155 results about "Logical link control" patented technology

A frame scheduling entity (FSE) for a station having a point coordinator (PC) in a basic service set (BSS) in a wireless local area network (WLAN) is disclosed. The FSE is located at a medium access control (MAC) sublayer of the station, and includes a scheduling table and a scheduling element. The scheduling table is logically located at a medium access control (MAC) sublayer of the station, and contains at least one entry corresponding to a session admitted to transmit traffic over the wireless network. The entry contains a virtual stream (VS) identifier (VSID), a QoS parameter set, and a data size that are each associated with the session. The scheduling table also includes a permanent entry containing a null QoS parameter set and corresponding to best-effort (asynchronous) traffic from the PC to a non-PC station associated with the PC. The scheduling element schedules transmission of a data frame for a session between peer logical link control (LLC) sublayer entities of the BSS based on the information contained in the entry for the session. The data frame scheduled by the scheduling element is labeled by the VSID contained in the entry.

Disclosed herein are exemplary techniques for initiating a direct wireless link between two wireless devices. The system and method include transmitting, from a first wireless device, a first frame having a destination media access control (MAC) address of the second wireless device, wherein the first frame includes direct link information encapsulated at the logical link control level; receiving, at the first wireless device, a second frame from a second wireless device, the second frame having a destination MAC address and being intended for the first wireless device, wherein the second frame includes direct link information encapsulated at the logical link control level; and establishing a direct wireless link between the first wireless device and the second wireless device when a third frame is transmitted from the first wireless device, the third frame having a destination media access control (MAC) address of the second wireless device, wherein the third frame includes direct link information encapsulated at the logical link control level.

A station, such as a point coordinator (PC) or a non-PC station, in a basic service set (BSS) in a wireless local area network (WLAN) is disclosed. The station includes a frame classification entity (FCE), a frame scheduling entity (FSE) and a QoS management entity (QME). The FCE is logically located in a logical link control (LLC) layer of the station and has a classification table containing at least one classifier entry. Each classifier entry contains a virtual stream identifier (VSID) and a frame classifier associated with a user session. The FCE receives a data frame associated with the user session, which can be one of a voice session, a video session, a data session and a multimedia session. The data frame contains in-band quality of service (QoS) signaling information for the user session. The FCE classifies the received data frame to a selected VSID contained in a classifier entry in the classification table based on a match between an in-band frame classification information contained in the received frame and the frame classifier contained in the classifier entry. The FSE is logically located in a medium access control (MAC) sublayer of the station and has a frame scheduling table containing at least one entry. Each entry in the frame scheduling table contains a VSID and a QoS parameter set associated with a user session identified by the VSID. The FSE is responsive to the classified data frame by scheduling a transmission opportunity (TO) for the classified data frame based on the at least one QoS parameter value associated with the VSID and characterizing the user session. The QME interfaces with the FCE and The FSE.

The invention discloses a charging-discharging system for a V2G bilateral power conversion electric automobile and a control method thereof, which belong to the technical field of intelligent power grids. In the charging-discharging system, a single-phase or three-phase voltage PWM (Pulse Width Modulation) converter (VSC) is taken as a first-grade power conversion circuit, so that energy conversion between an alternating-current power grid and a first direct-current bus is realized; and a symmetric half-bridge LLC (Logical Link Control) resonant bilateral direct current-direct current (DC/DC) converter is taken as a second-grade power conversion circuit, so that energy conversion between a direct-current bus and a power battery pack is realized. The charging-discharging system has the beneficial effects that: the current of the converter power grid side of the first-grade power conversion circuit is approximate to sine wave, so that the harmonic content is small; and the converting efficiency, dynamic performance and power density of the second-grade power conversion circuit are increased, the volume and weight of a charging-discharging device of the electric automobile are reduced, and the safety, reliability and economic efficiency of the system are improved effectively.

The invention relates to a digital control device and method for an LLC (logical link control) synchronously-rectified resonant converter. The device comprises a digital signal processor, a primary high-frequency driving circuit, a current sampling detection circuit, a voltage sampling detection circuit and a secondary high-frequency driving circuit, wherein the digital signal processor judges an operation area of a circuit according to an output voltage fed back by the voltage sampling detection circuit, after the circuit performs three-pole two-zero compensation, the values of an on-chip period register are respectively changed so as to generate high-frequency driving signals which are then output to the primary and secondary high-frequency driving circuits by the digital signal processor; the current sampling detection circuit detects a secondary output current which is then output to the digital signal processor, then the digital signal processor judges whether an overloading or overcurrent phenomenon (generated in the process of area switching) occurs according to the size of the current so as to cut off the primary and secondary high-frequency driving circuits in time. In the invention, the LLC resonant converter is subjected to the following digital control by a digital signal processing chip-peripheral timer combined circuit: the advanced conduction of secondary synchronous rectifying tubes is realized by the design of software/hardware auxiliary circuits, and the control on secondary driving signals is performed by adding a 555 timer, so the application of a timer in a DSP (digital signal processing) chip is reduced, thereby effectively solving the problem of conduction loss of synchronous rectifying tubes introduced in the process of underloading in the traditional control strategy; and the application of a PWM (pulse-width modulation) port of the digital signal processing chip is reduced, thereby improving the reliability of the whole device.

