiple access with collision avoidance (CSMA/CA) network multiple access method, which is also known as “listen-before-talk” (LBT), in which carrier sensing is used, but nodes attempt to avoid collisions by transmitting only when the channel is sensed to be idle (i.e., not being used). Wi-Fi devices employ a common, standards-based protocol to avoid interference among themselves and other users, which provides a substantially equal probability of access across all users in channel conditions.
• However, new technologies are being introduced into the shared spectrum, which do not employ the cooperative techniques used by Wi-Fi devices. In particular, the introduction of mobile technologies utilizing Long Term Evolution (LTE) are known to interfere with existing technologies like Wi-Fi, when operating in the same unlicensed spectra and same geographical location, due to the centralized architecture of LTE and mobile systems where spectrum access is scheduled by the core network, instead of being coordinated with other access technologies accessing the same spectra resources. Mobile technologies utilizing LTE may dominate the access to a shared unlicensed spectrum without regard to other wireless access technologies. These non-cooperative mobile technologies can be implemented in an aggressive manner that utilizes a disproportionate share of airtime, as compared with cooperative technologies. For example, when a scheduled technology, such as LTE, competes with a technology that employs distributed coordination techniques, such as Wi-Fi, the Wi-Fi system will inherently defer to (that is, fail to transmit) the scheduled technology. In other words, the Wi-Fi system (and similar cooperative technologies) will “hear” the LTE system (or non-cooperative technologies) “talking,” and will wait their turn to access and transmit to the network. Ultimately this type of behavior will drive to an asymmetrical usage of the target spectrum resources, the LTE access technology becoming a dominant user of the spectrum under discussion.
• Wi-Fi and other cooperative/distributed technologies are thus at an inherent disadvantage in the shared spectrum, and will experience significant interference, degraded performance, and user experience when forced to compete with non-cooperative technologies as compared with when co-existing with other 802.11 access nodes. Hardware changes to Wi-Fi devices and access points (APs) have been proposed as embedded solutions to detect the non-cooperative (aggressor) signals, but such hardware changes are expensive, and would exclude existing Wi-Fi devices since retro-fitting existing 802.11 nodes is prohibitive in operation.
BRIEF SUMMARY
• In an embodiment, a method for detecting aggressive signal transmission signatures in a wireless communication network is provided. The network includes at least one station, at least one access point, and at least one non-cooperative transmission source. The method includes steps of generating a matrix of each instance of request-to-send (RTS) messages received by the at least one access point during a specified observation cycle, recording, in a memory of the at least one access point, a number of cumulative RTS messages received from the at least one station, calculating a cumulative distribution function (CDF), based on the recorded RTS message instances in the memory, for a probability of the presence of an aggressive transmission signal by the at least one non-cooperative transmission source within a transmission range of the at least one access point, and determining the presence of the aggressive transmission signal based on the calculated CDF being greater than a predetermined threshold.
• In an embodiment, a method for detecting aggressive signal transmission signatures in a wireless communication network is provided. The network includes a plurality of stations, a plurality of access points, and at least one non-cooperative transmission source. The method includes steps of transmitting a first cooperative transmission signal from a first one of the plurality of access points to a selected one of the plurality of stations, issuing a carrier sense clear channel assessment, by a second one of the plurality of access points, to one or more of the plurality of stations and of the plurality of access points, completing the transmission of the first cooperative transmission signal upon commencement of an aggressive transmission by the at least one non-cooperative transmission source, sending, from the second one of the plurality of access points, a clear-to-send (CTS) message to one or more of the plurality of stations and of the plurality of access points, detecting, by the second one of the plurality of access points, energy of the aggressive transmission, and determining, by the second one of the plurality of access points, the presence of the aggressive transmission based on the detected energy.
• In an embodiment, a wireless communications system includes a first access point including a memory, a processor, and a transceiver, and configured to wirelessly send and receive cooperative transmission data, a first electronic station configured to wirelessly communicate with the first access point and process the cooperative transmission data, and at least one electronic aggressor transmission source configured to wirelessly send and receive aggressive transmission data within a transmission range of the first access point. The transceiver is configured to receive request-to-send (RTS) messages from the first electronic station at a selected cadence for a specified observation cycle. The access point is configured to record the received RTS messages in the memory. The processor is configured to determine a transmission signature of aggressive transmission data based at least in part on a cumulative distribution function (CDF) of the stored RTS messages in the memory.
BRIEF DESCRIPTION OF THE DRAWINGS
• These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
• FIG. 1 is a schematic illustration of an operation of co-existent wireless access systems in the same unlicensed spectrum, according to an embodiment.
• FIG. 2 illustrates an exemplary transmission effect between the aggressive co-existing transmission signal and the Wi-Fi transmission of the system depicted inFIG. 1.
• FIG. 3 is a flow chart diagram of an exemplary adaptive process for detecting an aggressive signal.
• FIG. 4 is a flow chart diagram of an alternative adaptive process for detecting an aggressive signal.
• FIG. 5 is a schematic illustration of an alternative operation of co-existent wireless access systems within an unlicensed spectrum.
• FIG. 6 is a flow chart diagram of a process for detecting an aggressive signal.
• FIG. 7 is a flow chart diagram of an alternative process for detecting an aggressive signal.
• FIG. 8 is a flow chart diagram of another alternative process for detecting an aggressive signal.
• Unless otherwise indicated, the drawings provided herein are meant to illustrate features of embodiments of this disclosure. These features are believed to be applicable in a wide variety of systems including one or more embodiments of this disclosure. As such, the drawings are not meant to include all conventional features known by those of ordinary skill in the art to be required for the practice of the embodiments disclosed herein.
DETAILED DESCRIPTION
• In the following specification and claims, reference will be made to a number of terms, which shall be defined to have the following meanings.
• The singular forms “a,” “an,” and “the” include plural references unless the context clearly dictates otherwise.
• “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.
• Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about,” “approximately,” and “substantially,” are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined and/or interchanged; such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise.
• The following description features processes and systems for utilizing existing wireless transceiver technology to detect the presence of a duty-cycled LTE signal, which may be customized, transmitted within the same unlicensed band and geographical location as an 802.11 AP accessible by a wireless transceiver, which may include a CSMA/CA access system. The present embodiments relate to management of wireless communications employing different access protocols operating in the same overlapping coverage area, as well as the management of 802.11 type wireless communications when operating in an overlapping service area with an LTE-U access system.
