摘要:
Provided is a method of forming a random access preamble structure for an extended cell radius in a cellular system, the method including: generating a cyclic prefix (CP), which is the sum of a maximum delay spread and the maximum round trip delay according to the extended cell; generating a preamble sequence part. The method is used to form a preamble structure for an extended cell radius from among random access preamble structures transmitted when initial synchronization is achieved, when synchronization is lost, or when a handover is performed, during a random access process of the cellular system.
摘要:
Provided is a method of forming a random access preamble structure for an extended cell radius in a cellular system, the method including: generating a cyclic prefix (CP), which is the sum of a maximum delay spread and the maximum round trip delay according to the extended cell; generating a preamble sequence part. The method is used to form a preamble structure for an extended cell radius from among random access preamble structures transmitted when initial synchronization is achieved, when synchronization is lost, or when a handover is performed, during a random access process of the cellular system.
摘要:
The present invention relates to a packet data transmission method in an OFDMA system and an apparatus thereof. The present invention provides a user packet data transmission method including generating a RACH burst for channel information estimation, selecting a first antenna among a plurality of antennas, transmitting the RACH burst through the first antenna to a base station, receiving a data transmission acceptance signal from the base station, in response to the RACH burst, transmitting user packet data through the first antenna when receiving a signal indicating that the data transmission is allowed, and selecting a second antenna that is difference from the first antenna and transmitting a RACH burst through the second antenna when receiving a signal indicating that the data transmission is not allowed, and a transmitting apparatus of a mobile station having the plurality of antennas. According to the present invention, the RACH burst and user packet data are transmitted by using a mobile station having a plurality of antennas in an LTE-applied OFDMA system, and therefore data transmission can be performed with a wide bandwidth and high data rate and a deep fading period that may occur during the data transmission can be reduced, thereby preventing call dropping and improving data transmission performance.
摘要:
Provided are a receiver and a receiving method for a scalable bandwidth in a mobile station of an Orthogonal Frequency Division Multiplexing (OFDM) system. The receiving method includes the steps of: (a) filtering a received RF signal; (b) oscillating a frequency according to a center frequency control signal to output a local oscillation frequency; (c) down-converting the filtered RF signal by using the local oscillation frequency; (d) scalable-filtering the down-converted signal while adjusting a bandwidth according to a bandwidth control signal; (e) controlling gain of the scalable-filtered signal; (f) converting the gain-controlled analog signal into a digital signal by using a sampling frequency matching with a corresponding bandwidth according to an ADC control signal; and (g) demodulating the converted digital signal, outputting the center frequency control signal, the bandwidth control signal, and the ADC control signal according to control information received from an upper layer.
摘要:
Provided are a receiver and a receiving method for a scalable bandwidth in a mobile station of an Orthogonal Frequency Division Multiplexing (OFDM) system. The receiving method includes the steps of: (a) filtering a received RF signal; (b) oscillating a frequency according to a center frequency control signal to output a local oscillation frequency; (c) down-converting the filtered RF signal by using the local oscillation frequency; (d) scalable-filtering the down-converted signal while adjusting a bandwidth according to a bandwidth control signal; (e) controlling gain of the scalable-filtered signal; (f) converting the gain-controlled analog signal into a digital signal by using a sampling frequency matching with a corresponding bandwidth according to an ADC control signal; and (g) demodulating the converted digital signal, outputting the center frequency control signal, the bandwidth control signal, and the ADC control signal according to control information received from an upper layer.
摘要:
The present invention relates to a method for demodulating a BCH by using an SCH in an OFDM system with transmit diversity, and a transmitting apparatus and a receiving apparatus using the same. For this purpose, the present invention provides a transmit diversity transmission method for a transmitting apparatus of a base station that generates an SCH symbol and a BCH symbol, maps the SCH symbol and the BCH symbol to an OFDM signal, converts the OFDM signal into a time domain signal, and transmits the OFDM signal trough a selected antenna among a plurality of antennas. In addition, the present invention provides a method for demodulating a BCH by using an SCH to a mobile station that receives an OFDM signal from the base station, filters an SCH and a BCH from the OFDM signal, converts the OFDM signal to a frequency domain signal, calculates a channel estimation value by using the SCH and the BCH, and coherently demodulates the BCH. According to the present invention, coherent demodulation of a BCH can reduce a frame error generation probability, minimize a channel estimation error due to fading, reduce time for checking the number of antennas of the base station and time for demodulating the BCH, and reduce power consumption.
摘要:
Provided are a reception apparatus and transmission apparatus for supporting a scalable bandwidth in a carrier aggregation environment. The reception apparatus and transmission apparatus can link carrier aggregation technology and scalable bandwidth technology by supporting a scalable bandwidth having different bandwidths in size in a carrier aggregation environment, thereby enhancing compatibility between different wireless communication systems.
摘要:
A back side of a paper is protected from contamination during an operation of the electrophotographic printer. A light scanning unit is warmed up as the main motor operates. This should minimize the potential difference on the surface of the photosensitive drum. A zero or a less than zero voltage is applied to its transfer roller to prevent the toner from adhering to the transfer roller before a paper reaches the transfer roller. This protects the back side of the paper from contamination due to the toner.
摘要:
An image forming apparatus having a multiuser identification printing method for printing user identification data on a printout, the image forming apparatus being shared by plural users wherein the image forming apparatus receives data to be printed through an interface thereof, checks whether a print command is received, and when the print command is received, obtains user identification data, which is stored in an external data input device, from the external data input device that has transmitted the data, and prints the received data together with user identification data.