182 results about "Guard time" patented technology

According to one embodiment of the present invention, the method for transmitting control information from a relay node to a base station on a backhaul link comprises the steps of: determining whether one time slot of a backhaul uplink subframe from the relay node to the base station is a first type slot having transmitted symbol with guard time set or a second type slot without guard time set; diffusing the control information in a time domain using a first length sequence for the first type slot or a second length sequence for the second type slot; mapping the diffused control information on at least one slot from the first type slot or the second type slot; and transmitting the backhaul uplink subframe having more than one slot from the first type slot or the second type slot wherein the control information is mapped.

According to one embodiment of the present invention, the method for transmitting control information from a relay node to a base station on a backhaul link comprises the steps of: determining whether one time slot of a backhaul uplink subframe from the relay node to the base station is a first type slot having transmitted symbol with guard time set or a second type slot without guard time set; diffusing the control information in a time domain using a first length sequence for the first type slot or a second length sequence for the second type slot; mapping the diffused control information on at least one slot from the first type slot or the second type slot; and transmitting the backhaul uplink subframe having more than one slot from the first type slot or the second type slot wherein the control information is mapped.

A method of transmitting a signal of a base station in a wireless communication system is provided. The method includes transmitting a first signal to the relay station through the transmission period in a subframe including a transmission period and a guard time for transmission / reception switching of a relay station, and transmitting a second signal to a macro user equipment through the guard time. Accordingly, a signal can be effectively transmitted in the wireless communication system employing the relay station.

A communication system using OFDM transmission from a base station to subscriber units, includes means for achieving a bi-directional channel. These means comprise transmitting means in the subscriber units for the transmission of signal synchronous with the guard time interval in the OFDM transmission, and receiving means in the base station for the reception of the transmitted signals. The system also includes signal shaping means in the receiver of the base station and / or the subscriber unit for the application of a window in time to signals received therein. A communication system includes a combination of CDMA modulation codes and OFDM coding / decoding means to achieve orthogonality between signals from the various users in the uplink. A communication system includes a combination of OFDM and channeling means for achieving orthogonality between signals from the various users in the uplink. Automatic Frequency Control is achieved with means in the mobile unit for achieving a frequency-lock to the base station.

An OFDM system uses a normal mode which has a symbol length T, a guard time TG and a set of N sub-carriers, which are orthogonal over the time T, and one or more fallback modes which have symbol lengths KT and guard times KTG where K is an integer greater than unity. The same set of N sub-carriers is used for the fallback modes as for the normal mode. Since the same set of sub-carriers is used, the overall bandwidth is substantially constant, so alias filtering does not need to be adaptive. The Fourier transform operations are the same as for the normal mode. Thus fallback modes are provided with little hardware cost. In the fallback modes the increased guard time provides better delay spread tolerance and the increased symbol length provides improved signal to noise performance, and thus increased range, at the cost of reduced data rate.

A method of transmitting a reference signal performed by a Relay Station (RS) in a wireless communication system comprises allocating a guard time in the front of a backhaul subframe or the end of the backhaul subframe, the backhaul subframe comprising a plurality of slots, each of the plurality of slots comprising a plurality of Orthogonal Frequency Division Multiplexing (OFDM) symbols, and the guard time being a time interval for switching between an access link and a backhaul link, and transmitting a Demodulation Reference Signal (DMRS) to a Base Station (BS) in an OFDM symbol of the backhaul subframe. The OFDM symbol for the DMRS is not over-lapped with the guard time.

A MANET may include a plurality of MANET nodes each including a wireless transceiver, a position determining device, and a controller cooperating with the wireless transceiver and position determining device for establishing a wireless communication link with an adjacent MANET node based upon a time division multiple access (TDMA) implementation. The TDMA implementation may use time slots without using a range dependent guard time therein. The controller may further determine a range to the adjacent MANET node, and schedule time slots to offset a link delay in a received signal from the adjacent MANET node based upon the determined range.

A method operates at the data link level. Each bridge associates, during a guard time, the port through which a frame is first received with a source MAC address until a unicast reply frame confirms the matching two-way path between the source and destination addresses. Any frame from the same source received through another different port is discarded. Each bridge forwards the received broadcast frames through the rest of the ports, except those involving prohibited (down-up) turns, and deviates (or optionally returns) the unicast frames with an unknown or aged destination address through the spanning tree. The protocol can operate with encapsulation in the border bridges or without encapsulation, using in this case the replacement of universal MAC addresses in the border bridges with local MAC addresses. The establishment and control of paths can optionally be performed proactively by the border bridges, especially the bridges connected to servers.

