178 results about "Collision rate" patented technology

The present invention discloses a method for increasing the channel capacity of a communications network, comprising a plurality of one-way TDMA transmitters sharing said channel, and at least one compatible receiver, by reducing transmission collisions among said transmitters. This is achieved by coupling a Global Navigation Satellite System (GNSS) decoder, such as a GPS receiver, to each transmitter, and limiting transmissions to discrete time slots, determined by timing signals provided by said GNSS. Further, this basic set of time slots is divided into several sub sets, and each transmitter selects a sub set of time slots according to its geographic location, in order to enable reusing time slots in spaced apart areas, as frequencies are reused in cellular networks. Then, each transmitter selects its own transmission time slot, from said sub set, in a way that statistically minimizes collisions among nearby transmitters. The present invention does not intend to ensure collision-free communications, yet is projected to reduce the transmission collision rate among simplex in nature transmitters, which have no means to detect other transmissions, or discover if a transmission was successful. One embodiment of this invention is related to distress radio beacons in satellite based Search and Rescue (SAR) systems, such as Cospas-Sarsat.

The present invention relates to wireless communications. More especially it relates to wireless packet data communications. Particularly it relates to latency reduction when scheduling a plurality of temporarily inactive users or TBFs for a communications resource. Users or TBFs are pooled at controlled collision rate.

A connection engine and coexistence manager are employed to manage radio resources in a user equipment. The connection engine defines desired performance metrics for sets of radio resources. The coexistence manager allocates potentially interfering radio resources to achieve desired performance metrics while accounting for resource capacity, potential collision rates, and other metrics.

A frequency hopping sequence generator system (40) for use in a radio telecommunications system utilizes variable frequency offsets (FO) to determine a frequency hopping sequence for use in communication between a mobile station and a network node. The frequency hopping sequence generator comprises a frequency offset hopping generator (42) which chooses the variable frequency offsets so that the frequency hopping sequence provides intra-cell interference diversity. For each mobile station, the frequency offset hopping generator determines a frequency offset index (FOI) which is mapped to one of plural possible frequency offsets (FO). The frequency offset index (and thus the corresponding frequency offset) is determined to provide the frequency hopping sequence with both interference diversity and orthogonality. The frequency offset index has a first component and a second component. The first component of the frequency offset index is an inter-cell component that provides, e.g., collision diversity between FO hopping sequences that are not orthogonal. The second component is an intra-cell component that provides orthogonal (non-colliding) sequences with a variable difference between two sequences. The intra-cell component sub-generator can operate in either a “short sequences” mode or a “long sequences” mode. The long sequences mode renders adjacent frequency collision rates between two sequences with equal FOHSN independent of the choice of the two different FOSEEDs selected. On the other hand, the short sequences mode yields higher collision rates between certain pairs than between other pairs.

The invention discloses a self-adaptive random access method and system of a machine type communication terminal and belongs to the field of mobile communication. According to the method and system, a lead code is mainly sent through the machine type communication terminal, a base station sends a random access response message and makes judgment according to the connected terminal, a BO value is set adaptively based on the number of collision terminals, the collision rate of random re-access is reduced, and the access success rate is increased.

In a telecommunications system that employs frequency hopping techniques, network performance can be significantly improved by taking into consideration the level of interaction (e.g., the collision rate) between frequency hopping sequences, when allocating the frequency hopping sequences throughout the network. In a cellular network, this may be accomplished by deriving a network performance measure as a function of a current allocation of frequency hopping sequences for a number of cells and as a function of an expected collision rate (between the frequency hopping sequences) that appear for the current allocation. The frequency hopping sequences are then re-allocated amongst one or more cells until network performance is optimized. The allocation of frequency hopping sequences that results in optimized network performance may then be used for assigning frequency hopping sequences to new or existing connections (e.g., cellular calls) within a corresponding cell.

