Beyond 3G (B3G) system, the future mobile communication system, is envisioned as a user-centric, open, and convergent information infrastructure capable of providing personalized services. It is extremely important to...Beyond 3G (B3G) system, the future mobile communication system, is envisioned as a user-centric, open, and convergent information infrastructure capable of providing personalized services. It is extremely important to develop service models and architectures for B3G system. A three-dimension service model is proposed. The dimensions are identified as service support scope, service capability definition, and adaptive feature elements. Then, the hierarchical service architecture for B3G is introduced. The enabling technologies for B3G service architecture are discussed in this paper, such as Virtual Home Environment (VHE), service support environment, service openness, distributed computing, intelligent technology, and profile.展开更多
The dilemma of modern mobile communications technology is analyzed. Aiming at some problems in the 3G systems, a new network architecture is proposed on the principle of mobile information sharing grid (MIS-Grid). The...The dilemma of modern mobile communications technology is analyzed. Aiming at some problems in the 3G systems, a new network architecture is proposed on the principle of mobile information sharing grid (MIS-Grid). The essence of MIS-Grid is to transfer the hot wide band information with cheap unidirectional broadcasting channels and the personalized services with relatively expensive interactive networks.展开更多
Multi-Input Multi-Output antennas based Orthogonal Frequency-Division Multiplexing （MIMO-OFDM） has been chosen as the air interface technology for China＇s beyond 3G Time-Division Duplex （TDD） mobile system in the...Multi-Input Multi-Output antennas based Orthogonal Frequency-Division Multiplexing （MIMO-OFDM） has been chosen as the air interface technology for China＇s beyond 3G Time-Division Duplex （TDD） mobile system in the FUTURE research project. Channel estimation plays a key role on the performance of the MIMO-OFDM receiver. In this paper, we present five channel estimation algorithms and study their performance in a simulated beyond 3G TDD mobile system, Simulation results show that the adaptive 2D-LMS algorithm we proposed recently has the best performance when the signal to noise ratio is lower than 8 dB.展开更多
An outdoor propagation measurement campaign for beyond 3G （B3G） as well as a wide-band indoor measurement campaign have been performed recently in Beijing, China, in which the sounding signals are transmitted by an ...An outdoor propagation measurement campaign for beyond 3G （B3G） as well as a wide-band indoor measurement campaign have been performed recently in Beijing, China, in which the sounding signals are transmitted by an one-antenna base station and received by a two-antenna mobile receiver operated at 3.49～3.51 GHz bandwidth. Different scenarios： stationary line-of-sight （LoS）, stationary non-LoS （NLoS） scenarios, and dynamic NLoS are deliberately chosen in a classic urban environment and office environment. The initial results are presented in this article. Parameters including vector channel impulse response, path loss, rays number, excess delay spread etc. are extracted, analyzed, and briefly reported here.展开更多
Automatic gain control（AGC） has an important role in multi-input multi-output-orthogonal frequency-division multiplexing （MIMO-FDM） system, especially, when receiving antennas are distributed. In recent years, muc...Automatic gain control（AGC） has an important role in multi-input multi-output-orthogonal frequency-division multiplexing （MIMO-FDM） system, especially, when receiving antennas are distributed. In recent years, much work has been done on efficiency and simplification of AGC, but few of them are aiming at multiple antennas. This article, on the assumption of ideal AGC for single receiving antenna, analyzes feasible AGC methods for MIMO system from a new aspect, then brings forward three applicable AGC methods： separate automatic gain control, joint automatic gain control, and partly-joint automatic gain control （PJ-AGC）. After simulation, when parameters are properly set, PJ-AGC has the best performance and can be applied to B3G MIMO-OFDM system.展开更多
In this paper, adaptive modulation with channel estimation in high-speed packet-based Orthogonal Frequency Division Multiplexing (OFDM) communication systems for beyond 3G are discussed. Different adaptive modulation ...In this paper, adaptive modulation with channel estimation in high-speed packet-based Orthogonal Frequency Division Multiplexing (OFDM) communication systems for beyond 3G are discussed. Different adaptive modulation and channel estimation methods are presented and compared, then those methods suitable for our intended application are chosen. Conclusions can be drawn from computer simulations that with proper selection of packet length and subband width, wide subband adaptive modulation with Least Square plus Discrete-time Fourier Transform (LS-DFT) channel estimation can give an acceptable performance with low complexity for channel with low Doppler shift and small path delay. Otherwise, narrow subband or subcarrier adaptive modulation together with LS-DFT plus Decision Directed (LS-DFT-DD) must be used.展开更多
基金Project ofNational "863" Plan of China (No.2004AA119030)
文摘Beyond 3G (B3G) system, the future mobile communication system, is envisioned as a user-centric, open, and convergent information infrastructure capable of providing personalized services. It is extremely important to develop service models and architectures for B3G system. A three-dimension service model is proposed. The dimensions are identified as service support scope, service capability definition, and adaptive feature elements. Then, the hierarchical service architecture for B3G is introduced. The enabling technologies for B3G service architecture are discussed in this paper, such as Virtual Home Environment (VHE), service support environment, service openness, distributed computing, intelligent technology, and profile.
