• Title/Summary/Keyword: Bandwidth Efficiency

Search Result 794, Processing Time 0.638 seconds

Performance Evaluation of the Probability based MAC Protocol for Fair Transmission in WDM Metro Ring (WDM 메트로 링에서 공정한 전송을 위한 확률기반 MAC 프로토콜에 대한 성능 평가)

  • So Won-Ho;Kim Young-Chon
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.31 no.4B
    • /
    • pp.323-332
    • /
    • 2006
  • In this paper, we consider a WDM based metro ring connecting broadband access networks by using FT-TR (Fixed Transmitter-Tunable Receiver) type access nodes and a new MAC protocol for fair transmission is proposed. The basic channel access scheme is CSMA/CA(Carrier Sense Multiple Access with Collision Avoidance) and the transferred optical slot is changed to be empty slot by SS(Source-Stripping) which drops a packet from ring-rotated slot. This empty slot can be either used to send head-of-line packet in buffer or transmitted to next access node. In former cases, there is the improvement of network throughput, but latter case leads unfairness problem of transmission. Thus the proposed MAC protocol exploits the advantages form tow cases. It gives downstream access nodes chance to use empty slots and limits the unconditional usage of empty slots at upstream access nodes with probability as called p-Persistent MAC protocol. We use a numerical analysis to evaluate bandwidth efficiency and maximum node throughput and compares simulation results in terms of node throughput, fairness factor, transfer delay depending on probability. Under two different FT-TR type architectures for metro ring network the proposed MAC protocol is evaluated and compared.

A Resource Scheduling Based on Iterative Sorting for Long-Distance Airborne Tactical Communication in Hub Network (허브 네트워크에서의 장거리 공중 전술 통신을 위한 반복 정렬 기반의 자원 스케줄링 기법)

  • Lee, Kyunghoon;Lee, Dong Hun;Lee, Dae-Hong;Jung, Sung-Jin;Choi, Hyung-Jin
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.39C no.12
    • /
    • pp.1250-1260
    • /
    • 2014
  • In this paper, a novel resource scheduling, which is used for hub network based long distance airborne tactical communication, is proposed. Recently, some countries of the world has concentrated on developing data rate and networking performance of CDL, striving to keep pace with modern warfare, which is changed into NCW. And our government has also developed the next generation high capacity CDL. In hub network, a typical communication structure of CDL, hybrid FDMA/TDMA can be considered to exchange high rate data among multiple UAVs simultaneously, within limited bandwidth. However, due to different RTT and traffic size of UAV, idle time resource and unnecessary packet transmission delay can occur. And these losses can reduce entire efficiency of hub network in long distance communication. Therefore, in this paper, we propose RTT and data traffic size based UAV scheduling, which selects time/frequency resource of UAVs by using iterative sorting algorithm. The simulation results verified that the proposed scheme improves data rate and packet delay performance in low complexity.

Fast Motion Estimation for Variable Motion Block Size in H.264 Standard (H.264 표준의 가변 움직임 블록을 위한 고속 움직임 탐색 기법)

  • 최웅일;전병우
    • Journal of the Institute of Electronics Engineers of Korea SP
    • /
    • v.41 no.6
    • /
    • pp.209-220
    • /
    • 2004
  • The main feature of H.264 standard against conventional video standards is the high coding efficiency and the network friendliness. In spite of these outstanding features, it is not easy to implement H.264 codec as a real-time system due to its high requirement of memory bandwidth and intensive computation. Although the variable block size motion compensation using multiple reference frames is one of the key coding tools to bring about its main performance gain, it demands substantial computational complexity due to SAD (Sum of Absolute Difference) calculation among all possible combinations of coding modes to find the best motion vector. For speedup of motion estimation process, therefore, this paper proposes fast algorithms for both integer-pel and fractional-pel motion search. Since many conventional fast integer-pel motion estimation algorithms are not suitable for H.264 having variable motion block sizes, we propose the motion field adaptive search using the hierarchical block structure based on the diamond search applicable to variable motion block sizes. Besides, we also propose fast fractional-pel motion search using small diamond search centered by predictive motion vector based on statistical characteristic of motion vector.