The invention relates to a device used for removing absorbable granules PM2.5 based on acoustic wave and with the addition of associative action of seed granules and a method thereof, in particular to a set of devices used for removing the absorbable granules (hereinafter called PM2.5 for short) with grain diameter less than 2.5 micrometers in dusty gas and a method thereof. The device comprises a sound source, an acoustic agglomeration chamber, a feedway for the seed granules, subsequent normal dedusting equipment, etc. When flue gas discharged by various combustion sources or other dusty gas flows through the acoustic agglomeration chamber, fine granules in airflow arise entrainment of different degrees under the action of the acoustic wave, while the added seed granules nearly do not arise entrainment due to relatively large inertia thereof; meanwhile, the fine granules and the seed granules are different in gravity settling and acoustic drift. The three reasons lead to relative movement between the fine granules and the seed granules, thus generating quite high collision rate between the absorbable granules PM2.5 and the seed granules. After the absorbable granules PM2.5 collide with the seed granules, agglomeration happens between the absorbable granules PM2.5 collide with the seed granules; coacervate generated by the agglomeration is further removed by the subsequent normal dedusting equipment.

The invention discloses an active obstacle avoiding method for a four-wheel hub drive electric automobile with multiple modes. The method aims at improving the obstacle avoiding capacity of the electric automobile, so that the travel safety of the electric automobile is improved. According to information of different automobile speeds and the real-time distance between the automobile and an obstacle, a control method with the multiple modes is adopted for properly controlling the four-wheel hub drive and braking electric automobile, and therefore active obstacle avoidance of the electric automobile is achieved. Especially in an emergency, the automobile can make a turn rapidly to avoid the obstacle through control over wheels on one side for braking and control over wheels on the other side for driving, and therefore the collision rate of the automobile and the short-distance obstacle is greatly reduced. Due to the fact that no steering input operation is related, the situation that a driver is panic due to the fact that steering assisting control and the decision making intension of the driver are different is avoided, the operation burden of the driver is reduced to a great extent, traffic accidents caused by mistaken steering operation conducted by the driver in the emergency are reduced, and the travel safety is improved.

The invention discloses a self-adaption adjustment method of contention windows in an 802.11e wireless network. A network load state is determined according to a network conflict rate via a wireless access point, and the contention windows are adjusted in a self-adaption mode according to the network load state. If the conflict rate is detected to be greater than a given threshold value, the access probability between an AP of current network load and an site is calculated in a multiplicative decrease mode according to an actual conflict rate value; if the conflict rate is detected to be smaller than or equal to the given threshold value, the access probability adapted for the current network load is calculated in a linear increase mode according to the actual conflict rate value. On this basis, an AP access probability is optimized according to the length of an AP current queue. Finally, the largest contention windows and the smallest contention windows between the AP and the site are respectively calculated according to the relations between the access probability and the contention windows. According to the method, the values of the contention windows can be adjusted in a self-adaption mode on the basis of network load conditions, so that the effective availability of a wireless channel is improved, network throughput is increased, and network delay is reduced.

The invention belongs to the field of electric power systems and relates to a two-dimensional numerical simulation method for an icing process of a power transmission line. Based on the lagrangian method, the invention provides the two-dimensional numerical simulation method for a surface rime icing process of the power transmission line. A Reynolds-averaged Navier-Stokes (RANS) equation and shear-stress-transport-k-omega (SST-k-omega) turbulence model of non-steady incompressible flow is solved by adopting a semi-implicit method for pressure linked equations (SIMPLE) algorithm on a staggered grid so as to obtain an air flow field; movement tracks of super-cooled water droplets in the flow field are tracked by adopting the lagrangian method to obtain the transient local collision rate of all control volumes on the surface of the power transmission line; solving is performed based on an icing thermodynamic equation established by a Messinger control volume method so as to obtain the rime icing temperature of all the control volumes, and the icing process is simulated by combining an icing time marching method. Indicated by results, predicted ice shapes are better fitted with test measurement data in literature, and therefore, the two-dimensional numerical simulation method for the icing process of the power transmission line is feasible and effective.

