• Journal of Communications and Networks
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• v.12 no.2
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• pp.103-113
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• 2010

In this paper, a tradeoff between the total energy consumption-per-bit and the end-to-end rate under spatial reuse in wireless multi-hop network is developed and analyzed. The end-to-end rate of the network is the number of information bits transmitted (end-to-end) per channel use by any node in the network that is forwarding the data. In order to increase the bandwidth efficiency, spatial reuse is considered whereby simultaneous relay transmissions are allowed provided there is a minimum separation between such transmitters. The total energy consumption-per-bit includes the energy transmitted and the energy consumed by the receiver to process (demodulate and decoder) the received signal. The total energy consumption-per-bit is normalized by the distance between a source-destination pair in order to be consistent with a direct (single-hop) communication network. Lower bounds on this energy-bandwidth tradeoff are analyzed using convex optimization methods. For a given location of relays, it is shown that the total energy consumption-per-bit is minimized by optimally selecting the end-to-end rate. It is also demonstrated that spatial reuse can improve the bandwidth efficiency for a given total energy consumption-per-bit. However, at the rate that minimizes the total energy consumption-per-bit, spatial reuse does not provide lower energy consumption-per-bit compared to the case without spatial reuse. This is because spatial reuse requires more receiver energy consumption at a given end-to-end rate. Such degraded energy efficiency can be compensated by varying the minimum separation of hops between simultaneous transmitters. In the case of equi-spaced relays, analytical results for the energy-bandwidth tradeoff are provided and it is shown that the minimum energy consumption-per-bit decreases linearly with the end-to-end distance.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.12
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• pp.1078-1085
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• 2011

In this paper, we analyze the relationship between energy per bit and the data rate with the variation of the system bandwidth. A existing power model is mathematical model to express power consumption of each device. In this paper, we have to investigate the system level energy model for the RF front-end of a wireless transceiver. Also, the effects of the signal bandwidth, PAR, date rate, modulation level, transmission distance, specific attenuation of frequency band, and the signal center frequency on the RF front-end energy consumption and system capacity are considered. Eventually, we analyze the relationship between energy per bit and the data rate with the variation of the system bandwidth so that we simulate the minimum energy per bit in the several Gbps data rate using Shannon capacity theory.

• Journal of the Korean Institute of Telematics and Electronics
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• v.20 no.3
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• pp.52-60
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• 1983

This paper presents a complete analysis for the derivation of the probability of error for a fast (or multiple-hops per bit) frequency hopping spread spectrum system employing binary FSK modulation and noncoherent reception in the presence of partial-band noise jamming and thermal noise. The worst-case error rate performances were obtained numerically and presented as a function of E /N with L as a parameter, where E /N and L are the signal bit energy-to-jamiming density ratio and the number of hops per bit, respectively.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.7
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• pp.1-8
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• 1997

In this paper, Stokes parameters which represent the states of polarization of transmitted light are determined by potential function, which is used to obtain signals points in a multidimensional Euclidean structure. And performance of multilevel polarization shift keying(POLSK) system using the obtained parameters is also represented and analyzed. As results, bit error rate of multilevel POLSK system using the potential function is shown to be lower than the conventional one using the distance matrix. And as number of levels increases, the number of photons per bit for bit error rate of 10$^{-9}$ is also increased linearly. The multilevel POLSK system, therefore, is an energy efficient modulation technque as compared with the convnetional ones.

• Proceedings of the IEEK Conference
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• 2002.07c
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• pp.1543-1546
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• 2002

The expandable 4 bit adder/subtracter IC was designed using the adiabatic and dynamic CMOS logic (ADCL) circuit as the ultra-low power consumption basic logic circuit and the IC was fabricated using a standard 1.2 ${\mu}$ CMOS process. As the result the steady operation of 4 bit addition and subtraction has been confirmed even if the frequency of the sinusoidal supply voltage is higher than 10MHz. Additionally, by the simulation, at the frequency of 10MHz, energy consumption per operation is obtained as 93.67pJ (ar addition and as 118.67pJ for subtraction, respectively. Each energy is about 1110 in comparison with the case in which the conventional CMOS logic circuit is used. A simple and low power oscillation circuit is also proposed as the power supply circuit f3r the ADCL circuit. The oscillator operates with a less one volt of DC supply voltage and around one milli-watts power dissipation.

