• Title/Summary/Keyword: random access MAC

Search Result 55, Processing Time 0.027 seconds

Adaptive and Prioritized Random Access and Resource Allocation Schemes for Dynamic TDMA/TDD Protocols

  • Choi, Hyun-Ho
    • Journal of information and communication convergence engineering
    • /
    • v.15 no.1
    • /
    • pp.28-36
    • /
    • 2017
  • The medium access control (MAC) protocol based on dynamic time division multiple access/time division duplex (TDMA/TDD) is responsible for random access control and radio resource allocation in dynamic traffic environments. These functions of random access and resource allocation are very important to prevent wastage of resources and improve MAC performance according to various network conditions. In this paper, we propose new random access and resource allocation schemes to guarantee quality of service (QoS) and provide priority services in a dynamic TDMA/TDD system. First, for the QoS guarantee, we propose an adaptive random access and resource allocation scheme by introducing an access probability. Second, for providing priority service, we propose a priority-based random access and resource allocation scheme by extending the first adaptive scheme in both a centralized and a distributed manner. The analysis and simulation results show that the proposed MAC protocol outperforms the legacy MAC protocol using a simple binary exponential backoff algorithm, and provides good differential performance according to priorities with respect to the throughput and delay.

Random Access Channel with Retransmission Gain

  • Shi, Junmin;Sun, Yi;Zhang, Xiaochen;Xiao, Jizhong
    • IEIE Transactions on Smart Processing and Computing
    • /
    • v.2 no.3
    • /
    • pp.148-159
    • /
    • 2013
  • An analysis of the throughput and stability region of random access systems is currently of interest in research and industry. This study evaluated the performance of a multiuser random access channel with a retransmission gain. The channel was composed of a media access control (MAC) determined by the transmission probabilities and a multiuser communication channel characterized by the packet reception probabilities as functions of the number of packet transmissions and the collision status. The analysis began with an illustrative two-user channel, and was extended to a general multiuser channel. For the two-user channel, a sufficient condition was derived, under which the maximum throughput was achieved with a control-free MAC. For the channel with retransmission gain, the maximum steady throughput was obtained in a closed form. The condition under which the random access channel can acquire retransmission gain was also obtained. The stability region of the general random access channel was derived. These results include those of the well-known orthogonal channel, collision channel and slotted Aloha channel with packet reception as a special instance. The analytical and numerical results showed that exploiting the retransmission gain can increase the throughput significantly and expand the stability region of the random access channel. The analytical results predicted the performance in the simulations quite well.

  • PDF

Terminal-Assisted Hybrid MAC Protocol for Differentiated QoS Guarantee in TDMA-Based Broadband Access Networks

  • Hong, Seung-Eun;Kang, Chung-Gu;Kwon, O-Hyung
    • ETRI Journal
    • /
    • v.28 no.3
    • /
    • pp.311-319
    • /
    • 2006
  • This paper presents a terminal-assisted frame-based packet reservation multiple access (TAF-PRMA) protocol, which optimizes random access control between heterogeneous traffic aiming at more efficient voice/data integrated services in dynamic reservation TDMA-based broadband access networks. In order to achieve a differentiated quality-of-service (QoS) guarantee for individual service plus maximal system resource utilization, TAF-PRMA independently controls the random access parameters such as the lengths of the access regions dedicated to respective service traffic and the corresponding permission probabilities, on a frame-by-frame basis. In addition, we have adopted a terminal-assisted random access mechanism where the voice terminal readjusts a global permission probability from the central controller in order to handle the 'fair access' issue resulting from distributed queuing problems inherent in the access network. Our extensive simulation results indicate that TAF-PRMA achieves significant improvements in terms of voice capacity, delay, and fairness over most of the existing medium access control (MAC) schemes for integrated services.

  • PDF

Random Channel Allocation Scheme Based on Split Algorithm in HIPERLAN 2 (HIPERLAN Type 2에서 Split 알고리즘에 기반한 랜덤채널 할당 기법)

  • 황의석;고유창;이승규;윤철식;이형우;조충호
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.28 no.9A
    • /
    • pp.717-727
    • /
    • 2003
  • The HIPERLAN/2(HIgh PERformance Local Area Network Type2) is one of the wireless LAN standards for providing raw data rates of up to 54 Mbps. The MAC protocol of HIPERLAN/2 is based on TDMA/TDD, and resources in one MAC frame can be allocated dynamically by Access Point(AP). The random channel(RCH) is defined for the purpose of giving a mobile terminal the opportunity to request transmission resources in the uplink MAC frames. It is desirable that the number of RCHs is dynamically adapted by the AP depending on the current traffic situation. Allocation of excessive RCHs may waste radio resources and insufficient RCHs compared to traffic loads may result in many collisions in access attempts. We propose an RCH allocation scheme based on split algorithm in HIPERLAN/2. The simulation and analytic results show that the proposed scheme achieves a higher channel throughput, lower access delay and delay jitter than previously proposed RCH allocation schemes.

Performance Analysis of MAC Protocol for Packet Data Service in CDMA Based Mobile Communication Systems (CDMA 기반 이동통신 시스템에서의 패킷 데이터 서비스를 위한 MAC 프로토콜의 성능분석)

  • 박성수;조동호;송영재
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.24 no.7A
    • /
    • pp.973-986
    • /
    • 1999
  • In this paper, we propose MAC protocol that consists of channel access mechanism and transmission mechanism to support effective wireless packet data service. In channel access mechanism, broadcast channel announces status information of random access channel, and mobile station tries random access based on status information. Also, mobile station has access probability to prevent collision increase due to transmission of short message. For effective transmission, mobile station changes transmission rate based on transmission queue status to adapt burst traffic characteristics. In restricted environments of transmission code and bandwidth, proposed protocol shows better performance than cdma2000 system.