Design of Binary Constant Envelope System using the Pre-Coding Scheme in the Multi-User CDMA Communication System (다중 사용자 CDMA 통신 시스템에서 프리코딩 기법을 사용한 2진 정진폭 시스템 설계)

  • 김상우;유흥균;정순기;이상태
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.15 no.5
    • /
    • pp.486-492
    • /
    • 2004
  • In this paper, we newly propose the binary CA-CDMA(constant amplitude CDMA) system using pre-coding method to solve the high PAPR problem caused by multi-user signal transmission in the CDMA system. 4-user CA-CDMA, the basis of proposed binary CA-CDMA system, makes binary output signal for 4 input users. It produces the output of binary(${\pm}$2) amplitude by using a parity signal resulting from the XOR operation of 4 users data. Another sub-channel or more bandwidth is not necessary because it is transmitted together with user data and can be easily recovered in the receiver. The extension of the number of users can be possible by the simple repetition of the basic binary 4-user CA-CDMA. For example, binary 16-user CA-CDMA is made easily by allocating the four 4-user CA-CDMA systems in parallel and leading the four outputs to the fifth 4-user CA-CDMA system as input, because the output signal of each 4-user CA-CDMA is also binary. By the same extension procedure, binary 64 and 256-user CA-CDMA systems can be made with the constant amplitude. As a result, the code rate of this proposed CA-CDMA system is just 1 and binary CA-CDMA does not change the transmission rate with the constant output signal(PAPR = 0 ㏈). Therefore, the power efficiency of the HPA can be maximized without the nonlinear distortion. From the simulation results, it is verified that the conventional CDMA system has multi-level output signal, but the proposed binary CA-CDMA system always produces binary output. And it is also found that the BER of conventional CDMA system is increased by nonlinear HPA, but the BER of proposed binary CA-CDMA system is not changed.

Multi-Band Internal Chip Antenna Using Multi-Layer Substrate for Mobile Handset (Multi-Layer 구조를 사용한 다중 대역 내장형 칩 안테나)

  • Cho, Sang-Hyeok;Cho, Il-Hoon;Lee, In-Young;Pyo, Seong-Min;Baik, Jung-Woo;Kim, Young-Sik
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.19 no.7
    • /
    • pp.778-784
    • /
    • 2008
  • In this paper, a chip antenna using multi-layer configuration for multi-band operation, such as GSM, DCS, pcs, WCDMA, and Mobile WiMAX for 2.3 GHz is proposed. This proposed antenna is a PIFA structure with multi-layer configuration fabricated on R04003 substrate(${\varepsilon}_r=3.4$) and its size is $22{\times}5.5{\times}4.0\;mm^3$. Multi-layer structure can effectively reduce the size of an antenna from a reuse of air-space and can achieve broad bandwidth due to decrement of parallel capacitances from the insertion air-gap to the middle layer. The proposed antenna has a broadband operation by the high order resonance modes and the resonance at the top layer. The measured bandwidths with over 45 % radiation efficiency are 80 MHz($880{\sim}960\;MHz$) at the lower band and 690 MHz($1,710{\sim}2,400\;MHz$) at the higher band.