• The embodiments herein describe and illustrate a transceiver and methods for adaptive management of co-existent wireless communications, and particularly wireless communications in the unlicensed spectrum, or unlicensed bands (e.g., 2.4 GHz, 3.5 GHz, 5 GHz, etc.). For purposes of this discussion, the term “co-existent” refers to different wireless access systems re-using the same spectral resources in the same geographical location. The different wireless access systems though, are not necessarily cooperative by nature. Examples of technologies used in the unlicensed spectrum include Wi-Fi, Bluetooth, Zigbee, with Wi-Fi (i.e., 802.11/a/b/g/n/ac/ax/ad and other 802.11 variants) presently being the dominant technology for unlicensed shared access. Wi-Fi is a LBT technology that uses CSMA/CA to optimize the efficiency of distributed access across otherwise asynchronous access transceivers. Such cooperative technology includes coexistence features that allow it to first verify the availability of the media (e.g., by LBT), before accessing a channel, that the channel is clear prior to transmission of data. CSMA/CA then allows for the management of access control to all asynchronous users (i.e., user devices) on that channel.
• Mobile technologies such as LTE are synchronous access technologies, operating in the unlicensed spectrum (e.g., LTE-U) in a non-cooperative (e.g. using a non-compliant LBT algorithm with 802.11 type systems) manner as compared with other access technologies that cannot synchronize to the LTE radio access network (RAN). LTE-U has been widely deployed, and functions to dominate the unlicensed spectrum through a centralized control of aggressive transmission techniques. The cooperative LBT based technologies are colloquially referred to as “polite” technologies, whereas the non-cooperative technologies (including LTE and LAA) are colloquially referred to as “aggressive” technologies. LTE-U is considered aggressive, since it schedules and applies traffic to the accessed channel without first assessing if the channel is clear of other network transmissions. In some LTE-U implementations, listening techniques may be employed before the LTE-U transmits, however, such techniques are not compliant with existing Wi-Fi LBT algorithms. LTE-U may sometimes implement additional features to co-exist with other LTE-U RAN transmissions, but LTE-U will typically take over the channel when co-existing with 802.11 access technologies for more than 50% of the time without such separate systems.
• LTE-U generally operates according to an ON/OFF duty cycle. In some instances, the LTE-U duty cycle is static, that is, of substantially constant duration. In other instances though, the duty cycle could be variable. Additionally, more than one aggressive LTE-U signal may be present within the transmission/reception region and spectrum of a polite co-existent access technology The embodiments disclosed herein therefore, feature protocols and methods for aggressive signal detection in shared spectrum resources (or aggregate channels) for both static and variable duty cycles. The disclosed systems and methods are configured to adapt their use of the shared spectrum to enable more efficient access in the presence of non-cooperative technologies. These features thus optimize the operation of 802.11 and other cooperative technologies when co-existing with LTE technologies in unlicensed spectra.
• In an exemplary embodiment, existing polite technologies in the unlicensed band are configured to mitigate the transmission from aggressive technologies that are not designed for coexisting with other asynchronous access technologies like 802.11. Such mitigation techniques further configured to operate in their normal manner when in the presence of other polite protocols, but adapt their operation in the presence of aggressive protocols. For simplicity of explanation, many of the following examples are described only with respect to Wi-Fi as the polite protocol and LTE-U as the aggressive protocol. Nevertheless, the systems and methods described herein may also be utilized similarly with respect to other polite and aggressive technologies, respectively.
• According to an embodiment, a cooperative technology, such as Wi-Fi, is configured to monitor and/or sense the spectrum for which access is desired, and detect the specific waveforms (also known as “signatures”) of non-cooperative technologies, such as LTE. In some examples, the cooperative technology of the present systems and methods are configured to utilize existing IEEE 802.11 wireless networking protocols such as Request to Send (RTS)/Clear to Send (CTS) to detect the presence of a non-cooperative technology signal. In this example, when an aggressive signal is not detected, the cooperative technology can be configured to remain in its legacy state of distributed access protocols. That is, the cooperative technology will respond without changing affecting the functionality and performance of the 802.11 access technology, such as the LBT protocol, for example. However, when an aggressive, non-cooperative technology is detected, the transceiver of the cooperative technology may be further configured to adapt and optimize its performance to wait for the aggressive signal to stop transmitting, avoid the aggressive signal, adjust one or more of the power, throughput, and reliability of the cooperative signal to overcome the aggressive signal, or more generally coexist with the aggressor technology.
• As described herein, the phrase “user equipment” includes an electronic device or system utilizing an aggressive, non-cooperative technology protocol, such as LTE-U. The phrase “Wi-Fi device” includes an electronic device, such as a station or STA, that has the capability to use one of the existing 802.11 protocols. For example, a Wi-Fi device can include, without limitation, one or more of a laptop, a desktop personal computer (PC), personal digital assistant (PDA), AP, and a Wi-Fi phone/smartphone. The Wi-Fi device may be fixed, mobile, or portable, and includes a transceiver or transmitter/receiver combination, an 802.11-conformant media access control (MAC) and physical layer (PHY) interface to a wireless medium (WM).
• In the exemplary embodiment, each of the foregoing adaptation techniques may be implemented alone, or in combination with one or more of the other techniques. In some embodiments, the several techniques may be implemented simultaneously, or in succession. In this example, a transceiver or node utilizing cooperative technology is configured to a particular channel of the shared spectrum and to adapt its medium access cooperative protocol in order to maintain its performance in the presence of non-cooperative technologies in the same shared spectrum. These advantageous adaptation techniques are described further below with respect to several drawings.
• FIG. 1 is a schematic illustration of an exemplary shared spectrum system100, according to an embodiment. System100 includes at least one user equipment (UE)102, a Wi-Fi device/Wi-Fi station104, a node106, and an access point (AP)108. User equipment102 may be, for example, a mobile handset, or similar device, that implements an LTE-U transmission protocol to establish an LTE transmission110 with node106. In the exemplary embodiment, node106 may be, for example, an E-UTRAN Node B, also known as Evolved Node B, (abbreviated as eNodeB or eNB) as a hardware element that is communicatively coupled with a mobile phone network (not shown) that communicates wirelessly with user equipment102. In some embodiments, node106 may further include a base transceiver station (BTS) for a Global System for Mobile communication (GSM) network. In the exemplary embodiment, Wi-Fi device104 includes a transceiver or cooperative node (not shown), which establishes a Wi-Fi transmission112 with access point108. In an embodiment, the cooperative node of Wi-Fi device104 includes the transceiver.
