3178 results about "Preamble" patented technology

A wireless communication system, relay station device, and base station device reduce dead zones in which communication with the base station device is not possible, and enable expansion of service areas. The BS transmits to the RS burst packets and MAP messages including information providing notification of the timing of information transmission and reception. The RS receives the MAP messages and burst packets. The RS stores, in the Preamble Present bits in MAP messages, information providing notification of the preamble transmission timing to control synchronization of reception by the SSs, and transmits the MAP messages to the SSs. The RS transmits burst packets to which preambles are appended to the SSs.

The present invention provides a preamble that is inserted into an OFDMA frame and has a common sequence for all the base stations participating in a transmission. The subscriber station performs fine synchronization using the common sequence on the common preamble, and the resulting peaks will provide the locations of candidate base stations. The base station specific search is then performed in the vicinities of those peaks by using base station specific pseudo-noise sequences. With this two stage cell search, the searching window is drastically reduced. The preamble is matched to known values by a respective receiver to decode the signals and permit multiple signals to be transferred from the transmitter to the receiver. The preamble may comprise two parts, Preamble-1 and Preamble-2, which may be used in different systems, including multioutput, multi-input (MIMO) systems.

The present invention relates to Random Access Channel (RACH) access apparatus for mobile satellite communication system and method therefor. The method for accessing random access channel (RACH) on satellite system, random access channel (RACH) carrying message from a plurality of mobile stations to the satellite system, the method includes the steps of: receiving preamble and the message, the message successively transmitted with the preamble from the plurality of mobile stations; and transmitting acquisition response signal corresponding to the preamble or the message to the plurality of mobile stations. Accordingly, success of packet reception of satellite system is improved and transmission delay is reduced.

A method includes transmitting a random access preamble, receiving a random access response as a response of the random access preamble, wherein the random access response comprises an uplink resource assignment and a request for transmission of a Channel Quality Indicator (CQI), and transmitting the CQI in the uplink resource assignment.

A wireless local area network (WLAN) radio-frequency identification (RFID) tag system provides location finding in a wireless local area network (WLAN), using a WLAN channel. Interference with the WLAN is prevented by either using a sniffer circuit to determine that no network transmission is in progress, using a modified coding sequence or preamble to cause standard WLAN receivers to ignore the RFID tag transmissions, or transmitting a message using a standard WLAN signal addressed to an address not corresponding to a unit within the WLAN. Location units (LUs) and a master unit (MU) within the WLAN receive the RFID tag transmissions and can determine the location of a tag by triangulation based on differences between the signals received at the location units from the tag. The master unit receives the signal information from the location units and computes the location of the tag. Time-difference-of-Arrival (TDOA), received signal strength indication (RSSI) or other triangulation techniques may be used.

Methods and apparatus are provided for communicating data in a multiple antenna communication system having N transmit antennas. According to one aspect of the invention, a header format includes a legacy preamble having at least one legacy long training field and an extended portion having at least N additional long training fields on each of the N transmit antennas. The N additional long training fields may be tone interleaved across the N transmit antennas and are used for MIMO channel estimation. The extended portion may include a short training field for power estimation. The short training field may be tone interleaved across the N transmit antennas and have an extended duration to support beam steering.

Methods and apparatus are provided for improved long preamble formats in a multiple antenna communication system having N antennas. According to one aspect of the invention, a preamble having a legacy portion and a high throughput portion is transmitted (or received) on each of the N transmit antennas, wherein the legacy portion comprises a legacy long training field and the high throughput portion comprises at least N high throughput long training fields, wherein the N high throughput long training fields are transmitted in N time slots using an N×N orthogonal matrix. The orthogonal matrix can be, for example, one or more of a Walsh matrix and a Fourier matrix. The N time slots can optionally comprise a single symbol.

A method for performing a random access in a multi-carrier system includes transmitting a random access preamble on an uplink component carrier to a base station, and receiving a random access response on a first downlink component carrier. The random access response includes information regarding a second downlink component carrier used to transmit a contention resolution message indicating that a random access collision with other mobile stations are resolved. A base station to perform the method includes a preamble reception unit to receive the random access preamble, a response generation unit to generate the random access response, and a response transmission unit to transmit the random access response. A mobile station to perform the method includes a preamble transmission unit, a response reception unit, a carrier configuration unit, and a message reception unit.

Aspects of the invention are directed to physical layer and data link layer signaling in digital video broadcast preamble symbols. Embodiments are directed to distributing physical layer pre-signalling data among preamble symbols. If physical layer data is larger than a predetermined number of preamble symbols, then excess physical layer data is written to data symbols immediately following the preamble symbols in top-down order symbol by symbol or the predetermined number of preamble symbols is increased. If physical layer data is not larger than the predetermined number of preamble symbols such that there is excess preamble symbol space, physical layer pipe 0 data comprising link layer signaling and notification data is carried in the excess preamble symbols or the excess preamble symbols are left empty. Different permutation rules may be used to frequency interleave odd-numbered versus even-numbered orthogonal frequency division multiplexing symbols.