Transmission Method and Simulator Development with Channel bonding for a Mass Broadcasting Service in HFC Networks (HFC 망에서 대용량 방송서비스를 위한 채널 결합 기반 전송 방식 및 시뮬레이터 개발)

  • Shin, Hyun-Chul;Lee, Dong-Yul;You, Woong-Shik;Choi, Dong-Joon;Lee, Chae-Woo
    • Journal of Broadcast Engineering
    • /
    • v.16 no.5
    • /
    • pp.834-845
    • /
    • 2011
  • Massive broadcasting contents such as UHD(Ultra High Definition) TV which requires multi-channel capacity for transmission has been introduced in recent years. A transmission scheme with channel bonding has been considered for transmission of massive broadcasting contents. In HFC(Hybrid Fiber Coaxial) networks, DOCSIS 3.0(Data Over Cable Service Interface Specification 3.0) has already applied channel bonding schemes for up/downstream of data service. A method unlike DOCSIS 3.0 is required to introduce a channel bonding scheme in the broadcasting service having unidirectional transmission with a downstream. Since a massive broadcasting content requires several channels for transmission, VBR(Variable Bit Rate) transmission has been emerging for the bandwidth efficiency. In addition, research on channel allocation and resource scheduling is required to guarantee QoS(Quality of Service) for the broadcasting service based on VBR. In this paper, we propose a transmission method for mass broadcasting service in HFC network and show the UHD transmission simulator developed to evaluate the performance. In order to evaluate the performance, we define various scenarios. Using the simulator, we assess the possibility of channel bonding and VBR transmission for UHD broadcasting system to provide mass broadcasting service efficiently. The developed simulator is expected to contribute to the efficient transmission system development of mass broadcasting service.

Design and Implementation of ISO/IEEE 11073 DIM Transmission Structure Based on oneM2M for IoT Healthcare Service (사물인터넷 헬스케어 서비스를 위한 oneM2M기반 ISO/IEEE 11073 DIM 전송 구조 설계 및 구현)

  • Kim, Hyun Su;Chun, Seung Man;Chung, Yun Seok;Park, Jong Tae
    • Journal of the Institute of Electronics and Information Engineers
    • /
    • v.53 no.4
    • /
    • pp.3-11
    • /
    • 2016
  • In the environment of Internet of Things (IoT), IoT devices are limited by physical components such as power supply and memory, and also limited to their network performance in bandwidth, wireless channel, throughput, payload, etc. Despite these limitations, resources of IoT devices are shared with other IoT devices. Especially, remote management of the information of devices and patients are very important for the IoT healthcare service, moreover, providing the interoperability between the healthcare device and healthcare platform is essential. To meet these requirements, format of the message and the expressions for the data information and data transmission need to comply with suitable international standards for the IoT environment. However, the ISO/IEEE 11073 PHD (Personal Healthcare Device) standards, the existing international standards for the transmission of health informatics, does not consider the IoT environment, and therefore it is difficult to be applied for the IoT healthcare service. For this matter, we have designed and implemented the IoT healthcare system by applying the oneM2M, standards for the Internet of Things, and ISO/IEEE 11073 DIM (Domain Information Model), standards for the transmission of health informatics. For the implementation, the OM2M platform, which is based on the oneM2M standards, has been used. To evaluate the efficiency of transfer syntaxes between the healthcare device and OM2M platform, we have implemented comparative performance evaluation between HTTP and CoAP, and also between XML and JSON by comparing the packet size and number of packets in one transaction.

Performance Evaluation of the MAC Protocols for WDM Metro Ring with Wavelength-Shared Nodes Connecting Broadband Access Networks (대역 액세스 망을 연결하는 파장 공유 노드 기반 WDM 메트로 링의 MAC 프로토콜 성능 평가)