• In operation, user equipment102 generates anaggressive transmission signal114 according to a duty cycle (symbolically represented by dashed lines) within the range of Wi-Fi device104, which creates an interference116 in Wi-Fi transmission112. In the exemplary embodiment, Wi-Fi transmission112 implements a polite LBT protocol that will typically give way to the detected presence ofaggressive transmission signal114. That is, a cooperative shared spectrum technology, such as Wi-Fi, has the ability to “listen” to the channel of the unlicensed shared spectrum to determine the presence of other users. This listening ability is conventionally employed only for the specific purpose outlined in distributed access protocols for coexistence with other cooperative technologies.FIG. 1 is illustrated schematically, and is not intended to represent the actual scale or proximity of the several elements depicted therein. For example, in practical operation, node106 may operate at significantly higher power levels than user equipment102, and thereby be a more significant factor to creating interference116, and thusFIG. 1 is equally instructive with the respective positions of user equipment102 and node106 interchanged. The principles described herein are applicable to either scenario. In an exemplary embodiment, AP108 is within the proximity of interference116.
• In an embodiment, Wi-Fi device104 is further configured to utilize its existing listening capability to monitor system100, and then detect and identify the presence ofaggressive transmission signal114. In an example of the operational environment of system100, Wi-Fi device104 operates proximate to, that is, side-by-side with, one or more cells of user equipment102. In other words, Wi-Fi device104 operates according to the 802.11 protocol, and each cell of user equipment102 is capable of processing its own LTE-U download and upload traffic (e.g., transmission110 spread. However, since the LTE-U traffic can be transmitted simultaneously with the Wi-Fi traffic (e.g., transmission112) under some conditions, Wi-Fi device104 will perceive the received LTE-U traffic as interference (e.g., interference116), which will degrade the performance of the received Wi-Fi traffic, by either or both of Wi-Fi device104 and access point108.
• According to the embodiments herein though, either or both of Wi-Fi device104 and access point108 are advantageously configured to implement existing technology to detect and process the aggressor LTE-U traffic (e.g., aggressive transmission signal114) through a novel implementation of the RTS/CTS protocol and the PHY interface. In an exemplary embodiment, Wi-Fi device104 is configured to cooperate with access point108 to detect the signature of an aggressive transmission, such as an LTE-U signal, by registering the receipt of individual CTS frames in the PHY layer/interface. As discussed further below, these operational principles can also be applied in the reverse, utilizing the PHY layer of access point108, and also by registering receipt of individual RTS frames. Once the signature of an aggressive transmission (e.g., aggressive transmission signal114) is detected, Wi-Fi device104 is additionally configured to adapt the number of RTS frames transmitted to and received by access point108 for processing. By adapting the number of RTS frames transmitted and or processed in the presence of an aggressive transmission signal, the present systems and methods are advantageously able to optimize the user throughput and related traffic latency over conventional techniques.
• FIG. 2 illustrates anexemplary transmission effect200 betweenaggressive transmission signal114 and Wi-Fi transmission112 of system100,FIG. 1.Transmission effect200 is further considered against a typical LTE signal202 (e.g., from node106,FIG. 1). In the example illustrated inFIG. 2,LTE signal202 is similar to aggressive transmission signal114 (e.g., LTE-U signal), except thataggressive transmission signal114 operates according to a duty cycle, whereasLTE signal202 does not. For the purposes of this discussion, the lack of duty cycle toLTE signal202 is not a consideration becauseLTE signal202 is not intended for operating in the unlicensed Wi-Fi spectrum band.
• According to the embodiment depicted inFIG. 2,aggressive transmission signal114 utilizes an LTE-U duty cycle204 and an LTE-U waveform206 (e.g., from node106,FIG. 1). Wi-Fi transmission112 includes a periodic cadence of CTS frames208 and RTS frames210 between Wi-Fi device104 and access point108. For purposes of this discussion, CTS frames208 and RTS frames210 are described as being transmitted from and received by access point108, respectively. Nevertheless, the principles described herein are equally operable considering CTS frames208 being received by Wi-Fi device104, and RTS frames210 being transmitted therefrom.
• In an exemplary operation, a wireless transceiver (not shown) of Wi-Fi device104 (FIG. 1) transmits a CTS message, for eachCTS frame208, according to IEEE 802.11 standards. In this example, the CTS message may include, without limitation, the following attributes: (i) a destination address, which is the MAC address of the transceiver; and (ii) a duration, which is a maximum duration assigned as a predetermined value and a periodicity T. Once received and processed, the CTS message functions to silence surrounding Wi-Fi transceivers for the duration of, and the transceiver of Wi-Fi device104 is able to capture the channel energy activity for duration T. Data for this captured channel energy activity may then be stored in a memory (not shown) of Wi-Fi device104, and then combined with previous captured data in the memory, if any. At the end of the capture duration/periodicity T, if the accumulative duration has not exceeded a pre-specified observation period S, expected to be the ON LTE-U cycle duration, the transceiver of Wi-Fi device104 transmits another CTS frame and repeats the process described immediately above, with the same periodicity.
• Once the value of the capture duration T is greater than the specified observation period S (e.g., 160 ms), the AP or station will no longer be able to receive the CTS signals due to the ongoing LTE traffic, a processor (also not shown) of Wi-Fi device104 (or access point108) is configured to perform an analysis of the captured RTS or CTS data. In this analysis phase, the processor is configured to compare the measured received power of the captured RTS or CTS data to a predefined threshold. If this predefined threshold has been reached or exceeded, the processor determines that no duty-cycled LTE has been detected. That is, the processor makes a determination that Wi-Fi device104 is not in the presence of an aggressor transmission signal. In an exemplary embodiment, once the determination has been made that in aggressive, non-cooperative signal is not interfering with the Wi-Fi transmission, the analysis process may and, and relevant detection data stored in the memory may be discarded. If, however, the predefined threshold has been reached, in some embodiments, the processor is configured to perform further analysis of the captured data to compare the captured data to pulse characteristics of the duty-cycled LTE (e.g., LTE-U duty cycle204). In an embodiment, due to the characteristics of the dynamic propagation environment, it may reception of RTS signals (assuming that the LTE-U is in operation during such time interval) may be inhibited or prevented. In such circumstances, statistical processing over a longer period of time (e.g., longer than the duty cycle of the LTE-U system) is advantageous.
• More particularly, the comparison of the captured data may be performed with consideration of the ON portion ofduty cycle204 during the observation period S. If a portion of the observation period S overlaps the ON portion ofduty cycle204, the captured data would include received RTS or CTS signals (in consideration of whether the respective 802.11 node is an AP or a station). In this example, when the reception of the RTS or CTS signals is periodically discontinued with for a period of time which is multiple of 10 ms, then the processor utilizes the protocol to decide whether the respective 802.11 node (either AP or station) is subject to an aggressor LTE-U waveform206 either in the ON or OFF state. When the observation period S is greater than the ON portion ofduty cycle204, the entire duration of the ON portion may be indicated within the captured data. Under either circumstance, a correlation between the captured data and the duty-cycled LTE is established from processing the captured data. In at least one embodiment, when the observation period S is greater than the duration of the ON portion ofduty cycle204, the results from a comparison algorithm are further transmitted to a centralized system processor (not shown) for comparison with the captured data relating to the duration of the ON portion received by the same 802.11 node, but based on the reception of RTS or CTS signals received from other surrounding Wi-Fi nodes within a predetermined vicinity of Wi-Fi device104. Such additional data from other Wi-Fi devices may be used by Wi-Fi device104 and/or access point108 to further validate the probability that interference (e.g., interference116,FIG. 1) in Wi-Fi transmission112 is caused byaggressive transmission signal114.
