Cluster-based self-organized synchronization scheme for femtocell network /
Femtocell is a recently developed technology in cellular wireless network which extends to indoor coverage for serving a small number of users. Synchronization is one of the most significant issues in femto-cellular networks to guarantee an acceptable clock offset and skew, which leads to severe int...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
Kuala Lumpur :
Kulliyyah of Engineering, International Islamic University Malaysia,
2012
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| Subjects: | |
| Online Access: | Click here to view 1st 24 pages of the thesis. Members can view fulltext at the specified PCs in the library. |
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| Summary: | Femtocell is a recently developed technology in cellular wireless network which extends to indoor coverage for serving a small number of users. Synchronization is one of the most significant issues in femto-cellular networks to guarantee an acceptable clock offset and skew, which leads to severe interference between femtocell BSs and/or between femtocells BS (fBS) and macrocell BSs (mBSs), where both are working in same frequency under a licensed spectrum. Usually, the femtocell is installed indoors, and has the limitation of Global Positioning System (GPS) antenna for time synchronization, so the traditional solution is using concurrent IEEE 1588 protocol or Network Time Protocol (NTP). However, these protocols are based on Transmission Control Protocol/Internet Protocol (TCP/IP) which is based on Internet cloud. Internet cloud does not guarantee stable traffic flow rate, hence the synchronization signalling face several challenges especially in the dense data traffic. In flat fBS structured network using IEEE 1588 synchronization algorithm and fBSfBS synchronization scheme creates offset error as well as frequency error which result in inaccurate synchronization. The necessity of time synchronization among femtocells triggers off the creation of interference leading to the clock offset which degrades the synchronization accuracy. The synchronization of carrier frequency/phase is required for implementing distributed solutions when more fBS are in the network. Some existing algorithms and schemes have been developed in order to synchronize the clocks which are mainly based on IEEE 1588 standard and involve direct synchronization processes through mBS, fBS-fBS synchronization schemes. However, an internal process is needed to enhance the synchronization during large network traffic and to reduce the signalling and traffic from/to IEEE 1588 servers. In this dissertation, cluster-based self-organized synchronization scheme is proposed which functions through clustering, intra-cluster and inter-cluster synchronization schemes. The proposed scheme provides high scalability and works in a decentralized manner which can support a large number of fBS networks with a satisfactory performance level in terms of synchronization accuracy. The proposed scheme is benchmarked with the mobile assisted fBS-fBS synchronization scheme. The analytical result shows for the proposed self-organized synchronization scheme, the inter-cluster synchronization accuracy of 52 % and 56 % for clock offset and clock skew is achieved respectively. It also shows that for the proposed cluster-based selforganized synchronization scheme, the intra-cluster synchronization accuracy up to 53.07% for clock offset and 60.32% for clock skew is possible. Both inter-cluster and intra-cluster synchronization accuracies are slightly higher than that of the mobile station assisted fBS-fBS synchronization scheme. |
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| Item Description: | Abstract in English and Arabic. "A dissertation submitted in fulfilment of the requirement for the degree of Master of Science (Communication Engineering)."--On t.p. |
| Physical Description: | xvi, 112 leaves : illustrations ; 30 cm. |
| Bibliography: | Includes bibliographical references (leaves 107-112). |