  • So Won-Ho
    • Journal of the Institute of Electronics Engineers of Korea TC
    • /
    • v.43 no.1 s.343
    • /
    • pp.111-120
    • /
    • 2006
  • In this paper, a node architecture of WDM metro network for connecting broadband access networks to converge wire/wireless networks. In consideration of the proposed node architecture and network requirements we proposed and evaluated medium access control protocols. We review WDM related technologies of sub-carrier multiplexing and optical components in order to resolve the bottleneck between optical backbone networks md access networks, and a access node architecture sharing common wavelength is introduced. Source-stripping (SS) MAC protocol Is evaluated under the proposed functional node architecture. DS+IS (Destination-Stripping and Source-Stripping) and DS+IS (Destination-Stripping and Intermediate-Stripping) MAC protocols are described to increase the slot-reuse factor which is low on SS MAC protocol. The key function of new MAC protocols regards the optical switch module of proposed node architecture and helps intermediate or source access nodes for dropping slots to destinations of different wavelength group. Thus, slot-reuse factor increases as the MAC protocols reduce the unnecessary ring-rotation of transferred slots. We use a numerical analysis to expect bandwidth efficiency and maximum throughput by slot-reuse factor Throughput network simulation, the verification of throughput, queuing delay, and transmission fairness are compared among MAC protocols.

Fabrication of IMT-2000 Linear Power Amplifier using Current Control Adaptation Method in Signal Cancelling Loop (신호 제거 궤환부의 전류 제어 적응형 알고리즘을 이용한 IMT-2000용 선형화 증폭기 제작)

  • 오인열;이창희;정기혁;조진용;라극한
    • Journal of the Institute of Electronics Engineers of Korea TC
    • /
    • v.40 no.1
    • /
    • pp.24-36
    • /
    • 2003
  • The digital mobile communication will be developed till getting multimedia service in anyone, any where, any time. Theses requiring items are going to be come true via IMT-2000 system. Transmitting signal bandwidth of IMT-2000 system is 3 times as large as IS-95 system. That is mean peak to average of signal is higher than IS-95A system. So we have to design it carefully not to effect in adjacent channel. HPA(High Power Amplifier) located in the end point of system is operated in 1-㏈ compression point(Pl㏈), then it generates 3rd and 5th inter modulation signals. Theses signals affect at adjacent channel and RF signal is distorted by compressed signal which is operated near by Pl㏈ point. Then the most important design factor is how we make HPA having high linearity. Feedback, Pre-distorter and Feed-forward methods are presented to solve theses problems. Feed-forward of these methods is having excellent improving capacity, but composed with complex structure. Generally, Linearity and Efficiency in power amplifier operate in the contrary, then it is difficult for us to find optimal operating point. In this paper we applied algorithm which searches optimal point of linear characteristics, which is key in Power Amplifier, using minimum current point of error amplifier in 1st loop. And we made 2nd loop compose with new structure. We confirmed fabricated LPA is operated by having high linearity and minimum current condition with ACPR of -26 ㏈m max. @ 30㎑ BW in 3.515㎒ and ACLR of 48 ㏈c max@${\pm}$㎒ from 1W to 40W.

Soft Decision based Advanced Receiver to Suppress and Cancel the Interference in D2D Communication Underlaying Cellular Network (셀룰러 네트워크상의 D2D 통신 시스템에서 간섭 억제 및 제거를 위한 연판정 기반 향상된 수신기)

  • Moon, Sangmi;Chu, Myeonghun;Kim, Hanjong;Kim, Daejin;Kim, Cheolsung;Hwang, Intae
    • Journal of the Institute of Electronics and Information Engineers
    • /
    • v.52 no.12
    • /
    • pp.10-21
    • /
    • 2015
  • Cellular Network assisted device-to-device (D2D) communication has been growing to reduce the overload of eNodeB and mitigate the frequency shortage. However, by sharing the uplink frequency resource with the cellular network, the interference between cellular and D2D is increased. In this paper, we propose the advanced receiver based on soft decision to reduce the interference between cellular and D2D. The proposed receiver can suppress and cancel the interference by calculating the unbiased estimation value of interference signal using minimum mean square error (MMSE) or interference rejection combing (IRC) receiver. The interference signal is updated using soft information expressed by log-likelihood ratio (LLR). We perform a system level simulation based on the 20-MHz bandwidth of the 3GPP LTE-A system. Simulation results show that the proposed receiver can improve SINR, throughput and spectral efficiency compared to conventional receivers.