• Referring back toFIG. 2, in the exemplary embodiment, RTS frames210 are transmitted (e.g., by AP108,FIG. 1) during the presumed aggressor transmission activity, with a cadency of 10 milliseconds (ms), for a capture duration T of 40*k ms, where k is an integer equaling 1, 2, 4, 6, 8, etc. According to this exemplary embodiment, a carrier-sensing adaptive transmission (CSAT) cycle of T=40 ms, employed by the LTE-U aggressor system, is targeted. Nevertheless, the operational principles described herein are fully applicable to algorithms applying a duration T equaling 20, 80, 160, or 360 ms, or multiples thereof. Once anRTS frame210 is so received, a serviced station (e.g., Wi-Fi device104) of the system (e.g., system100,FIG. 1) is configured to respond with anappropriate CTS frame208.
• In the alternative embodiment, RTS frames210 are transmitted every 10 ms (e.g., by Wi-Fi device104,FIG. 1), and without losing generality, for RTS frames210 having periodic detection intervals (i.e., periods between frames) of 5 ms, 10 ms, 20 ms, 40 ms, or 80 ms. In this alternative embodiment, the particular 802.11 node (e.g., AP108,FIG. 1) receiving the transmitted RTS frame(s)210 is configured to respond with anappropriate CTS frame208.
• If ongoing aggressor LTE-U activity is present, CTS frames208 will only be received during the LTE-OFF portion ofduty cycle204, the servicing AP (e.g., access point108) is generally expected to decodeCTS frames208 for only half ofduty cycle204. Accordingly, the application processor (disposed within Wi-Fi device104 and/or access point108, for example) is configured to make a determination of the presence of an aggressive transmission signal based on the number of CTS frames received within a predetermined time period. In some embodiments, where neighboring random traffic is present, processing of the LTE-U envelope may utilize averaging algorithms. Whereduty cycle204 static/consistent, the occurrence of the LTE-OFF portion can then be easily predicted, and the target STA/AP will suppress the reception of unnecessary CTS frames212 that occur during the LTE-ON portion ofduty cycle204, which will not generate a corresponding PS frame/message in response thereto while the LTE signal is ON. By predicting duration of the of the LTE-ON portion, additional power can be saved by suppressing the generation of unneeded RTS frames.
• Referring again toFIG. 2, in an exemplary embodiment, the PHY Register is implemented to register instances of received CTS frames208. In this exemplary embodiment, one station (Wi-Fi device) is discussed with respect to one AP. Nevertheless, a person of ordinary skill in the art will appreciate the applicability of the principles described herein for a plurality of stations/devices within the vicinity of an AP (discussed further below). In this example, an LTE-U signal has a cycle of 40 ms, and an 0xFF PHY Register has 8 bits written in accordance with a reference clock signal CLK of 10 ms and covering a total observed duration of 80 ms (i.e., two times the expected LTE-U cycle). Register 0xFF is used by the LMAC/PHY layers of the receiving 802.11 node to read/write the detected RTS or CTS detection information (i.e., register CTS occurrences), and this process of operation is also applicable for CSAT=20 ms (e.g., for an RTS periodicity of 2.5 ms). A CSAT cycle of 80 ms, for example, could require a 16-bit register, for RTS periodicity of 10 ms. Other embodiments may use a variety of PHY register sizes (8, 16, 32 bits, etc.) for different RTS periodicities targeting various LTE cycle ON or OFF durations.
• In an exemplary operation, a logical masking procedure is further implemented to produce particular resultant digital outcomes. For example, for a logical result of 00 (hexadecimal), the processor will determine that there is no aggressive LTE-U operation occurring. For a logical result of 0F, F0 (also hexadecimal) or x1111y (for an 8-bit packet), the processor determines that an aggressive LTE-U operation is detected.
• In an alternative embodiment, a PHY Register 0xFFFF having 16 bit is implemented to register the instances of received RTS or CTS frames208. In this alternative embodiment, 0xFFFF PHY Register is written in accordance with CLK=10 ms, for a total duration of CTS transmission of 160 ms and is used by the LMAC/PHY layers to read/write the CTS detection information from STA(i), where i is an integer from 1 to N, indicating that the capability of the algorithm is increased to i stations. From the RTS or CTS detection information, a cumulative distribution function (CDF) of a variable X(i), where X(i) represents a string length of consecutive “1”s detected by the receiving AP or station and captured accordingly in the STA(i) register; this string can be employed for determining the probability of an occurrence of an aggressive LTE-U signal. From this information, a matrix of size N×16 can be constructed to reflect the CTS frames received from the N Wi-Fi devices104.
• In operation of the alternative embodiment, probabilities P1 (X(i)=4) and/or P2 (X(i)=8) are calculated, as well as CDF(P1) and/or CDF(P2). In the case where CDF(P1) or CDF(P2)>m (where m=a predetermined probability of an LTE duty cycle occurrence, e.g. m=0.8), then the processor of a target AP (e.g., access point108,FIG. 1) determines the presence of an interference (e.g., interference116,FIG. 1) generated by an LTE-U Node (e.g., node106,FIG. 1). The operations of the exemplary and alternative embodiments are described further below with respect toFIG. 3.
• FIG. 3 is a flow chart diagram of anadaptive process300 for detecting an aggressive signal. In the exemplary embodiment, the LMAC of the AP defines the PHY register (e.g., 0xFF) to read/write the CTS detection information before the transmission of greater than or equal to X/n number of RTS signals, where X=CSAT cycle duration (20 ms, 40 ms, 80 ms, 160 ms, etc.), and where n=LTE-U duty cycle (n≤1). The PHY Register is then advantageously utilized to write therein the presence or absence of received CTS messages as a 1 or 0, respectively, expected to be received with a certain periodicity (e.g. 10 ms). In the exemplary embodiment, one such register is defined for each target station. A target matrix (e.g., 0xFFFF) can then be established to have a size k*m of binary values, where k=number of stations polled, and m=number of clock cycles (e.g., each clock cycle has a duration of 10 ms, signifying the periodicity of RTS signals transmission).
• In the exemplary embodiment,process300 is implemented at either the station level or the AP level. For instances whereprocess300 is triggered by a station transceiver, the target transmission station will wait for CTS responses from neighboring stations or access points; in another embodiment, a receiving station aware of the RTS transmissions, will detect received RTS signals for a period of time larger than S. Where the trigger comes from either a station or AP, the target AP/STA will wait for a duration T (in ms), and then a processor or the STA/AP will analyze the content of the particular 0xFF set of registers. In another embodiment, a processor of the monitoring AP/STA will analyze the content of the set of 0xFFFF registers. An amount of successfully received CTS frames/messages is then recorded as a value Y. According to the exemplary embodiment, the transceiver of the target STA/AP is configured to trigger more test cycles dependent on reaching a value greater than or equal to a target success probability (p) of the CDF function, and the processor of the target STA/AP is configured to determine the duration of the LTE-U ON portion of the duty cycle (e.g., duty cycle204) based on a calculation of X*Y/p.