Pilot, preamble and midamble patterns are provided that are particularly suited for four transmit antenna OFDM systems. Pilots are inserted in a scattered manner for each of the four antennas, either uncoded, space-time coded in pairs, space-time frequency coded in pairs, or space-time-frequency coded.

A method and apparatus for handover in a wireless communication system. A handover indication can be received from a source base station (120) that is connected with a mobile station (110). The handover indication can include a random access channel preamble. The random access channel preamble can include a temporary mobile equipment identifier. The random access channel preamble can be received from the mobile station. A timing advance message can be sent in response to receiving random access channel preamble. The timing advance message can be addressed by the random access channel preamble and a source base station identifier. The connection with the mobile station can be switched from the source base station to a target base station (130).

An implantable medical device (IMD) includes a telemetry module to communicate with an external device according to a given protocol. To establish a communication session, the IMD will extend active periods of reception on a given channel when some confirmed data is received from the external device. In addition, once a session has been opened, the programmer transmits a short data set (or preamble) for each cycle which the IMD is set to receive. This data set indicates whether additional data will or will not be sent. If no additional data is to be sent during that cycle, then the IMD powers down the receiver for that cycle.

A wireless local area network (WLAN) radio-frequency identification (RFID) tag system provides location finding in a wireless local area network (WLAN), using a WLAN channel. Interference with the WLAN is prevented by either using a sniffer circuit to determine that no network transmission is in progress, using a modified coding sequence or preamble to cause standard WLAN receivers to ignore the RFID tag transmissions, or transmitting a message using a standard WLAN signal addressed to an address not corresponding to a unit within the WLAN. Location units (LUs) and a master unit (MU) within the WLAN receive the RFID tag transmissions and can determine the location of a tag by triangulation based on differences between the signals received at the location units from the tag. The master unit receives the signal information from the location units and computes the location of the tag. Time-difference-of-Arrival (TDOA), received signal strength indication (RSSI) or other triangulation techniques may be used.

This specification relates to an apparatus and method for performing random access in a wireless communication system. This specification discloses a mobile station, including a reception unit for receiving TAG configuration information on which at least one serving cell configured in the mobile station is classified as a Timing Alignment Group (TAG) from a base station and a transmission unit for transmitting a random access preamble to the base station on one representative serving cell within the TAG. In accordance with this specification, a procedure of obtaining a TAV for a serving cell in order to secure and maintain uplink timing synchronization becomes clear, the time taken to obtain uplink synchronization for a serving cell may be reduced, and overhead due to excessive random access attempts may be reduced by obtaining a TAV for a plurality of serving cells through one random access procedure.

A disk drive has a spindle motor, a disk mounted for rotation on the spindle motor, and a head for reading from and writing to the disk. The disk includes a recording surface having a track that includes a first full servo wedge and a second full servo wedge, each of the first full and second full servo wedges defining a leading end and a trailing end and having, between leading and trailing ends, a preamble, a servo sync word, a track ID, and a plurality of servo positioning burst fields. The recording surface further includes user addressable data locations and a first partial servo wedge disposed between the trailing end of the first full servo wedge and the leading end of the second full servo wedge. The first partial servo wedge is devoid of preamble, track ID and wedge ID and includes a short servo sync mark that is different from the servo sync word. The servo sync mark defines a predetermined bit pattern that is immediately followed by a plurality of servo bursts.

An advanced memory having improved performance, reduced power and increased reliability. A memory device includes a memory array, a receiver for receiving a command and associated data, error control coding circuitry for performing error control checking on the received command, and data masking circuitry for preventing the associated data from being written to the memory array in response to the error control coding circuitry detecting an error in the received command. Another memory device includes a programmable preamble. Another memory device includes a fast exit self-refresh mode. Another memory device includes auto refresh function that is controlled by the characteristic device. Another memory device includes an auto refresh function that is controlled by a characteristic of the memory device.

A low power device is presented. In some embodiments, the low power device communicates with other devices utilizing transport channels defined from combinations of a plurality of physical channels. In some embodiments, the low power device communicates with other devices utilizing packets that includes a preamble, a header with a sync and frame info, and a frame. The frame, for example, can be a wake-up frame, a request frame, a response frame, or one or more data frames. In some embodiments, the wake-up frame can include a count-down integer indicating the number of wake-up frames before a request frame is sent. In some embodiments, arbitration may be utilized between devices responding to a request. In some embodiments, specific requests commands can be included in the request frame and corresponding response frames are responsive to the commands.