Methods and systems for processing data are disclosed herein and may include compressing audio information on-chip within a Bluetooth® transceiver chip utilizing an audio codec implemented within the Bluetooth® transceiver chip. The audio codec may be a low complexity sub-band codec (SBC). An audio stream with the audio information may be generated outside the Bluetooth® transceiver chip. The audio stream may be generated via an audio/video distribution transport protocol (AVDTP) external to the Bluetooth® transceiver chip. A data channel may be established by the Bluetooth® transceiver chip between a Bluetooth® enabled device and a peer Bluetooth® device, for communicating the established audio stream to the Bluetooth® transceiver chip for compression. The data channel may be established utilizing a logical link control and adaptation protocol (L2CAP) and/or an advanced audio distribution profile (A2DP).

The invention discloses a positive and negative pulse charging converter for a storage battery. A bilateral full-bridge LLC (Logical Link Control) resonant circuit is taken as a main charging topology, so that the defect that the implementation of negative pulses is limited by application occasions and power levels is overcome while soft switching is realized. Meanwhile, a power main circuit comprises a bridge type uncontrollable rectifying circuit and a bilateral full-bridge LLC resonant circuit. During discharging of the storage battery, the bus capacitive voltage on a high-voltage side, namely, a rectifying side is raised. During initial charging at a positive pulse charging stage, open-loop control is adopted, namely, the duty ratios and frequencies of switching tubes Q1-Q4 are kept the same as the duty ratios and frequencies in a previous charging period. Since the bus capacitive voltage is high, the charging current is increased correspondingly and decreased gradually till a charging controller works normally, and the charging current is stable. In this way, sharp pulse charging current is formed in order to enhance the repair, namely, depolarization effect of the storage battery. Moreover, both the charging current and discharging current of the storage battery are under high-frequency pulsation, and an LC filter filters higher harmonics of the charging current while smoothening the high-frequency pulsation.

A novel software architecture protocol stack with embedded routing algorithms under the Internet Protocol (IP) routing layer in order to provide high quality distribution of multimedia (voice, video, and data) services. These routing algorithms may include Logical Link Control, Adaptive Transmission Protocol, Neighbor Discovery, Traffic Control, Ad-Hoc Routing, Flow Processing, Intelligent Access and Admission Control. These routing algorithms when implemented further provide for advantages in speed of service, reliability of service, self-healing in case of catastrophic failure of an infrastructure component, load-balancing and geographic reuse.

A method and system for communicating packet data units over a Gb interface in a wireless communication environment is provided. Packed Data Units (PDUs) are received from Machine Type Communication (MTC) device(s) by a base station coupled to the MTC device(s). Then, the PDUs are aggregated over a period of time by the base station. Further, the aggregated PDUs are packed in at least one Logical Link Control (LLC) data packet. The at least one LLC data packet including the aggregated PDUs is multiplexed over a Gb interface in a single session between the base station and a packet core network.

The invention relates to a design of a single-stage AC/DC (alternating current-direct current) high-power LED (light-emitting diode) lighting driver. A PFC (power factor correction) circuit with bridgeless boost topology and a half-bridge resonant LLC (logical link control) circuit are organically combined, and the functions of outputting pulse current to drive an LED for lighting, soft-switching a power switching tube and realizing high power factor and low harmonic of input current of a power grid by sharing the power switching tube and a small-capacitance capacitor device, and the driver can simultaneously reduce the number of power devices, reduce the cost of the driver and improve the reliability of the driver. The switching tube in the driver disclosed by the invention works under the conditions of high frequency and fixed duty ratio, and a control circuit is simple. The driver disclosed by the invention can eliminate a large-capacitance electrolytic capacitor on the DC side of the traditional PFC circuit, the capacitor in the designed circuit can be simultaneously used as a resonant capacitor of an LLC half-bridge resonant circuit, and the adverse effects of the electrolytic capacitor on the long service life of the LED can be avoided. The driver disclosed by the invention can output the low-frequency pulse current to drive an LED lamp and is applicable to the field of general lighting.