• If, during the LTE-U detection cycle, an LTE-U signature is not detected during a pre-configured time-out period, the processor of the respective device is configured to increase the detection interval by a pre-defined value K. In this respect,process300 is different from the processing described above in the case of a static, regular duty cycle. As explained below in further detail,process300 is further capable of detecting and adapting to aggressor LTE-U signals having a variable duty cycle, or the presence of a plurality of different LTE-U signals capable of causing interference in Wi-Fi transmission signals.
• In an alternative embodiment,process300 is implemented at the AP level. According to the alternative embodiment, the LMAC of the AP manages the read/write register (e.g., 0xFFFF) concerning the detected RTS information resulting from the reception of number RTS frames208 greater than or equal to X, where the RTS frames208 are measured every T=10 ms for a duration of 160 ms (for an expected LTE cycle duration of 80 or 160 ms), and where X=16T, where n is the number of consecutive RTS signals/frames received (at 10 ms intervals), and where X(i) represents a maximum length of consecutive “1” or “0” binary values representing a detected or non-detected RTS, respectively, for a particular station STA(i).
• The PHY Register is then advantageously utilized to write therein the received CTS presence in register 0xFFFF as a “1.” In this alternative embodiment, one such register is also defined for each target station, and a processing matrix including binary values and having a size n*16m can then be established, where n=number of stations polled, and m=number of 160 ms cycles under test. In one embodiment m=1, therefore the underlying matrix has a size of n*16. According to this alternative, a processor of the serving AP is configured to monitor the RTS requests from neighboring stations, STA(i). The target AP (e.g., AP108,FIG. 1) will wait for 160*m (in ms), where k₁>2k, and then a processor of the target AP is configured to begin analyzing the content of the matrix.
• Similar to the exemplary embodiment, above, in the alternative embodiment the transceiver of the target AP is configured to trigger more test cycles dependent on the target success probability (p). The processor of the target AP is configured to determine the duration of the LTE-U OFF or ON portions of the duty cycle (e.g., duty cycle204) based on a calculation of the CDF of the X(i) probability distribution function P(Xi)≥p (for the threshold m). Similar to the exemplary embodiment, described above, if, during the LTE-U detection cycle of this alternative embodiment, an LTE-U signature is not detected for the time-out period, the AP processor is configured to increase the detection interval by a pre-defined value K. Once the detection interval reaches640 ms, for example, the process is terminated since the algorithm didn't detect any LTE-U aggressor.
• Process300 is described in further detail as follows. In both the exemplary and alternative embodiments,process300 begins atstep302. Atstep302,process300 starts the LTE-U detection process.Process300 then proceeds to step304, where a processor of a STA/AP initializes the detection interval to a predetermined minimum value (e.g. 20 ms). Atstep306,process300 increases the detection interval by K percent, and proceeds to step308. In one embodiment K=100%. Step308 is a decision step. Instep308,process300 determines if the total number of RTS frames transmitted is greater than the observation cycle S.
• When the total number of transmitted RTS frames is greater than the observation cycle S,process300 proceeds to step310, whereprocess300 begins its analysis subprocess, and then proceeds to step312. Instep312,process300 records the number of received consecutive CTS signals having the same value, and proceeds to step314. Instep314,process300 utilizes a processor of the STA/AP to render a determination that the signature of an LTE-U signal is detected, and also a calculation of the duration of the LTE-U-ON portion of the duty cycle according to X*Y/p, as described above.Process300 and proceeds fromstep314 to step316. Step316 is a decision step. Instep316, the processor of the target STA/AP determines whether the CDF of P1 or P2 is greater than m, as described above. If, instep316, the processor determines that the CDF of P1 or P2 is greater than m,process300 then proceeds fromstep316 to step318, whereprocess300 terminates or restarts back atstep302.
• Referring back to step308, if the total number of transmitted RTS frames is not greater than the observation cycle S,process300 instead proceeds to step320, where the RTS message is transmitted with aduration T. Process300 then moves fromstep320 to step322, where the processor of the target STA/AP waits for CTS frames from a number k of served transceivers in the neighborhood.Process300 then proceeds to step324, where a number of cumulative, non-received CTS frames are recorded as the value Y for each station STA(i) subject toprocess300.Process300 then proceeds fromstep324 to step326, where the respective transceiver of the target STA/AP waits for a period duration of X (in ms), which, in some cases, is equal to the targeted CSATduration T. Process300 then proceeds fromstep326 back todecision step308.
• Referring back todecision step316, if the CDF of P1 or P2 is not greater than m,process300 proceeds fromstep316 to step328. P1 represents the probability of detecting a max string of 4 “0” or“1” binary values for STA(i), with I=1 . . . N. P2 represents the probability of detecting a max string of 8 “0”s or “1”s. for STA(i), with i=1 . . . N. Other embodiments may use probability functions associated with strings of 16 or 32 consecutive “1” or “0”. Step328 is also a decision step. Instep328,process300 determines whether the predetermined time-out duration has been exceeded. If the predetermined time-out duration has been exceeded,process300 proceeds fromstep328 back to step306, where the detection interval is increased, andprocess300 then proceeds fromstep306 as described above. If, on the other hand, the processor determines that the predetermined time-out duration has not been exceeded,process300 proceeds fromstep328 back to step312, where a number of cumulative CTS frames is recorded, andprocess300 will then continue fromstep312.
• FIG. 4 is a flow chart diagram of an alternativeadaptive process400 for detecting an aggressive signal.Process400 is similar toprocess300, in that many of the individual steps are the same, as well as much of the sequence of events and placement of decision steps. For example, steps302,304,306,316,318, and328 ofprocess300 are substantially the same assteps402,404,406,316,418, and428 of process400 (described further below).Process400 otherwise follows a similar logical organization of processing steps.Process300 and400 differ in thatprocess300 may originate from either the station or the AP, whereasprocess400 originates from the AP.
• Process400 is described in further detail as follows. Process400 starts an LTE-U detection process atstep402, and then proceeds to step404, where a processor of an AP initializes the detection interval to a predetermined minimum value (e.g. 20 ms). Atstep406,process400 increases the detection interval by K percent, and proceeds to step408. In one embodiment K=100%. Step408 is a decision step. Instep408,process400 determines if the total number of RTS frames received is greater than the observation cycle S. When the total number of received RTS frames is greater than the observation cycle S,process400 proceeds to step410, whereprocess400 begins its cumulative RTS subprocess, and then proceeds to step412.
• Instep412,process400 records the number of cumulative CTS frames received for Y stations, and proceeds to step414. Alternatively, instep412, the number of cumulative RTS frames are recorded. Instep414,process400 utilizes a processor of the AP (e.g., access point108,FIG. 1) to calculate the duration of the LTE-U ON/OFF period to equal P(X(i)={2, 4, 8})≥m, meaning the cumulative probability distribution of receiving a string length of 2, 4 or 8 of consecutive “1” or “0” with a probability >m.Process400 then proceeds fromstep414 to step416. Step416 is a decision step. Instep416, the processor of the target AP determines whether the CDF of P1 or P2 is greater than m, as described above. If, instep416, the processor determines that the CDF of P1 or P2 is greater than m,process400 then proceeds fromstep416 to step418, whereprocess400 terminates or restarts back atstep402.
