• Title/Summary/Keyword: Time division multiple access

Search Result 364, Processing Time 0.021 seconds

Maximum Ratio Transmission for Space-Polarization Division Multiple Access in Dual-Polarized MIMO System

  • Hong, Jun-Ki;Jo, Han-Shin;Mun, Cheol;Yook, Jong-Gwan
    • KSII Transactions on Internet and Information Systems (TIIS)
    • /
    • v.9 no.8
    • /
    • pp.3054-3067
    • /
    • 2015
  • The phenomena of higher channel cross polarization discrimination (XPD) is mainly observed for future wireless technologies such as small cell network and massive multiple-input multiple-output (MIMO) system. Therefore, utilization of high XPD is very important and space-polarization division multiple access (SPDMA) with dual-polarized MIMO system could be a suitable solution to high-speed transmission in high XPD environment as well as reduction of array size at base station (BS). By SPDMA with dual-polarized MIMO system, two parallel data signals can be transmitted by both vertically and horizontally polarized antennas to serve different mobile stations (MSs) simultaneously compare to conventional space division multiple access (SDMA) with single-polarized MIMO system. This paper analyzes the performance of SPDMA for maximum ratio transmission (MRT) in time division duplexing (TDD) system by proposed dual-polarized MIMO spatial channel model (SCM) compare to conventional SDMA. Simulation results indicate that how SPDMA utilizes the high XPD as the number of MS increases and SPDMA performs very close to conventional SDMA for same number of antenna elements but half size of the array at BS.

Study on Performance Enhancement for a Cyclic Code Shift Keying Frequency Hopping Spread Spectrum/Time Division Multiple Access System (순환천이변조 주파수도약대역확산/시분할다중접속 시스템의 성능 개선에 관한 연구)

  • Kim, Eun-Cheol;Kim, Seung-Chun;Lee, Hyung-Keun
    • Journal of IKEEE
    • /
    • v.16 no.1
    • /
    • pp.51-55
    • /
    • 2012
  • In this paper, we propose to employ a ternary sequence as a cyclic code shift keying (CCSK) modulation sequence. And we simulate the performance in a frequency hopping spread spectrum/time division multiple access (FHSS/TDMA) system with CCSK. Wireless channel is modeled as Rayleigh fading channel. From the simulation results, it is demonstrated that the system adopting the ternary sequence as a CCSK sequence has higher performance than that with a random sequence.

The Design and Performance analysis of a Process Migration Facility in a Distributed System (분산 시스템에서 프로세스 이주 기능의 설계와 성능 평가)

  • 엄태범;송주석
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.17 no.7
    • /
    • pp.656-665
    • /
    • 1992
  • In this paper, the performance of the various multiple access techniques for the mobile computer network has been studiedi in the consideration of the charactersitics of the mobile cimmunication channel. In the case of the hidden node occurring. It could be seen that the performance of the code division multiple access (CDMA) technique with simultaneous access function is better than that of the other packet access methods such as carrier sendsed multiple access (CDMA), busy tone multiple access (BTMA) and idle signal multiple access (ISMA) in the view of the throughput and mean delay time. Also, it has been shown that the performance of the CDMA method is superior to that of other packet access techniques such as multiple access (CSMA), etc. when the fading effect or impulsive noise exists in the mobile channel, Especially, in the case of the distributed mobile network it has been shown that the receivertransmitter based CDMA method using the characteristics of CDMA effectively has better throughput and less mean delay time than the commontransmitter based CDMA technique.

  • PDF

Design of MJPEG Encoder for FH/TDD Multiple Transmissions (FH/TDD 다중전송용 MJPEG 부호화기 설계)

  • Kang, Min-Goo;Sonh, Seung-Il
    • Journal of Internet Computing and Services
    • /
    • v.12 no.4
    • /
    • pp.45-50
    • /
    • 2011
  • In this paper, the encoding time delay of FH/TDD(Frequency Hopping/Time Division Duplex) based Motion JPEG image compression CODEC is analyzed for radio video transmissions of multi-camera systems in a vehicle. And, Synchronized connection of minimum channel collision is designed with synchronized shift and access according to channel status for Motion JPEG based FH/TDD multiple access.