The invention relates to a control device and method for an interleaved parallel LLC (Logical Link Control) resonant converter. The device comprises a set of interleaved parallel LLC resonant converter main circuit (100) and is characterized in that the interleaved parallel LLC resonant converter main circuit (100) is controlled by a control circuit based on a full bridge phase-shift chip UCC3895; when the circuit works at a light load, the output pulse width of a chip UCC3895 (108) is adjusted through a dead zone feedback compensation link; when the circuit works at a heavy load, the output frequency of the chip UCC3895 (108) is adjusted through a frequency-adjusting feedback compensation link; and equalizing current of a secondary circuit is improved by modifying a connecting mode of a coupling transformer of the interleaved parallel LLC resonant converter main circuit (100) and a primary end. According to the invention, the interleaved parallel LLC resonant circuit is not limited by application occasions of a traditional LLC main control chip and is suitable for high-power occasions; the circuit is simplified; and the robustness is improved.

Disclosed are LLC (logical link control) converter synchronous rectification method and device. The method includes: acquiring an output voltage signal and an output current signal of a converter; calculating switching frequency of a primary side field-effect transistor according to the output voltage signal and the output current signal; judging operating statuses of the converter according to resonant frequency of the converter, and calculating different primary- and auxiliary-side frequencies and duty ratios according to the different operating statuses; controlling on and off of the primary- and auxiliary-side field-effect transistors to allow output synchronous rectification drive signals to open in the discontinuous operating status of the converter and shut down in the continuous operating status of the converter. By the use of the LLC converter synchronous rectification method and device, excessive loss due to non-zero open or shutdown current is reduced when synchronous rectifier tubes operate, and system efficiency is improved.

The invention discloses a data transmission method, a relay node, a convergence server and a system, wherein the method comprises the steps of: 1) establishing a plurality of tunnel connections between the relay node and the convergence server through a plurality of wireless access network elements; 2) conducting logical link control packaging on uplink IP groups uploaded by a mobile terminal through the relay node to form an uplink logical link control message; and 3) sending the uplink logical link control message to the convergence server by the relay node. The data transmission method, the relay node, the convergence server and the system has good compatibility and good extensibility, the RN (relay node) supports a plurality of LTE (Long Term Evolution) wireless access network elements, only a link application layer is corrected, only the convergence server is added, and an air interface protocol is not required to be corrected.

The invention discloses an AC (alternating-current)/DC (direct-current) converter, comprising a PFC (power factor correction) circuit and a DC/DC converter coupled with one output end of the PFC circuit, wherein the PFC circuit is a PFC circuit without a rectifying bridge; the DC/DC converter comprises an LLC (logical link control) circuit, a transformer and a synchronous rectifying circuit; the output end of the PFC circuit is connected with an input end of the LLC circuit; an output end of the LLC circuit is connected with a primary winding of the transformer; and a secondary winding of the transformer is connected with an input end of the synchronous rectifying circuit. The AC/DC converter can reduce circuit losses and improves power supply efficiency and power density.

A Bluetooth communication system is provided wherein a remote, or destination, wireless communication device provides its Bluetooth profile information, including all of the necessary Service Discovery Protocol (SDP) information required to initiate a profile connection, to a source wireless communication device in an Extended Inquiry Response (EIR) message as part of Device discovery or Inquiry procedure. In response, the source wireless communication device will establish an ACL connection with the remote wireless communication device and provide its own EIR message containing the necessary SDP information of the source wireless communication device over ACL connection as an ACL data packet. The manufacturer data field of the EIR messages will include the SDP information of the respective devices. Thus the Bluetooth communication system preserves the overhead that would be expended in establishing a Layer Logical Link Control and Adaption Protocol layer (L2CAP) connection and exchanging multiple SDP requests and responses.

The invention discloses a double-transformer serial and parallel structure full-bridge LLC (logical link control) resonant converter, and belongs to the technical field of DC/DC converters. The double-transformer serial and parallel structure full-bridge LLC resonant converter comprises a main circuit and a control module, wherein the main circuit comprises an input direct-current source, a full-bridge switching network, an LLC resonant network, a secondary rectifier filter circuit and a battery pack load which are sequentially connected, and the control module comprises an output voltage sampling circuit, an output current sampling circuit, a feedback adjusting circuit, a control chip and a driving circuit. The full-bridge LLC resonant converter is provided with a double-transformer serial and parallel structure, primary windings of two transformers are serially connected, current flowing through the primary windings is the same, secondary current can be automatically balanced, turns of the primary windings are decreased, current stress of secondary windings and rectifier diodes can be reduced by secondary parallel connection, the size of a magnetic core can be decreased by the double-transformer serial and parallel structure, hot spots can be dispersed, heat management is facilitated, and the full-bridge LLC resonant converter is applicable to places with medium-high power electric vehicle chargers.