  • PDF

An Improved Link Access Scheme Using Carrier Sensing Mechanism In DSRC. (단거리전용통신에서 반송파 감지기법을 이용한 개선된 링크접근 방식)

  • 박정수;조동호;오종택;이병태
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.24 no.10A
    • /
    • pp.1453-1461
    • /
    • 1999
  • In this paper, we propose a new scheme that improve the performance of the conventional link access scheme in DSRC MAC and evaluate the performance of the proposed scheme. By using carrier sensing mechanism in random access channels, the proposed scheme can reduce the probability that the collisions among the link access traffics with different priorities may occur in random access channels, and provide differentiated link access delays according to the priorities. Furthermore, the proposed scheme can improve the performance of link access by using modified reservation mode. According to simulation results, it is shown that the proposed scheme is better than conventional method in view of the mean access delay and throughput in random access channels.

  • PDF

Variable RCH Channel Assignment Scheme in HiperLAN/2 System (HiperLAN/2 시스템에서 가변적인 RCH 채널 할당방안)

  • Jang, soon-gun;Jang, jae-hwan;Lim, seog-ku
    • Proceedings of the Korea Contents Association Conference
    • /
    • 2009.05a
    • /
    • pp.83-87
    • /
    • 2009
  • The MAC protocol of HiperLAN/2 is based on TDMA/TDD. Mobile terminal acquires a data transmission opportunity as successfulness in channel competition through RCH (Random CHannel) phase. Therefore, AP (Access Point) be able to dynamically assign optimum RCH at next frame according to the number of success and collision. In this paper, we suggest scheme that fluctuate RCH (Random CHannel) number as fixed value considering success and collision for improvement of performance in HiperLAN/2. To prove efficiency of proposed scheme, a lots of simulations are conducted and analyzed in view of throughput and access delay.

  • PDF

Dynamic Channel Assignment Scheme Based on the Number of Success and Collision of Random Channel in HIPERLAN/2 (HIPERLAN/2에서 랜덤채널의 성공수와 충돌수에 기반한 동적 채널할당 방안)

  • Lim, Seog-Ku
    • Journal of Digital Contents Society
    • /
    • v.12 no.3
    • /
    • pp.347-353
    • /
    • 2011
  • In HIPERLAN/2, the radio channels are assigned by AP(Access Point) that is centrally operated and the MAC protocol is based on TDMA/TDD. Mobile terminal that data transmission is necessary to uplink requests radio resource to AP through RCH channel. The changing number of RCHs in each MAC frame is important because too many RCHs may result in a waste of radio resources and too few RCHs may result in many access collisions and prolong time that connect to AP. Hence the number of RCH should be allocated properly according to traffic. From these point, this paper proposes an scheme that dynamically assigned the number of RCH which is based on the number of success and collision of message in previous MAC frame. To prove efficiency of proposed scheme, lots of simulations are conducted and analyzed.

Performance Evaluation of the HomePNA 3.0 Asynchronous MAC Mode with Collision Management Protocol (HomePNA 3.0 비동기 MAC 모드의 Collision Management Protocol 성능 분석)

  • 김희천;정민영;이태진
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.29 no.7A
    • /
    • pp.727-734
    • /
    • 2004
  • Collision Management Protocol (CMP) efficiently resolves collisions when data frames are transmitted in networks consisting of HomPNA 3.0 asynchronous MAC mode device with random access. Unlike Distributed Fair Priority Queueing (DFPQ) algorithm in HomePNA 2.0 or Binary Exponential Backoff (BEB) algorithm in IEEE 802.11, order of retransmission is decided according to Collision Signaling Sequence (CSS) values allocated to each device. Thus, CMP can minimize the number of mean collisions because order of retransmission is decided in a deterministic way. In this paper. we evaluate the saturation performance of CMP in HomePNA 3.0 using an analytic method.

Design and Implementation of MAC Protocol for Wireless LAN (무선 LAN MAC 계층 설계 및 구현)

  • 김용권;기장근;조현묵
    • Proceedings of the IEEK Conference
    • /
    • 2001.06a
    • /
    • pp.253-256
    • /
    • 2001
  • This paper describes a high speed MAC(Media Access Control) function chip for IEEE 802.11 MAC layer protocol. The MAC chip has control registers and interrupt scheme for interface with CPU and deals with transmission/reception of data as a unit of frame. The developed MAC chip is composed of protocol control block, transmission block, and reception block which supports the BCF function in IEEE 802.11 specification. The test suite which is adopted in order to verify operation of the MAC chip includes various functions, such as RTS-CTS frame exchange procedure, correct IFS(Inter Frame Space)timing, access procedure, random backoff procedure, retransmission procedure, fragmented frame transmission/reception procedure, duplicate reception frame detection, NAV(Network Allocation Vector), reception error processing, broadcast frame transmission/reception procedure, beacon frame transmission/reception procedure, and transmission/reception FIEO operation. By using this technique, it is possible to reduce the load of CPU and firmware size in high speed wireless LAN system.

  • PDF