A device and a method within a communications system where at least some part of the transmission is executed by means of radio waves, and where symbols are transmitted by means of Orthogonal Frequency Divisional Multiplexing, so called OFDM-technology, between a transmitting unit and a receiving unit, at which the symbol transmission is executed over a transmission channel in blocks of binary digits with a guard interval GI between said blocks, where transmitting unit is equipped with means to control the length of the guard interval (GI) with regard to the physical conditions for / of the transmission channel, so that the guard interval can be reduced without the disturbance susceptibility being increased, but instead increasing the capacity / throughput of the transmission channel by the time that is set free / made available being used to transmit information. One embodiment of the invention includes a guard interval adjustment unit connected to other OFDM-equipment in transmitting and / or receiving unit.

In one embodiment, the present invention includes a repeating frame for a time division radio communications system with a sequence of uplink slots each having a predetermined duration, a sequence of downlink slots, each having a predetermined duration that is greater than the duration of the uplink slots, an interburst guard time between each uplink slot, an interburst guard time between each downlink slot, and an interframe guard time after the sequence of downlink slots.

At a master controller of a space switch in a node in a data network, a request is received from a source node that requests a connection to be established through the space switch. This request is compared to other such requests so that a schedule may be established for access to the space switch. The schedule is then sent to the source nodes as well as to a slave controller of the space switch. The source nodes send data bursts which are received at the space switch during a short guard time between successive reconfigurations of the space switch. Data bursts are received at the space switch at a precisely determined instant of time that ensures that the space switch has already reconfigured to provide requested paths for the individual bursts. The scheduling is pipelined and performed in a manner that attempts to reduce mismatch intervals of the occupancy states of input and output ports of the space switch. The method thus allows efficient utilization of the data network resources while ensuring virtually no data loss.

A technique for scheduling transmissions for a plurality of transmitters in a TDMA network is described. The technique includes assigning guard time between each pair of successive transmitters, where the guard time is related to the propagation delay between the pair of successive transmitters. Total guard time is minimized by selecting an order of transmission for the plurality of transmitters to minimize the total guard time.

A method and system are disclosed that improve the efficiency of a time division duplex communication system. The uplink transmission slots of a plurality of mobile stations are arranged in an order so as to take advantage of the short propagation delay to the closest mobile stations, thereby advantageously resulting in a time division duplex guard time which is potentially independent of cell size.

A portable terminal communicates with a plurality of base stations by use of an OFDM signal. The portable terminal includes a communication unit sending and receiving the OFDM signal to and from the base stations, a switching timing detector, and an OFDM signal controller. The switching timing detector detects switching timing at which handover and a normal state are switched therebetween. The OFDM signal controller changes a guard time length of the OFDM signal upon detecting the timing by the switching timing detector.

Disclosed is a system and method for optimizing capacity in a multi-user time division duplex (“TDD”) communication system such as a broadband wireless radio frequency communication system. More specifically the invention minimizes guard time in duplexed signals to thereby allow for higher data throughput which results in an increase in system communication capacity. Depending upon instantaneous traffic load associated with the subscribers using a particular TDD carrier, guard times may be adjusted to provide a desired level of throughput. As traffic loads demand, the order of assignment of burst periods in either or both the transmit and receive frames of a TDD carrier with respect to the subscriber systems operable thereon are adjusted to accommodate desired guard times.

The present invention relates to a method for a repeater to transmit and receive a signal on a downlink sub frame in a wireless communication system, comprising the steps of: transmitting a first physical downlink control channel (PDCCH) to terminals positioned within a repeater cell on a downlink sub frame; and receiving a second PDCCH or a physical downlink shared channel (PDSCH) from a base station after a first guard time succeeding a first PDCCH section elapses, wherein a second guard time succeeding the PDSCH or the second PDCCH received from the base station is allocated to the downlink sub frame, and the repeater receives the second PDCCH through a certain range of symbols in accordance with information on the predetermined control channel section, which is received from the base station.

A method and system of background scanning of an evaluated system by a mobile station without missing paging frames on a registered system. The registered system is defined as the system in which the mobile station has registered and will receive pages. The evaluated system is the system from which the mobile station must retrieve parameters (the possibly higher priority system). The various disclosed embodiments use the periodicity of the paging information to set a guard timer that will force the system back to the registered system before the paging information in the next time slot is missed. After receiving the paging information, the mobile station can continue its search and evaluation of base systems. In other words, the guard timer breaks the background scan into smaller segments that are performed between retrievals of paging information.