An SS_RRA Protocol for Integrated Voice/Data Services in Packet Radio Networks

  • Lim, In-Taek
    • Journal of information and communication convergence engineering
    • /
    • v.5 no.2
    • /
    • pp.88-92
    • /
    • 2007
  • In this paper, an SS-RRA protocol that is based on Code Division Multiple Access is proposed and analyzed under the integrated voice and data traffic load. The backward logical channels consist of slotted time division frames with multiple spreading codes per slot. The protocol uses a reservation mechanism for the voice traffic, and a random access scheme for the data traffic. A discrete-time, discrete-state Markov chain is used to evaluate the performance. The numerical results show that the performance can be significantly improved by a few distinct spreading codes.

A Study on the Performance of the Various Multiple Access for the Mobile Computer Network (이동 컴퓨터 통신망용 다중 엑세스 방식의 성능 연구)

  • 백지현;조동호;이영웅
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.17 no.7
    • /
    • pp.641-655
    • /
    • 1992
  • In this paper, the performance of the various multiple accesstechniques for the mobile computer network has been studied in the consideration of the characteristics. Of the mobile communication channel. In the case of the hidden node occurring, it could be seen that the performance of the code division multiple access(CDMA) technique. With simultaneous access function is better than that of the other packet access methods such as carrier sensed multiple access(CAMA). Busy tone mulitiple access(BTMA)and idle signal muitiple access(ISMA) in the view of the throuhtput and mean delay time. Also it has been shown that the performance of the CDMA method is superior to that of other packet access techniques such as multiple access(CSMA).etc when the fading effect or impulsive noise exists in the mobile channel. Especially in the case of the distributed mobile network. It has been shown that the receiver-transmitter based CDMA method using the characteristics of CDMA effectively has better throughput and less mean delay time than the commontransmitter based CDMA technique.

  • PDF

Unified Optimal Power Allocation Strategy for MIMO Candidates in 3GPP HSDPA

  • Kim, Sung-Jin James;Kim, Ho-Jin;Lee, Kwang-Bok
    • ETRI Journal
    • /
    • v.27 no.6
    • /
    • pp.768-776
    • /
    • 2005
  • We compare the achievable throughput of time division multiple access (TDMA) multiple-input multiple-output (MIMO) schemes illustrated in the 3rd Generation Partnership Project (3GPP) MIMO technical report, versus the sum-rate capacity of space-time multiple access (STMA). These schemes have been proposed to improve the 3GPP high speed downlink packet access (HSDPA) channel by employing multiple antennas at both the base station and mobile stations. Our comparisons are performed in multi-user environments and are conducted using TDMA such as Qualcomm's High Data Rate and HSDPA, which is a simpler technique than STMA. Furthermore, we present the unified optimal power allocation strategy for HSDPA MIMO schemes by exploiting the similarity of multiple antenna systems and multi-user channel problems.

  • PDF

FlexRay: Protocol, Time Hierarchy, Message Frame, Communication Controller, and Conformance Test (FlexRay: 프로토콜, 시간 계층, 메시지 프레임, 커뮤니케이션 컨트롤러, 적합성 시험)

  • Seokjun Hahn;Sua Shin;Naeun Park;Chan Park;Daegi Lee;Seongsoo Lee
    • Journal of IKEEE
    • /
    • v.27 no.4
    • /
    • pp.668-678
    • /
    • 2023
  • FlexRay is an in-vehicle network with maximum two channels and maximum transmission speed of 10Mbps per channel. FlexRay exploits TDMA (Time Division Multiple Access) and FTDMA (Flexible Time division Multiple Access) to ensure real-time communication with efficient transmission, so it is used for real-time electronic control of safety-critical vehicular modules such as powertrain. This paper explains FlexRay protocol, time hierarchy, message frame, communication controller, and conformance test in detail based on ISO 17458 standard and FlexRay consortium documents.

The Design of STDMA(Self-Organized Time Division Multiple Access) Protocol Simulation Program (항공 감시용 다중접속방식 프로토콜 시뮬레이션 프로그램 설계)

  • Kim, In-Kyu;Ohn, Kyoung-Ryoon;Song, Jae-Hoon
    • Journal of Advanced Navigation Technology
    • /
    • v.12 no.6
    • /
    • pp.554-558
    • /
    • 2008
  • In this paper, we show that the SIDMA(Self-organized Time Division Multiple Access) protocol using aviation surveillance data link now, designs to the ICAO DO 9816 documentation sequence. This protocol makes use of the VDL(VHF Data Link) Mode 4 and UAT(Universal Access Transceiver) system's MAC(Media Access Control) layer. We make sure of the simulation result and implementation of STDMA protocol program in accompany with the ICAO documentation sequence. This program operates the slot allocation and reservation with report rate when protocol transmits data and calculates slot address.

  • PDF