The invention provides an electrical power steering system with a side safety auxiliary function and a control method thereof, which aims to reduce the side collision rate of automobiles and guarantee the traveling safety. The electrical power steering system comprises an electronic control unit, and is characterized in that the electronic control unit is connected with a position / torque sensor of a steering wheel, a speed sensor, a speed acceleration sensor, a power motor and a current sensor thereof, a yaw velocity sensor and a side acceleration sensor. The power motor is connected with a steering mechanism of the automobile through a driving mechanism. The electronic control unit is also connected with distance testing sensors which are arranged at both sides of the automobile. On the basis that the traditional electrical power steering system provides the basis function of power-assisted steering for drivers, the invention also increases the function which uses the steering wheel torque to alert the side collision danger, uses the power motor to implement warning and danger elimination, is favorable for avoiding the automobile generating side collision with the objects at both sides, and increases the traveling safety.

The invention discloses a contention window adjusting method taking an 802.11e VoIP application as orientation. The method includes the steps that (1) the optimal network access probability TauAPopt of a wireless AP is calculated according to an access MAC layer parameter and a VoIP coding mode; (2) the optimal value CWminAP of the size of the minimum contention window and the optimal value CWmaxAP of the size of the maximum contention window of the AP are calculated according to the TauAPopt; (3) the average collision rate favgj in the jth period at the AP is calculated, and then the network access probability TauSTA of a site STA is adjusted according to the relation of the favgj and the threshold value fopt; (4) the maximum contention window and the minimum contention window of the site are calculated by the AP according to the TauSTA; the maximum contention window and the minimum contention window of the site are broadcasted by the AP by using a periodic Beacon frame. By means of the contention window adjusting method taking the 802.11e VoIP application as orientation, the effective availability of a wireless channel can be improved, the network throughput is improved, and the VoIP capacity is improved as well.

A LAN of the ethernet type employs CSMA / CD protocol for channel access by a plurality of network nodes. Each node includes a data processing system having a device driver and an adapter and transmits data packets to the LAN in accordance with the IEEE 802.3 standard. The adapter coupled is at one side to the network in either a half or full-duplex mode. The other side of the adapter is bound to the device driver which is dynamically tuned for reduced latency and increased network throughput, regardless of the transmitting mode of the node and the capture effect of the ethernet. Each device driver operates in a transmit chaining mode when the network is in a lightly loaded half-duplex, or full-duplex mode. The driver includes means for monitoring data packet collisions on a channel of the network. A "collision rate" or the percentage of data packets which were transmitted on the channel with collisions in a pre-selected time interval is calculated by the device driver. A "collision threshold" is assigned or calculated by the device driver. Data packets transmitted by each device driver are chained to increase network throughput when the "collision rate" is below the "collision threshold". Transmit chaining of data packets is disabled for the device driver when the "collision threshold" is exceeded on the channel.

Systems and methods for improving Long Term Evolution (LTE)-WiFi coexistence in a network, including configuring one or more LTE nodes for asynchronous access and synchronous transmission to bridge LTE and WiFi access modes. A channel is reserved for LTE transmission in the one or more LTE nodes, and a supplementary WiFi module is provided in the one or more LTE nodes for sensing the channel for occupancy and for broadcasting a reservation signal on the channel prior to the LTE transmission. Contention window sizes are scaled linearly by increasing the contention window sizes proportionally to a subframe collision rate to maintain throughput fairness to the WiFi, and synchronous transmission from the one or more LTE nodes to one or more User Devices (UEs) is performed by activating the unlicensed carrier for a reserved time period.

Various embodiments are described which may serve to improve spreading channel code selection in wireless technologies that employ two-stage ranging. For example, some of the embodiments enable a number of spreading codes to be reused at each network node (111, 112), potentially increasing the number of codes available to each remote unit and thereby reducing the collision rate. Rather than simply selecting a spreading channel code randomly, remote units (101-103), in some embodiments, select a spreading channel code based on one or more considerations such as pilot signal strength, remote unit location, a remote unit mobility level, and a priority class associated with the remote unit. Depending on the embodiment, network nodes can partition the spreading codes into groups and then assign link bandwidth to remote units based on the group associated with the code selected by that remote unit.

The invention discloses a realization method for a Q learning based vehicle-mounted network media access control (MAC) protocol. According to the method, a vehicle node uses a Q learning algorithm to constantly interact with the environment through repeated trial and error in a VANETs environment, and dynamically adjusts a competitive window (CW) according to a feedback signal (reward value) given by the VANETs environment, thereby always accessing the channel via the best CW (the best CW is selected when the reward value obtained from surrounding environment is maximum). Through adoption of the method, the data frame collision rate and transmission delay are lowered, and fairness of the node in channel accessing is improved.