A wireless communication system is disclosed. A method for constructing a RACH preamble according to a cell radius of a base station (BS) irrespective of a guard time (GT) and a method for allocating the RACH preamble are disclosed. A method for constructing a preamble of a random access channel (RACH) includes acquiring time-length information of a predetermined cyclic prefix (CP) for each cell radius of a base station (BS), acquiring sequence time-length information of a single sequence or a repeated sequence, and constructing the preamble using the predetermined CP time-length information and the sequence time-length information, irrespective of a time length of a guard time (GT).

The present invention aims to perform sensing of a frequency with high accuracy by securing a sufficient amount of time to measure a reception level of a guard time while avoiding a decrease in transmission rate as much as possible even when the distance between a terminal and a base station is short. To this end, a base station is disclosed which is configured to set a guard time based on the measured reception level of a UL signal during a period other than a period when it is time to measure an interference amount. Meanwhile, the base station sets a guard time so as to secure a predetermined length required for measurement of a reception level when it is time to measure the interference amount.

The invention discloses a sending method of terminal front in a time division duplexing system. An RACH channel only requires less guard time to reach the coverage area of the RACH channel. The method comprises the following steps: firstly, when a system is configured, determining the total guard time TGT of the random access RACH channel, and dividing a cell into a plurality of circular or annular areas according to the distance between the cell and a base station; secondly, when the front is sent by a terminal, judging the area of the terminal, and determining the front sending time corresponding to the area; and thirdly, sending the front by using the terminal at the determined sending time. By adopting the method, the method for sending the starting point of a preamble at a terminal side is determined according to the position range of the terminal in the cell; and the larger coverage area can be supported under the condition that the total length of the guard time is definite without estimating the distance between the range and the base station accurately.

A technique capable of improving the communication throughput while maintaining the interchangeability with a radio communication system or radio communication method employing carrier sense in a conventional multiple access system is disclosed and, on the basis of this technique, a radio communication terminal accommodating apparatus determines the allocation order of communication right permitting the occupation of a radio transmission medium with respect to each of a plurality of radio transmission terminals and transmits a multiple-polling signal 311 including information on this order to the plurality of radio communication terminals at an arbitrary transmission timing acquired through the carrier sense. Thus, each of communication right time periods (communication right time periods 312 to 314) for which the occupation of the radio transmission medium is permissible is allocated to each of the plurality of radio communication terminals. In addition, a time sufficiently shorter than a guard time (carrier sense time) in a conventional system is employed as a time interval between communication right time periods adjacent to each other.

Disclosed is an inventive system and method for extracting signal energy from the guard time portion of a communication frame based on the amount of multipath interference experienced by that communication frame. In one embodiment, N blocks of samples are created from the received frame wherein the samples in the guard time portion of the received frame are included in one of more of the N blocks of samples. The estimated symbols, or estimated bits, determined from the received samples are checked for corruption due to multipath interference. For those blocks for which multipath interference is not detected, the estimated symbols, or estimated bits, are coherently added together so as to take advantage of uncorrupted signal energy from the guard time portion of the frame.

Provided is a method of preventing a data collision that occurs when two or more child nodes simultaneously transmit data to a parent node in a ZigBee network having a tree routing scheme and operating in a beacon mode. In the ZigBee system having the tree routing scheme and operating in the beacon mode, data communication to the parent node is performed in a beacon frame of the parent node. Here, when several child nodes exist under a single parent node, the child nodes transmit data to the parent node at the moment of receiving the beacon of the parent node, so that the data collision may occur when the child nodes simultaneously transmit the data to the parent node in the beacon frame of the parent node. In the method of preventing a data collision, each of the two or more child nodes is set to wait for its guard time (delay time) when transmitting data to the parent node to induce a normal slotted carrier sense multiple access with collision avoidance (CSMA-CA) operation. Therefore, the data collision can be prevented.

A method of transmitting a signal of a mobile station that performs communication with a plurality of cells in a wireless communication system comprises transmitting a control signal or a data signal through an asynchronous channel to a neighboring cell which is not synchronized with the mobile station, the asynchronous channel including cyclic prefix and guard time.

