Abstract: The present disclosure discloses a method for automatically identifying south troughs by improved Laplace and relates to the technical field of meteorology. The method includes the following steps: acquiring grid data of a geopotential height field; calculating a gradient field of the geopotential height field in an x direction; searching for a turning point where a gradient value turned from being negative to being positive, and cleaning the gradient field; calculating a divergence of the x direction to obtain an improved Laplacian numerical value L?; performing 0,1 binarization processing on the L? to obtain a black-and-white image and a plurality of targets of potential troughs, merging the black-and-white image and the plurality of targets of the potential troughs by expansion, recovering original scale through erosion, and selecting an effective target through an angle of direction of a contour and an axial ratio.

Abstract: Systems and methods are disclosed by which base stations with overlapping service areas allocate frames within superframes of a channel in a cognitive radio communication network. The frames are assigned for sole use by a base station on a frame-by-frame basis using a Frame-Based, On-Demand Spectrum Contention process. The process resolves contentions for use of frames using equally probable random numbers. The results of the process are transmitted and received between base stations using vector messages. Applications of the methods and systems include Wireless Regional Area Networks (WRANs), including those using the standards of IEEE 802.22.

Abstract: A first base station is associated with a first quiet period, and a second base station is associated with a second quiet period. The quiet periods are coordinated so that an amount of overlap between the quiet periods is acceptable. For example, the quiet periods could be coordinated so that no overlap exists between the quiet periods. During the first quiet period, the first base station and/or an associated device (such as a CPE served by the first base station) performs in-band sensing to detect wireless devices that use a first frequency or channel also used by the first base station. During the second quiet period, the first base station and/or a coordinate device (such as a CPE served by the first base station and assisting the second base station) performs out-band sensing to detect wireless devices that use a second frequency or channel also used by the second base station.

Abstract: Radio frequency (RF) architectures for spectrum access networks are provided. Embodiments of the invention generally provide a radio frequency (RF) architecture for customer premise equipment (CPE) for use in, for example, IEEE 802.22 wireless regional area networks (WRANs). In some embodiments, the CPE RF architecture includes two receive chains with a directional antenna and an omni-directional antenna, respectively. The CPE RF architecture facilitates opportunistic out-of-band spectrum sensing and WRAN signal receiving that are performed in parallel with data transmission.

Abstract: A protocol for inter-cell communication in a cognitive radio wireless access network using beacon period framing is disclosed. By establishing scheduled use of beacon periods within each frame of a super-frame among a plurality of participating cells in a wireless access network, efficient and reliable communication can take place eliminating beacon packet collisions and bandwidth wastage. Within each super-frame exits 16 data frames of fixed size which can each include both a data transmission portion and a beacon period. A protocol is established by which announcement, reserved, and free-to-use beacon periods are established within the super-frames associated with a particular spectrum. By coordinating communication between cells on the beacon period, collision between cells by simultaneous attempts to transmit or bandwidth wastage of periods in which no transmission takes place can be avoided.

Abstract: The invention relates to systems and methods for spectrum sharing and communication among several wireless communication networks with overlapping service areas (or cells), especially to Wireless Regional Area Networks (WRANs). Particular embodiments of the invention disclose using a conference channel to communicate between base stations. Other embodiments use slotted coexistence windows within frames to transmit and receive information, including for reserving transmission times within subsequent frames.

Abstract: A protocol for resolving shared spectrum contentions in cognitive radio wireless access networks is presented. Using medium access control level messaging a request for access to a shared spectrum is conveyed to the current occupier of the spectrum. Each request is associated with a unique and random spectrum access priority number. At the end of a request window the priority numbers associated with each request are compared and a winner is declared. The winning cell, informed of its newly gained access to the shared spectrum, sends a reply to the current occupier of the shared spectrum with a proposed time of acquisition/release of the shared spectrum. The proposed time is confirmed and announced, and upon arrival of the designated time the shared spectrum is released by the current occupier of the shared spectrum and acquired by the requesting cell.

Abstract: For enhanced interoperability of safety and non-safety communications, a synchronous interval is divided into a safety channel interval and an open interval instead of a CCH (control channel) interval and SCH (service channel) interval. For a single-radio device, a control interval, in place of an open interval should be scheduled at least once every maximum service scheduling period. Such a control interval is dedicated for CCH (and SCH) operation. For a multi-radio device, a control interval is scheduled at least once every maximum control interval on one of the radios support non-safety services (e.g. tolling).

Abstract: For enhanced interoperability of safety and non-safety communications, a dual-radio type T RSU for improving services includes a first radio dedicated to the control channel and a second radio dedicated to the safety channel. The control channel is divided into a number of synchronous intervals, each about 100 milliseconds in duration. The safety channel is also divided into a number of synchronous intervals, each about 100 milliseconds in duration.

Abstract: In order to satisfy the conflicting requirements for spectrum sensing and QoS of data transmission, it is highly desirable for a cognitive radio system, e.g. IEEE 802.22 WRAN, to perform spectrum sensing and data transmission simultaneously. Embodiments of the invention address critical issues of self-interference generated from a transmission unit to the co-located sensing unit when the simultaneous sensing and data transmission technique is applied. A number of interference mitigation techniques are described and analysis are given.