The present invention relates to a method of selective setting of retransmission time-out values in a mobile, radio communication system. A mobile station (MS1) communicates with a base station system (BSS). The mobile station (MS1) can be in any cell in a public land mobile network (PLMN). The base station system (BSS) communicates with a serving GPRS support node (SGSN). A parameter T200D is representing retransmission time-out in downlink direction and a parameter T200U is representing retransmission time-out in uplink direction, between the mobile station (MS1) and the serving GPRS support node (SGSN). Both parameters T200D and T200U replace the T200 parameter. If the logical link control (LLC) connection is in asynchronous balanced mode (ABM) then at chosen time intervals the T200D and T200U are measured and if required negotiated.

The invention discloses a full-bridge soft switch medical X-ray machine high-voltage direct-current power supply, which comprises a full-bridge inverter circuit, an LLC (Logical Link Control) serial resonance circuit, a high-frequency high-voltage transformer, a voltage doubling rectifying circuit and a control module. An LLC serial resonance technology is adopted for the full-bridge soft switch X-ray machine high-voltage direct-current power supply, and an overlapping region does not exist between voltage and current, so that soft switch is realized, the switching loss of a switch tube is lowered, the switching frequency and output power of the converter are further increased, and the direct-current power supply has the characteristics of small size and light weight; and moreover, frequency modulation control is adopted for the high-voltage direct-current power supply, and the output voltage is not influenced by the duty factor loss, so that the adjusting range of the output voltage is widened, and the performance of the X-ray machine power supply is enhanced.

The invention relates to a switching frequency adjusting method based on current cross feedback, aims to solve the problem of power sharing control for input-series-output-parallel (ISOP) modular LLC (Logical Link Control) resonant DC-DC (Direct Current-Direct Current) converters, and belongs to high-voltage direct-current input applications in the field of power electronics. According to the method, output voltages and output currents of modules are sampled, and switching frequencies of the modules are adjusted through cross current feedback and kept within a range in which input impedance of an LLC converter monotonically increases progressively along with the switching frequencies, so that input impedance of the modules is the same during normal working, thereby realizing power sharing. The method has the advantages of easiness in control, high conversion efficiency of a whole system, high dynamical response speed, high stability and unlimited module quantity.

The invention provides a Bluetooth-WIFI gateway enabling a Bluetooth device and a WIFI device to be communicated transparently. A central processing unit is connected with a Bluetooth module and a WIFI module through serial ports and is used for converting and transmitting converted data of the Bluetooth module to the WIFI module or converting and transmitting data of the WIFI module to the Bluetooth module. The Bluetooth module of the gateway is communicated with a Bluetooth terminal through a piconet. The WIFI module and the WIFI device of the gateway are communicated through a wireless network. A protocol model of the Bluetooth-WIFI gateway comprises a Baseband, a link management protocol (LMP), a logical link control and adaptation protocol (L2CAP), a Bluetooth network encapsulation protocol (BNEP), a service discovery protocol (SDP), a Physical layer, a Datalink layer, a Network layer and a Transport layer, wherein the Baseband, the LMP, the L2CAP, the BNEP and the SDP correspond to Bluetooth, and the Physical layer, the Datalink layer, the Network layer and the Transport layer correspond to WIFI. A routing layer of the Bluetooth-WIFI gateway is upmost. The Bluetooth-WIFI gateway is provided with the virtual Bluetooth device and the virtual WIFI device, and existing routing mechanism is changed appropriately so as to achieve the communication between the Bluetooth device and the WIFI device.

A method and device according to the present invention reorders Logical Link Control (LLC) Packet Data Units (PDUs) when user data is transferred over the radio interface between a Mobile Station (MS) and a packet data network. An objection of the present invention is to provide a method and system for transferring user data over a network ensuring the best quality of service characteristics.

The invention relates to the technical field of circuits, and discloses a three-level LLC direct-current converter and a control method of the three-level LLC direct-current converter. The method comprises the following steps of: controlling the converter by a hybrid control manner of a PFM (Pulse Frequency Modulation) and a PWM (Pulse Width Modulation); adjusting the duty ratio of a switch tube of the converter under a PWM state, carrying out synchronous adjusting on the second switch tube and the first switch tube in four switch tubes which are sequentially connected in series, and carrying out synchronous adjusting on a third switch tube and a fourth switch tube. By utilizing the three-level LLC direct-current converter and the control method of the three-level LLC direct-current converter, the consumption of a clamping diode in a clamping circuit can be reduced, and the cost can be further lowered by selecting a diode in a smaller size as well.