基金Supported by the Foundation of National 863 Programme of China (No.2002AA121063) and the National Natural Science Foundation of China (No.60272014)
文摘The dilemma of modern mobile communications technology is analyzed. Aiming at some problems in the 3G systems, a new network architecture is proposed on the principle of mobile information sharing grid (MIS-Grid). The essence of MIS-Grid is to transfer the hot wide band information with cheap unidirectional broadcasting channels and the personalized services with relatively expensive interactive networks.
基金This workis supported by China National"863"Project (2003AA12331004) , National Natural Science Foundation of China (60472070) .
文摘Multi-Input Multi-Output antennas based Orthogonal Frequency-Division Multiplexing （MIMO-OFDM） has been chosen as the air interface technology for China＇s beyond 3G Time-Division Duplex （TDD） mobile system in the FUTURE research project. Channel estimation plays a key role on the performance of the MIMO-OFDM receiver. In this paper, we present five channel estimation algorithms and study their performance in a simulated beyond 3G TDD mobile system, Simulation results show that the adaptive 2D-LMS algorithm we proposed recently has the best performance when the signal to noise ratio is lower than 8 dB.
文摘An outdoor propagation measurement campaign for beyond 3G （B3G） as well as a wide-band indoor measurement campaign have been performed recently in Beijing, China, in which the sounding signals are transmitted by an one-antenna base station and received by a two-antenna mobile receiver operated at 3.49～3.51 GHz bandwidth. Different scenarios： stationary line-of-sight （LoS）, stationary non-LoS （NLoS） scenarios, and dynamic NLoS are deliberately chosen in a classic urban environment and office environment. The initial results are presented in this article. Parameters including vector channel impulse response, path loss, rays number, excess delay spread etc. are extracted, analyzed, and briefly reported here.
文摘Automatic gain control（AGC） has an important role in multi-input multi-output-orthogonal frequency-division multiplexing （MIMO-FDM） system, especially, when receiving antennas are distributed. In recent years, much work has been done on efficiency and simplification of AGC, but few of them are aiming at multiple antennas. This article, on the assumption of ideal AGC for single receiving antenna, analyzes feasible AGC methods for MIMO system from a new aspect, then brings forward three applicable AGC methods： separate automatic gain control, joint automatic gain control, and partly-joint automatic gain control （PJ-AGC）. After simulation, when parameters are properly set, PJ-AGC has the best performance and can be applied to B3G MIMO-OFDM system.
文摘In this paper, adaptive modulation with channel estimation in high-speed packet-based Orthogonal Frequency Division Multiplexing (OFDM) communication systems for beyond 3G are discussed. Different adaptive modulation and channel estimation methods are presented and compared, then those methods suitable for our intended application are chosen. Conclusions can be drawn from computer simulations that with proper selection of packet length and subband width, wide subband adaptive modulation with Least Square plus Discrete-time Fourier Transform (LS-DFT) channel estimation can give an acceptable performance with low complexity for channel with low Doppler shift and small path delay. Otherwise, narrow subband or subcarrier adaptive modulation together with LS-DFT plus Decision Directed (LS-DFT-DD) must be used.