• Referring back to step408, if the total number of received RTS frames is not greater than the observation cycle S,process400 instead proceeds to step420, where the AP transceiver is configured to continue to receive an RTS message every 10 ms.Process400 then moves fromstep420 to step422, where the processor of the target AP waits for RTS frames from a number k of served stations.Process400 then proceeds to step424, where a number of non-received RTS signals are recorded (as “0”) for each station STA(i) to be recorded in the related matrix for STA(i).Process400 then proceeds fromstep424 to step426, where the transceiver of the target AP continues for 160 ms.Process400 then proceeds fromstep426 back todecision step408.
• Referring back todecision step416, if the CDF of P1 or P2 is not greater than m,process400 proceeds fromstep416 to step428. P1 again represents the probability of detecting a max string of 4 “0” or “1” binary values for STA(i), with I=1 . . . N. P2 again represents the probability of detecting a max string of 8 “0”s or “1”s. for STA(i), with i=1 . . . N. Other embodiments may use probability functions associated with strings of 16 or 32 consecutive “1” or “0”. Step428 is a decision step. Instep428,process400 determines whether the predetermined time-out duration has been exceeded. If the predetermined time-out duration has been exceeded,process400 proceeds fromstep428 back to step406, where the detection interval is increased, andprocess400 then proceeds fromstep406 as described above. If, on the other hand, the processor determines that the predetermined time-out duration has not been exceeded,process400 proceeds fromstep428 back to step412.
• Accordingly, by utilizing only existing hardware already present in existing Wi-Fi devices/stations and APs, the novel systems and methods described above thus realize significant advantages over conventional shared access systems by implementing the adaptive contention and mitigation techniques for polite, non-aggressive Wi-Fi transmissions coexisting with aggressive LTE-U transmission signals that utilize the same shared access systems. The present systems and methods are advantageously capable of detecting the signature of an aggressive LTE-U transmission utilizing only existing hardware such as the MAC and PHY layers, and existing protocols such as the LBT and IEEE 802.11. The systems and methods described herein are useful to detect the LTE-U signatures algorithms that in a simple sense count received RTS and CTS signals corresponding to a nearby aggressive transmission signal having a duty cycle, in the present systems and methods are adaptable for both a static duty cycle as well as a variable cycle for one or more such aggressive signals
• In some embodiments, RTS/CTS transmission reception can be dynamically altered according to the presence of one or more aggressive transmission signals, by increasing or decreasing the frequency of RTS signals. Through the algorithms implementing the RTS or CTS counts the processors of the stations/access points, reliable estimates of the existence of an LTE-U or the like the predicted with increasing accuracy, and the duration of both the LTE ON and LTE OFF state transmissions may be determined for both static and variable duty cycles and without requiring any embedded hardware added to a Wi-Fi device to directly detect an LTE-U transmission signal, as would node106,FIG. 1, for example.
• In some of the embodiments described above, the Wi-Fi device (e.g., Wi-Fi device104,FIG. 1) is further configured to reduce MAC layer frame sizes to increase successful reception of the transmitted Wi-Fi signal. By determining the time when the periodic LTE-U transmissions are off (LTE OFF), the Wi-Fi device is capable of adjusting the MAC layer frame size to optimally occur within the period of the LTE OFF state, and thereby increase the probability of collision-free Wi-Fi transmissions.
• According to the advantageous systems and methods disclosed herein, a Wi-Fi device, node, or transceiver is capable of realizing adaptation techniques for shared channel access models and mechanisms based upon the detection of aggressive technology signatures on the shared spectrum. Algorithms to implement any or all the above described processes may be implemented within an application processor, a MAC co-processor, or the Upper MAC (UMAC)/Lower MAC (LMAC) layers of supporting architecture of a station and/or AP, although the LTE-U correlation subprocesses will be more typically executed by an application processor on the AP side. A particular advantage though, of such implementations derives from the availability of the PHY layer being used in a non-conventional manner, in addition to the ability to avoid having to make any PHY changes or updates on either the AP or the station side.
• FIG. 5 is a schematic illustration of an alternative sharedspectrum system500, according to an embodiment.System500 includes at least one aggressive transmission source502 that transmits anaggressive transmission signal504. In this example, aggressive transmission source502 is discussed as an LTE-U source, andaggressive transmission signal504 is an LTE-U signal, but a person of ordinary skill in the art will understand, after reading and comprehending the present disclosure and drawings, thatsystem500 will also apply to other types of aggressive sources/signals, as described above.
• System500 further includes, within the transmission range ofaggressive transmission signal504, at least a first station506 and asecond station508, and a first access point510 and asecond access point512, which are described as Wi-Fi devices for the purposes of this example. In the exemplary embodiment, only two stations and access points each are illustrated for ease of explanation. A person of ordinary skill in the art will understand, in light of the present disclosure, that the principles described herein are applicable for additional stations and access points. In operation, according to an exemplary embodiment,system500 utilizes an 802.11 Carrier Sense Clear Channel Assessment (CS/CCA) to determine if LTE-U signal504 is present within the range of first and/orsecond access points510,512. That is, CS/CCA is implemented to determine if a transceiver (not shown) of the stations506,508 (e.g., a Wi-Fi device radio) is able to transmit, or if the respective transceiver should wait for the shared channel to become available.
• In further operation of the exemplary embodiment, CS/CCA can also be implemented to determine if the detected traffic is aggressive (e.g., LTE-U) or cooperative (e.g., Wi-Fi), as described above. For example, before first access point510 sends a firstcooperative transmission signal514 and/orsecond access point512 sends a secondcooperative transmission signal516, the respective AP will first implement a mechanism such as CS/CCA to determine if the channel is available. Implementation of the carrier sense mechanism will result in a detection of one of: (i) energy, along with a signal and a preamble to decode; (ii) energy only, without a signal to decode; and (iii) the channel is idle, and available for transmission. Further operations ofsystem500 are described below with respect toFIGS. 6-8, as follows.
• FIG. 6 is a flow chart diagram of aprocess600 for detecting an aggressive signal, such as LTE-U. Process600 starts atstep602, where first AP510 issues (e.g., over first cooperative transmission signal514) a CS/CCA request to the PHY layer of the radio/transceiver of first station506. Once the CS/CCA request is issued,process600 proceeds to step604. Step604 is a decision step. Atstep604,process600 analyzes the channel for detected spectrum energy. If no energy or signal is detected by a radio/transceiver of the respective AP (e.g., first AP510, second AP512),process600 proceeds to step606, where the respective radio indicates that the channel is idle, and available for Wi-Fi transmission.
• Referring back todecision step604, if the energy or signal is detected by the radio/transceiver of the respective AP,process600 proceeds to step608. Step608 is a decision step. Instep608,process600 determines if the detected energy/signal corresponds to a Wi-Fi signal. Ifprocess600 determines that the detected energy is a Wi-Fi signal,process600 proceeds to step610, whereprocess600 will decode the preamble to the Wi-Fi signal and/or detect energy in a power ratio range of approximately −82 decibel-milliwatts (dBm).Process600 then proceeds to step612, and determines that the channel is “busy” to indicate an active Wi-Fi transmission. That is, the channel is occupied by a cooperative signal, and general LBT protocols may be further implemented.