• ETRI Journal
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• v.42 no.3
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• pp.341-350
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• 2020

In a wireless sensor network (WSN), the data transmission technique based on the cooperative multiple-input multiple-output (CMIMO) scheme reduces the energy consumption of sensor nodes quite effectively by utilizing the space-time block coding scheme. However, in networks with high node density, the scheme is ineffective due to the high degree of correlated data. Therefore, to enhance the energy efficiency in high node density WSNs, we implemented the distributed source coding (DSC) with the virtual multiple-input multiple-output (MIMO) data transmission technique in the WSNs. The DSC-MIMO first compresses redundant source data using the DSC and then sends it to a virtual MIMO link. The results reveal that, in the DSC-MIMO scheme, energy consumption is lower than that in the CMIMO technique; it is also lower in the DSC single-input single-output (SISO) scheme, compared to that in the SISO technique at various code rates, compression rates, and training overhead factors. The results also indicate that the energy consumption per bit is directly proportional to the velocity and training overhead factor in all the energy saving schemes.

• ETRI Journal
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• v.36 no.3
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• pp.506-509
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• 2014

This paper studies the energy efficiency power allocation for cognitive radio networks based on uplink orthogonal frequency-division multiplexing. The power allocation problem is intended to minimize the maximum energy efficiency measured by "Joule per bit" metric, under total power constraint and robust aggregate mutual interference power constraint. However, the above problem is non-convex. To make it solvable, an equivalent convex optimization problem is derived that can be solved by general fractional programming. Then, a robust energy efficiency power allocation scheme is presented. Simulation results corroborate the effectiveness of the proposed methods.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.165-167
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• 2006

In this paper we present a new-generation sensor network processor which is not optimized in circuit level, but in system architecture level. The new design build on a conventional processor architecture, improving the design by focusing on application oriented specification, ISA, and micro-architectural optimization that reduce overall design size and advance energy-per-instruction. The design employs harvard architecture, 8-bit data paths, and an compact 19 bit wide RISC ISA. The design also features a unique interrupt handler which offloads periodical monitoring jobs from the main part of CPU. Our most efficient design is capable of running at 300 KHz (0.3 MIPS) while consuming only about few pJ/instruction.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.2
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• pp.15-21
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• 2007

In this paper, we propose a technique of a practical symbol acquisition and tracking using a low complex ADC and simple digital circuits for noncoherent asynchronous impulse-radio-based Ultra Wideband (IR-UWB) receiver based on energy detection. Compared to previous approaches of detecting an exact acquisition time that require much hardware resource, the proposed technique is to detect the target symbol by finding the symbol acquisition interval per symbol with a target symbo, thus the complexity of the complete signal processing and power consumption by ADC are reduced. To do this, we define the bit decision window (BDW) and analyze the relation between SNR, hardware resource, size of BDW and BER(Bit Error Rate). Using the results, the optimum BDW size for the minimum BER with limited hardware resource is selected. The proposed synchronization technique is verified with an aid of a simulator programmed by considering practical impulse channels.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.6
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• pp.1115-1125
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• 1994

In this paper, an efficient concatenated coding scheme under the satellite channel is presented. The performance of this scheme in terms of bit error rate versus energy per information bit over white gaussian noise power density E/N has been evaluated via computer simulation as a function of various system parameters. To achieve accuracy in simulation results, the distortions caused from the satellite channel, such as the nonlinearity of the TWTA(traveling wave tube amplifier), signal distortions of the input and output filters, has been considered. The simulation results show that, through using the 2/3 punctured convolutional code as the inner code of the concatenated code system, the coding rate can be improved more over 16%, while maintaining the same system complexity and bit error performance.