Method for processing hard handoff to prevent unnecessary frequent hard handoffs using specific parameters after the first handoff is performed. The method includes the steps of establishing a Guard-Time period during which handoff is not performed when a mobile station moves slowly in an area in which the cell coverages of the serving and target base stations are overlapped; and establishing a Guard-Level value so that handoff is performed independent of the Guard-Time if the strength of the radio wave for the moving mobile station is less than the Guard-Level during said Guard-Time. The Guard Time period prevents hard handoff even when a base station controller receives a request for handoff based on information received from the moving mobile station. Although the base station controller prevents the hard handoff dependent on the Guard-Time, the base station controller permits soft handoff and softer handoff to occur normally. The Guard-Time and Guard-Level are set up according to the base station, the base station controller and the characteristics of the coverage area. The Guard-Time is set up by a system-operator and the Guard-Level is used in relation with the value of T-DROP.

The invention discloses a control method for pulling an arm bushing out of a crane single cylinder bolt system. The control method comprises the following steps of (11) presetting the release guard time of a cylinder bolt; (12) releasing the cylinder bolt, and recording the actual release time of the cylinder bolt; (13) judging whether the actual release time of the cylinder bolt achieves the preset release guard time, if so, going to step (14), if not, going on step (13); and (14) giving response to an arm pin pulling order input from the external world so as to pull the arm pin out. According to the control method, the premise that the arm pin pulling order is carried out is that the cylinder bolt is released for enough long time, namely, under the premise that the cylinder bolt is completely released, the arm pin is pulled, therefore, the phenomenon that the arm pin and the cylinder bolt are locked as an operator inputs the arm pin pulling order too fast is avoided, and the crane is ensured to work normally.

The invention provides a method and an apparatus for monitoring subframes in a communication system. The method comprises: sending a message used for indicating configuration of the subframes to a user terminal by a base station; according to the message used for indicating the configuration of the subframes, determining types of the subframes in a radio frame by the user terminal; further configuring determined dynamic subframes. In the method for monitoring subframes in the communication system, the types of the subframes such as a fixed upstream subframe, a fixed downstream subframe, special subframe, etc. are determined and obtained according to the message used for indicating the configuration of the subframes. The method realizes good compatibility with an LTE terminal of an older version and reduces guard time required for changes of the subframe types. In addition, through adding the dynamic subframe type, dynamic change needs of an upstream business volume and a downstream business volume are preferably satisfied, use efficiency of resources is improved. Meanwhile, the method is easy to realize, and cost of redevelopment is reduced.

A radio transmitting apparatus and a radio transmitting method wherein the increase of the guard time in a random access region is reduced to secure the data transmitting region of an upstream line. In this apparatus, when a received signal power estimated by a received signal power estimating part (205) is the higher, a RACH format selecting part (206) selects a RACH format having the longer frame length. Contrarily, when a received signal power estimated by the received signal power estimating part (205) is the lower, the RACH format selecting part (206) selects a RACH format having the shorter frame length. A RACH data part arranging part (207) appropriately selects, in accordance with the selected RACH format, top-priority information, such as terminal identifiers, priority information, such as connection request information or band assignment request information, and non-priority information and arranges RACH data parts.

The invention relates to a conflict-free transmission method of a sensor network, which comprises the following steps that: the working period of a coordinator is divided into a time slot sequence which consists of continuous time slots, the time slots in the time slot sequence are numbered and a number sequence which consists of the numbers of the time slots is periodic; the coordinator which works in the time slots in the time slot sequence is virtualized to be virtual coordinators corresponding to the time slots and the time slots with the same number correspond to the same virtual coordinator; general nodes connect with the virtual coordinators; the general nodes send guard time slot allocation requests to the virtual coordinators; the virtual coordinators transmit reply information to the general nodes according to the guard time slot allocation requests; and the general nodes transmit data to the virtual coordinators according to the reply information. By adopting the conflict-free transmission method of the sensor network, the transmission efficiency can be effectively improved.

An OFDM system uses a normal mode which has a symbol length T, a guard time TG and a set of N sub-carriers, which are orthogonal over the time T, and one or more fallback modes which have symbol lengths KT and guard times KTG where K is an integer greater than unity. The same set of N sub-carriers is used for the fallback modes as for the normal mode. Since the same set of sub-carriers is used, the overall bandwidth is substantially constant, so alias filtering does not need to be adaptive. The Fourier transform operations are the same as for the normal mode. Thus fallback modes are provided with little hardware cost. In the fallback modes the increased guard time provides better delay spread tolerance and the increased symbol length provides improved signal to noise performance, and thus increased range, at the cost of reduced data rate.