The compensation method aiming to reduce the irradiation on the user＇s body and to form a weak field area （a dark spot） in an antenna near region is considered. The results of the method development for the use in ...The compensation method aiming to reduce the irradiation on the user＇s body and to form a weak field area （a dark spot） in an antenna near region is considered. The results of the method development for the use in a narrow frequencies range are given. They show that under realistic conditions the compensation method allows reducing the irradiation power by a factor of 3-4 and more. The pattern changes are predictable and small, if the points of antennas placement are selected correctly. The dark spot necessity near the transmitter is not limited by mobile communication. A man often uses a low-power radio station, which is placed nearby in a vehicle, and it is necessary to protect from irradiation not only user but also other passengers. In the paper, it is shown that broadband field compensation can be achieved in various structures where the needed anti-phase fields are created either by identical antennas or by radiators located at equal distance from the compensation point, or by flat reflectors.展开更多
In orthogonal frequency division multiplexing(OFDM) systems,for given total transmit power,insertion of the noninformation bearing cyclic prefix(CP) will reduce the effective energy per information bit.Generally,the e...In orthogonal frequency division multiplexing(OFDM) systems,for given total transmit power,insertion of the noninformation bearing cyclic prefix(CP) will reduce the effective energy per information bit.Generally,the energy loss is proportional to the ratio of CP length to the symbol duration.If the CP is too long,the energy loss will be considerable high.In this paper,we propose an energy efficient transmission scheme for OFDM systems in Long Term Evolution(LTE) which is developed based on reduction of the CP energy.Simulation results show that the proposed method can save up to about10%of the total energy,while keeping almost the same bit-error-rate(BER) performance in some applications.展开更多
Human body communication is proposed as a promising body proximal comanunication tech- nology for body sensor networks. To achieve low power and slmll volume ill the sensor nodes, a Ra-dio Frequency （RF） application...Human body communication is proposed as a promising body proximal comanunication tech- nology for body sensor networks. To achieve low power and slmll volume ill the sensor nodes, a Ra-dio Frequency （RF） application-specific integrated circuit transceiver tbr Human Body Commnunication （HBC） is presented and the characteristics of HBC are investigated. A high data rate On-Off Keying （OOK）/Frequency-Shift Keying （FSK） modulation protocol and an OOK/FSK delrodulator circuit are introduced in this paper, with a data-rate-to-carrier-frequency ratio up to 70%. A low noise amplifier is proposed to handle the dynamic range problem and improve the sensitivity of the receiver path. In addi-tion, a low power autonmatic-gain-control system is realized using a novel architecture, thereby render-ing the peak detector circuit and loop filter unneces-sary. Finally, the complete chip is fabricated. Simula-tion results suggest receiver sensitivity to be-75 dBm. The transceiver shows an overall power con-smxption of 32 mW when data rate is 5 Mbps, de-livering a P1dB output power of - 30 dBm.展开更多
文摘The compensation method aiming to reduce the irradiation on the user＇s body and to form a weak field area （a dark spot） in an antenna near region is considered. The results of the method development for the use in a narrow frequencies range are given. They show that under realistic conditions the compensation method allows reducing the irradiation power by a factor of 3-4 and more. The pattern changes are predictable and small, if the points of antennas placement are selected correctly. The dark spot necessity near the transmitter is not limited by mobile communication. A man often uses a low-power radio station, which is placed nearby in a vehicle, and it is necessary to protect from irradiation not only user but also other passengers. In the paper, it is shown that broadband field compensation can be achieved in various structures where the needed anti-phase fields are created either by identical antennas or by radiators located at equal distance from the compensation point, or by flat reflectors.
基金the Chinese 863 Program，National "Eleventh Five-year" Project of China，the National Natural Science Foundation of China
文摘In orthogonal frequency division multiplexing(OFDM) systems,for given total transmit power,insertion of the noninformation bearing cyclic prefix(CP) will reduce the effective energy per information bit.Generally,the energy loss is proportional to the ratio of CP length to the symbol duration.If the CP is too long,the energy loss will be considerable high.In this paper,we propose an energy efficient transmission scheme for OFDM systems in Long Term Evolution(LTE) which is developed based on reduction of the CP energy.Simulation results show that the proposed method can save up to about10%of the total energy,while keeping almost the same bit-error-rate(BER) performance in some applications.
基金This study was supported partially by the Projects of National Natural Science Foundation of China under Crants No. 60932001, No.61072031 the National 863 Program of China un-der Crant No. 2012AA02A604+3 种基金 the National 973 Program of China under Cwant No. 2010CB732606 the Next Generation Communication Technology Major Project of National S＆T un-der Crant No. 2013ZX03005013 the ＂One-hundred Talent＂ and the ＂Low-cost Healthcare＂ Programs of Chinese Academy of Sciences and the Guangdong Innovation Research Team Funds for Low-cost Healthcare and Irrage-Guided Therapy.
文摘Human body communication is proposed as a promising body proximal comanunication tech- nology for body sensor networks. To achieve low power and slmll volume ill the sensor nodes, a Ra-dio Frequency （RF） application-specific integrated circuit transceiver tbr Human Body Commnunication （HBC） is presented and the characteristics of HBC are investigated. A high data rate On-Off Keying （OOK）/Frequency-Shift Keying （FSK） modulation protocol and an OOK/FSK delrodulator circuit are introduced in this paper, with a data-rate-to-carrier-frequency ratio up to 70%. A low noise amplifier is proposed to handle the dynamic range problem and improve the sensitivity of the receiver path. In addi-tion, a low power autonmatic-gain-control system is realized using a novel architecture, thereby render-ing the peak detector circuit and loop filter unneces-sary. Finally, the complete chip is fabricated. Simula-tion results suggest receiver sensitivity to be-75 dBm. The transceiver shows an overall power con-smxption of 32 mW when data rate is 5 Mbps, de-livering a P1dB output power of - 30 dBm.