• Referring back todecision step608, ifprocess600 determines that the detected energy is not a Wi-Fi signal,process600 proceeds to step614, whereprocess600 will detect energy in a power ratio range of approximately −62 dBm and determine that there is no preamble portion to the detected energy, which together indicate that the detected energy represents a signal other than a Wi-Fi signal.Process600 then proceeds to step616, where the detected energy/signal is reassessed at regular intervals of varying durations (e.g., for AP radio status “on”) in order to identify a pattern of the detected non-Wi-Fi related energy. Once a signal pattern is so identified,process600 then proceeds to step618, where the identified pattern is aligned to varying normal duty cycles (e.g., of an LTE-U signal) to determine the ON and OFF portions of the LTE-U signal duty cycle. As discussed above, once so identified, the respective AP can schedule Wi-Fi transmissions to occur during the calculated off portion of the LTE-U duty cycle.
• FIG. 7 is a flow chart diagram of analternative process700 for detecting an aggressive signal, and with reference toFIG. 5, above.Process700 can be implemented in conjunction with, and/or as an alternative to,process600, described above. Process700 starts atstep702, where first AP510 transmits (e.g., over first cooperative transmission signal514) to first station506. Instep704,second AP512 issues (e.g., over second cooperative transmission signal516) a CS/CCA request, which results), due to the detection of firstcooperative transmission signal514, in one or more of an identification of a Wi-Fi preamble, a −82 dBm energy signal, and a backoff delay of the network allocation vector (NAV).
• Instep706, LTE-U source502 begins its aggressive transmission within the range of the respective APs. Instep708, firstcooperative transmission signal514 betweenfirst AP512 and first station506 degrades in the presence of the aggressive LTE-U signal504, andfirst AP512 completes its send.Process700 then proceeds to step710, wheresecond AP514 issues CTS to all stations and APs within its transmission range. Instep712,second AP514 issues a CS/CCA request detects resultant energy having no preamble and at −62 dBm, thus corresponding to a detection of the LTE-U signal beginning transmission instep706. Instep714,second AP514 requests radio measurements on all channels within range, in order to find an idle channel in which to transmit. In an alternative embodiment, instep714,second AP514 further issues a dynamic frequency selection (DFS)-like change to implement a spectrum-sharing mechanism allowing wireless transmissions to coexist with radar-like transmissions. Instep716, one or both of the respective APs analyzes the spectrum for the LTE-U signature or pattern based on multiple queries.
• FIG. 8 is a flow chart diagram of anotheralternative process800 for detecting an aggressive signal. In an exemplary embodiment ofalternative process800,process800 is based on an algorithm input which may be gathered using the CCA mechanism described above. Alternatively,process800 may be implemented utilizing particular code does not utilize CS/CCA mechanisms. In some embodiments, the Atheros spectral scan utility is utilized, which, for the purposes of this example, represents one possible code that produces relevant Fast Fourier Transform spectral data.Process800 is also described with respect to the embodiment illustrated inFIG. 5, above.Process800 can be implemented in conjunction with, and/or as an alternative to, either or both ofprocesses600 and700, described above.
• Process800 is implemented at the AP level, and starts atstep802. Instep802, the processor (not shown) of the respective AP analyzes power levels of all of the samples taken of the spectral data to determine the bounds of the detected Wi-Fi energy, and also the bounds of the detected interference energy (if any). In an exemplary embodiment, step802 further includes an intermediate substep of receiving an indication that a statistical CDF success threshold has been achieved (e.g.,step316,FIG. 3,step416,FIG. 4). Instep804, one or more square wave signals are created from the sample spectral data, utilizing the determine bounds calculated instep802. In step806,process800 examines all of the created square wave signals fromstep804, and determines the periodicity and duty cycle of the created square wave signals. Step808 is an optional step. Instep808,process800 discards square wave data that does not correspond to the periodicities and duty cycles calculated in step806. Step810 is also an optional step. Instep810, if the created square wave data (fromsteps804 and806) was not sufficient to generate square wave patterns having reliable periodicities and duty cycles, process803 re-analyzes the shared spectrum channel for noise, in order to determine the probability of measuring consistent square wave patterns.
• According to the advantageous systems and methods described herein, an AP may be configured to instruct stations to transmit based on the probability determination of an aggressive transmission (e.g., LTE-U) within the range of the shared spectrum. The present systems and methods are further uniquely capable of utilizing MAC messages and NAV messages from the AP to stop, or inhibit, RTS messages while the AP continues to transmit. In some embodiments, the NAV messages are a portion of the MAC messages. These MAC or NAV messages may be used to block RTS messages altogether in the presence of an aggressor source, or alternatively, inhibit the RTS messages from becoming an aggressor against a transmitted LTE-U signal, for example. Further advantages achieved according to the embodiments disclosed herein include, without limitation, regeneration of an initial LTE-U signature, as well as tracking an LTE-U OFF period of the duty cycle with a certain probability threshold. The embodiments herein further enable the capability to extract the envelope of an LTE-U signal utilizing dedicated hardware, such as an RF detector, which could apply a first derivative on the time envelope of the LTE-U signal, and/or trigger a bistable circuit, for example.
• Exemplary embodiments of shared access communication management systems and methods are described above in detail. The systems and methods of this disclosure though, are not limited to only the specific embodiments described herein, but rather, the components and/or steps of their implementation may be utilized independently and separately from other components and/or steps described herein.
• Although specific features of various embodiments of the disclosure may be shown in some drawings and not in others, this convention is for convenience purposes and ease of description only. In accordance with the principles of the disclosure, a particular feature shown in a drawing may be referenced and/or claimed in combination with features of the other drawings.
• Some embodiments involve the use of one or more electronic or computing devices. Such devices typically include a processor or controller, such as a general purpose central processing unit (CPU), a graphics processing unit (GPU), a microcontroller, a reduced instruction set computer (RISC) processor, an application specific integrated circuit (ASIC), a programmable logic circuit (PLC), a field programmable gate array (FPGA), a digital signal processing (DSP) device, and/or any other circuit or processor capable of executing the functions described herein. The processes described herein may be encoded as executable instructions embodied in a computer readable medium, including, without limitation, a storage device and/or a memory device. Such instructions, when executed by a processor, cause the processor to perform at least a portion of the methods described herein. The above examples are exemplary only, and thus are not intended to limit in any way the definition and/or meaning of the term “processor.”
• This written description uses examples to disclose the embodiments, including the best mode, and also to enable any person skilled in the art to practice the embodiments, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