Abstract: Systems and methods are disclosed by which base stations with overlapping service areas allocate frames within superframes of a channel in a cognitive radio communication network. The frames are assigned for sole use by a base station on a frame-by-frame basis using a Frame-Based, On-Demand Spectrum Contention process. The process resolves contentions for use of frames using equally probable random numbers. The results of the process are transmitted and received between base stations using vector messages. Applications of the methods and systems include Wireless Regional Area Networks (WRANs), including those using the standards of IEEE 802.22.

Abstract: Discovery of safety and non-safety capable single-radio devices in vehicular wireless environments is made possible through the use a two-bit indicator. A first indicator is associated with a type C device. A second indicator is associated with a non-type C device within one hop of a type C device. A third indicator is associated with a non-type C device within two hops of a type C device. A fourth indicator is associated with a non-type C device within three hops or more (out of range) of a type C device. Discovery of safety and non-safety capable single-radio vehicular devices within a protection range in multiple-channel based wireless vehicular environments is thus made possible.

Abstract: A hierarchical WRAN includes a relay station (RS) possessing dual roles. A RS acts from the perspective of a base station (BS) as a consumer premise equipment (CPE) terminal just as any other first tier CPE terminal. Simultaneously, the RS, from the perspective of other second tier CPEs, acts as a BS providing all of the functional capabilities of a BS. The RS includes dual medium access control (MAC) functions in which a first MAC function serves to interface the RS with the BS while the second MAC function serves to interface the RS with the at least one CPE terminal. The RS further includes a convergence layer that maps, at the RS, the first MAC to the second MAC. The dual MAC capability of the RS enables the RS to pipeline frame transmission in both single and multi-channel operations.

Abstract: The invention discloses frame-based, on-demand spectrum contention methods and systems to share spectrum resources in cognitive radio networks in general and in Wireless Regional Area Networks (WRANs) having overlapping service areas in particular. As demand for increased spectrum usage arises, frames within synchronized superframes are allocated, on a frame-by-frame basis, based on independently chosen, equiprobable random numbers generated for each base station contending for transmission/reception use of the frames.

Abstract: Radio frequency (RF) architectures for spectrum access networks are provided. Embodiments of the invention generally provide a radio frequency (RF) architecture for customer premise equipment (CPE) for use in, for example, IEEE 802.22 wireless regional area networks (WRANs). In some embodiments, the CPE RF architecture includes two receive chains with a directional antenna and an omni-directional antenna, respectively. The CPE RF architecture facilitates opportunistic out-of-band spectrum sensing and WRAN signal receiving that are performed in parallel with data transmission.

Abstract: This invention relates to cognitive radio based wireless communications of dynamic spectrum access networks, and more particularly to a method of addressing inter-systems (cells) coexistence and spectrum sharing. The described method of spectrum sharing called On-Demand Spectrum Contention, integrates Dynamic Frequency Selection and Transmission Power Control with iterative on-demand spectrum contentions and provides fairness, adaptability, and efficiency of spectrum access for dynamic spectrum access systems using active inter-system coordination.

Abstract: This invention relates to cognitive radio based wireless communications of dynamic spectrum access networks, and more particularly to a method of addressing inter-systems (cells) communications for coexistence and spectrum sharing. A method, called Logical Control Connections, is described for reliable connection-based inter-system coordination and communications, which can be established and maintained either over the air or over the backhaul with very low incurred communications overhead in terms of spectrum bandwidth, messaging latency, and hardware/software complexities.

Abstract: Systems and methods are disclosed by which base stations with overlapping service areas allocate frames within superframes of a channel in a cognitive radio communication network. The frames are assigned for sole use by a base station on a frame-by-frame basis using a Frame-Based, On-Demand Spectrum Contention process. The process resolves contentions for use of frames using equally probable random numbers. The results of the process are transmitted and received between base stations using vector messages. Applications of the methods and systems include Wireless Regional Area Networks (WRANs), including those using the standards of IEEE 802.22.

Abstract: Methods and systems are disclosed for interoperations between single-radio (channel switching) devices, dual radio devices, and single-radio (always-on) devices in radio communication systems, both with and without a safety channel. The methods and systems may be applied in communication systems for wireless access in vehicular environments (WAVE), such as those according to IEEE 802.11p. When there is a safety channel, some embodiments add a Safety Channel Interval within an operation period. Other embodiments disclose how various device types can operate to coordinate safety message transmissions, both with and without a safety channel.

Abstract: A self-coexistence window reservation protocol for a plurality of Wireless Regional Area Network (WRAN) cells operating in a WRAN over a plurality of channels includes a sequence of self-coexistence windows that uniquely identifies a transmission period for each WRAN cell. A self-coexistence window reservation protocol is included within the first packet of a Coexistence Beaconing Protocol period identifying when each WRAN cell associated with a particular channel will transmit. When not actively transmitting, a WRAN cells remains in a passive, receiving mode to accept data. As the transmissions of each WRAN cell operating on a particular channel are scheduled, contention for a transmission period is eliminated.