Communication control apparatus provided in nodes forming a telecommunications network includes a transmission timing calculator responsive to the state of the phase of the own node to determine a timing at which the node transmits data. The calculator is responsive to a state variable signal transmitted by a neighboring node and reflecting the phase of the neighboring node to change the state of the phase of the own node in accordance with a time development rule. The calculator monitors a phase difference of the own node against the neighboring node to calculate, based on the difference, the ratio of collision on data transmission timing between the own and neighboring nodes. The stress value corresponding to the collision ratio is stored time-serially. A stress response function value is generated such that the stored stress value causes the time development rule to shift the phase with its value made at random.

The invention discloses a Zigbee information channel dynamic selection method based on real-time availability. In the invention, the concept of information channel availability is provided for the first time, the information channel availability is updated by the availability algorithm in real time, and information channels can be dynamically selected according to availability sequence in an information channel resource pool, which is marked by a broken line in the figure. Parameters for the information channel availability indicate the vacancy rate and communication quality of the information channel and show practical available conditions of the information channel. Therefore, the parameters for the information channel availability can be used for guiding selection of the information channel in practical data transmission, so as to provide a communication support, increase the data transmission success rate, and reduce the collision rate and retransmission rate to the largest extent. Based on the vacancy rate and quality of the information channel, data transmission results and other parameters, the invention provides the real-time availability algorithm. The real-time availability algorithm not only provides a high-quality vacant information channel with more selection chances, but also ensures the fairness of information channel selection to the largest extent and enables the information channel to be selected by relative fair chance, thereby improving the utilization rate of the information channel. In the invention, the strategy to build the information resource pool to manage information channel resources is provided; information channels are sequenced based on the parameters for the information channel availability; and the ZigBee information channel is selected according to the sequencing result, thereby realizing the Zigbee information channel dynamic selection method based on real-time availability.

A system and method for data collision resolution wherein the same back-off window is sent to a plurality of remote users and is recalculated to maintain a constant collision rate and thereby increase throughput. The collision rate of the network is estimated in the present invention by detecting collisions in reservation slots and the size of the back-off window is adjusted to maintain a collision rate of approximately 1−2 / e.

The invention provides a data de-duplication method for lossless compressed files. The method utilizes a data integrity check code of a compressed file such as a cyclic redundancy check code (CRC check codes) as a file signature (File Signature) to recognize a repeated compressed file. Within the limitation of demands of the collision rate, other file attributes such as file length can be extracted, the file length and the check code serve as a file signature to recognize the repeated file; if the compressed file has no the check code, the check code is extracted through calculation, or a Hash value is calculated out through the Hash algorithm and serves as the file signature to recognize the repeated file. The method can be integrated with the conventional repeated data deleting technique and fills up a technique gap that data de-duplication cannot be performed on the compressed files.

The invention discloses an energy-saving medium access control method in an underwater acoustic network and aims at solving the problems of ultrahigh transmission collision rate and ultrahigh energy consumption of data packets in the underwater acoustic network. The method comprises the following steps, dividing a time shaft into cycle periods with equal lengths and establishing a network topology by initialization to realize the synchronization between nodes under the condition that transmission time delay between the nodes is not known so that various nodes at data sending and receiving stages are in alarm states only in special time to send or receive the data packets and are in rest states in most time; and meanwhile, designing a collision avoidance measure, a new node adding treatment measure and a failure node treatment measure. The method can greatly save the energy consumption of the network, prolongs the service life of the network, can lower the collision rate and can effectively bring the dynamic change of the network topology by the change of the underwater environment or the movement, the damage and the updating of the nodes.

The present invention provides a method of dynamic frequency selection, including acquiring candidate channel information, then determining and balancing a candidate channel level of the selected probability of each candidate channel according to the acquired candidate channel information; updating candidate channel selection probability according to determined candidate channel level; selecting a channel according to the updated candidate channel selection probability. The invention also provides a dynamic frequency selection device, base station and network system. By balancing the selected probability of each available candidate channel, the invention reduces the access collision rate of the adjacent cognitive system in a certain candidate channel, thereby reducing the maximum time relay of the network system, improving the throughput of the network system.