Claims (22)

What is claimed is:

1. A method for detecting aggressive signal transmission signatures in a wireless communication network including at least one station, at least one access point, and at least one non-cooperative transmission source, the method comprising the steps of:

generating a matrix of each instance of request-to-send (RTS) messages received by the at least one access point during a specified observation cycle;

recording, in a memory of the at least one access point, a number of cumulative RTS messages received from the at least one station;

calculating a cumulative distribution function (CDF), based on the recorded RTS message instances in the memory, for a probability of the presence of an aggressive transmission signal by the at least one non-cooperative transmission source within a transmission range of the at least one access point; and

determining the presence of the aggressive transmission signal based on the calculated CDF being greater than a predetermined threshold.

2. The method ofclaim 1, wherein the at least one access point utilizes a distributed access protocol relating to one or more of Wi-Fi, Bluetooth, and Zigbee technologies.

3. The method ofclaim 1, wherein the at least one non-cooperative transmission source utilizes an unlicensed long term evolution protocol.

4. The method ofclaim 1, wherein the wireless communication network includes a plurality of stations, and wherein, in the step of recording, a number of cumulative RTS messages are recorded in the memory for each of the plurality of stations.

5. The method ofclaim 1, wherein data of the generated matrix is stored within the memory of the at least one access point.

6. The method ofclaim 1, further comprising a step of increasing a detection interval during the specified observation cycle when the calculated CDF is below the predetermined threshold.

7. A method for detecting aggressive signal transmission signatures in a wireless communication network including a plurality of stations, a plurality of access points, and at least one non-cooperative transmission source, the method comprising the steps of:

transmitting a first cooperative transmission signal from a first one of the plurality of access points to a selected one of the plurality of stations;

issuing a carrier sense clear channel assessment, by a second one of the plurality of access points, to one or more of the plurality of stations and of the plurality of access points;

completing the transmission of the first cooperative transmission signal upon commencement of an aggressive transmission by the at least one non-cooperative transmission source;

sending, from the second one of the plurality of access points, a clear-to-send (CTS) message to one or more of the plurality of stations and of the plurality of access points;

detecting, by the second one of the plurality of access points, an energy of the aggressive transmission; and

determining, by the second one of the plurality of access points, the presence of the aggressive transmission based on the detected energy.

8. The method ofclaim 7, further comprising a step of requesting, by the second one of the plurality of access points, radio measurements on one or more channels within transmission range of the second one of the plurality of access points.

9. The method ofclaim 8, further comprising a step of selecting, by the second one of the plurality of access points, and idle channel from the one or more channels.

10. The method ofclaim 7, further comprising a step of analyzing, by one or more of the first and second ones of the plurality of access points, a shared spectrum of the wireless communication network to model a signature and/or pattern of the aggressive transmission.

11. The method ofclaim 10, wherein the step of analyzing is performed based on multiple queries of the shared spectrum by the one or more of the first and second ones of the plurality of access points.

12. The method ofclaim 11, wherein the step of analyzing further comprises sampling spectral data of the shared spectrum.

13. The method ofclaim 12, further comprising a step of calculating the bounds of one or more of detected Wi-Fi energy and the detected interference energy from the sample spectral data.

14. The method ofclaim 12, further comprising a step of creating square wave signals from the sampled spectral data.

15. The method ofclaim 14, further comprising a substep of determining one or more of the periodicity and the duty cycle of the created square wave signals.

16. The method ofclaim 14, further comprising a substep of discarding nonconforming square wave data.

17. The method ofclaim 14, further comprising a step of re-analyzing the shared spectrum to measure noise levels therein.

18. A wireless communications system, comprising:

a first access point including a memory, a processor, and a transceiver, and configured to wirelessly send and receive cooperative transmission data;

a first electronic station configured to wirelessly communicate with the first access point and process the cooperative transmission data; and

at least one electronic aggressor transmission source configured to wirelessly send and receive aggressive transmission data within a transmission range of the first access point,

wherein the transceiver is configured to receive request-to-send (RTS) messages from the first electronic station at a selected cadence for a specified observation cycle,

wherein the access point is configured to record the received RTS messages in the memory, and

wherein the processor is configured to determine a transmission signature of aggressive transmission data based at least in part on a cumulative distribution function (CDF) of the stored RTS messages in the memory.

19. The system ofclaim 18, wherein the first station comprises a Wi-Fi device.

20. The system ofclaim 18, wherein the at least one electronic aggressor transmission source utilizes an unlicensed long term evolution protocol.

21. The system ofclaim 18, wherein the first access point is further configured increase the cadence in response to the CDF of the RTS messages falling below a predetermined threshold.

22. The system ofclaim 18, wherein the first access point is further configured increase a detection interval upon determining that an aggressive transmission signal is not detected within the observation cycle at a prescribed confidence level.

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