摘要:
A velocity estimation apparatus and method for a communication system including a transmitter for transmitting signals through wireless channels and a receiver for receiving the signals and restoring data. The apparatus includes a pilot signal detector for detecting a pilot signal from a received signal, a maximum Doppler frequency estimator for estimating a maximum Doppler frequency using the pilot signal detected by the pilot signal detector, and an adaptive type band-limit filter having a limit band based on a previous output value of the maximum Doppler frequency estimator. By using the pilot signal, which is removed with noise, while passing through the band-limit filter, it is possible to precisely estimate a maximum Doppler frequency, and thereby estimate the velocity.
摘要:
Disclosed is a method for estimating the velocity of a mobile station in Rician fading environments in which a direct wave exists. Cellular mobile communication environments include two environments, Rician fading environments in which a direct wave exists and Rayleigh fading environments in which a direct wave does not exist. Generally, many methods for estimating the velocity of a mobile station have been known in Rayleigh fading environments. However, in Rician fading environments in which a direct wave exists, many errors occurs in estimating the velocity of a mobile station due to difficulty in estimation of a Rician coefficient K and an incident angle θ 0 . According to the invention, a method is provided, error is mostly eliminated in estimating the velocity of a mobile station by obtaining a maximum Doppler frequency of the mobile station, even without directly obtaining a Rician coefficient K and an incident angle θ 0 .
摘要:
A user allocating apparatus and method in a multiple antenna mobile communication system supporting multi-user diversity is provided. Each user calculates effective Signal-to-Interference Noise Ratios (SINRs) and bit loading over every possible detection order and selects a detection order maximizing the number of channels with a minimum product of the minimum symbol distance of a modulation scheme and an effective SINR, thereby minimizing an average error probability. A base station receives detection orders from users and selects a user with a maximum detection order value. The base station then transmits data to the selected user using modulation schemes determined by the user for the transmit antennas.
摘要:
A velocity estimation apparatus and method for a communication system including a transmitter for transmitting signals through wireless channels and a receiver for receiving the signals and restoring data. The apparatus includes a pilot signal detector for detecting a pilot signal from a received signal, a maximum Doppler frequency estimator for estimating a maximum Doppler frequency using the pilot signal detected by the pilot signal detector, and an adaptive type band-limit filter having a limit band based on a previous output value of the maximum Doppler frequency estimator. By using the pilot signal, which is removed with noise, while passing through the band-limit filter, it is possible to precisely estimate a maximum Doppler frequency, and thereby estimate the velocity.
摘要:
A synchronization method in an OFDM based communication system. A transmitting side generates and transmits an OFDM symbol having a constant cyclic prefix, independent of time domain data symbols that are to be transmitted. A receiving side estimates a timing synchronization error based on the known cyclic prefix. Because the timing synchronization error is estimated based on the constant cyclic prefix, which is always known, a highly reliable correlation is achieved, thereby improving the accuracy of synchronization.
摘要:
A method is provided for recognizing the frequency bandwidth of a base station in a mobile communication system with frequency bandwidth scalability where the transmission frequency bands of base stations and mobile stations having different frequency bandwidths are overlaid with one another. The base stations transmit to a mobile station first information, including information about their frequency bandwidths at the same frequency position over a minimum frequency bandwidth with the same center frequency. The mobile station recognizes the presence of the base stations by comparing the first information from the base stations and detects the frequency bandwidth information in the first information.
摘要:
A method of constructing a micro- or pico-cells and a virtual macro-cell hierarchical cellular system structure comprising contiguous cells each containing a base station and sectors, wherein a virtual cell comprising three surrounding FDD macro-cell base stations over underlay the TDD micro- or pico-cells. In the proposed TDD/virtual FDD hierarchical cellular structure, a method of locating underlay cells' base station and macro-cells' base station to keep a least interference distance and a method of aligning the TDD micro-or pico-cells' sectors antenna beam direction with the FDD macro-cells' sectors beam direction are proposed, such that this system can suppress the additional inter-system interference and adjacent channel interference. The algorithm of utilising and borrowing the underused FDD macro-cells' resource and the mechanism of deciding the feasible resource borrowing region and smart antenna applicable region is proposed in such a way that the radio network controller and TDD micro- or pico-cell base stations can build up and decide the preference list of which sector, users, and resource to be served, which eventually resulting in the flexible and adaptive radio resource management of the RNC and achieving the optimal utilisation of the overall system resource.
摘要:
A method and apparatus for transmitting and receiving a signal in a wireless communication system. The wireless communication system includes a transmitter with at least four transmit antennas and a receiver with at least one receive antenna. Space Frequency Block Coding (SFBC) processes are performed for input signals on a basis of two antenna pairs. Signal blocks whose number corresponds to the number of transmit antennas are output. A Space Time Block Coding (STBC) process is performed for the signal blocks generated according to the antenna pairs. Signals carried by single carriers are transmitted through the at least four transmit antennas mapped to the signal blocks.
摘要:
Disclosed is a multicarrier-based wireless communication system including a base station for providing a multiple access service to terminals which filter multitone transmitting signals through filters and transmit the filtered signals. A transmitter of the respective terminals includes a multiplexer for multiplexing an input signal and outputting the signal as a plurality of transmitting signals, at least one filter bank for filtering the plurality of transmitting signals, an inverse fast Fourier transformer for executing inverse fast Fourier transform of the filtered transmitting signals output from the filter bank, and a filter information generator for providing filter information to the filter bank. Since the transmitter of the present invention distinguishes users from each other by a filter and thus no synchronization is required between users, which causes a problem in an uplink of the multicarrier-based wireless communication system, system performance can be expected to be improved.