The invention relates to the technical field of distributed databases, and particularly relates to a webpage URL repetition elimination method based on the distributed database. The method comprises the following steps: a step S101: acquiring to-be-crawled URLs, wherein to-be-crawled webpage URLs of a webpage are acquired by distributed crawlers; a step S102: calculating hash values of the URLs; a step S103: inquiring the database, wherein the distributed crawlers compress and uniformly send the URLs in an own collection library to the distributed database for executing repetition elimination; a step S104: feeding back a result, wherein a data query result is returned back; and a step S105: data acquisition, wherein crawler nodes determine whether the webpage can be crawled or not according to the returned result. With the method mentioned above, the webpage URL repetition elimination method based on the distributed database, provided by the invention, solves a memory problem and a single point problem in a massive URL repetition elimination process better, and simultaneously guarantees high query efficiency and low collision rate.

The invention discloses a self-adaptive optimistic concurrency control method, which is substantially applied to a multiple user concurrent environment based on a main memory. The method comprises two concurrency control methods that an optimistic concurrency control is converted into a pessimistic concurrency control and the pessimistic concurrency control is converted into the optimistic concurrency control; when the system is under the environment of high collision rate, a concurrency control policy is converted into the pessimistic concurrency control from the optimistic concurrency control; and when the system is under the environment of low collision rate, the concurrency control policy is converted into the optimistic concurrency control from the pessimistic concurrency control. According to the elf-adaptive optimistic concurrency control method, compared with the pure optimistic concurrency control method or the pessimistic concurrency control method, the defect that the concurrency capability is reduced under the environment of high collision rate or the unlocking of a lock is avoided, and the concurrency capability of the system can be greatly improved.

The invention provides a data retransmission method and device. The method comprises the following step: determining to-be-retransmitted data; and retransmitting the data by using a predetermined retransmission way, wherein the predetermined retransmission way comprises one of the followings: retransmitting the data through a multi-access signature MA signature indicated by a downlink control channel by using the network side, and retransmitting the data through the multi-signature MA signature indicated by the downlink control channel by using a terminal identifier ID and the network side. Through the retransmission method provided by the invention, the problem that the data transmission is high collision rate when the terminal retransmits the data in the related technology is solved, and then the effect of reducing the collision rate of the data retransmission is reduced.

Applicants' Contention-Resolution System for a Command-Response Data Network uses a base unit (base) that detects the occurrence of collisions for the entire network and controls the maximum length of time allowed for the multiple remote units (remotes) in the network before re-trying to send responses to the base. The base either expands or contracts this maximum time delay as needed to accommodate the number of the possible network remotes, depending on the detected collision rate and the overall utilization of the network until the base determines that there are no remotes to be registered or all of the available network slots are filled, whichever occurs first.

The invention belongs to the technical field of special machining devices, and provides a special circumference weld opening / closing machine capable of tracking the welding position automatically. A middle opening / closing box body with an upper box body and a lower box body is mainly adopted for the circumference weld opening / closing machine. An air cylinder supporting base fixed to the lower box body is connected with the lower end of an air cylinder through a pin shaft. An air cylinder connection block is directly connected with a piston rod of the air cylinder and connected with the upper box body through a connection pin shaft. The upper box body is connected with the lower box body through an opening / closing shaft. The upper box body is provided with an adjustment shaft, a blocking shaft and a side jacking shaft. The lower box body is provided with a correction block, a small opening stopping block and an opening / closing gear supported by a supporting wheel, and the two sides of the lower box body is provided with a blocking shaft and a side jacking shaft respectively. A small gear in the middle opening / closing box is meshed with the opening / closing gear through an intermediate gear. According to the circumference weld opening / closing machine, the middle opening / closing box body is designed to be of an opening / closing structure, the part taking process is reduced for operators, the operators can directly take out products from the front, meanwhile the scratching and collision rate of the products is lowered, and working efficiency and product quality are improved.