Cluster-based Multihop Synchronization Scheme for Femtocell Network

Authors

  • Aisha H. Abdalla International Islamic University Malaysia
  • Rashid A. Saeed International Islamic University Malaysia
  • Mohammad K. Hasan International Islamic University Malaysia
  • Shayla Islam International Islamic University Malaysia
  • Othman O. Khalifa International Islamic University Malaysia

DOI:

https://doi.org/10.31436/iiumej.v13i2.310

Abstract

ABSTRACT: Femtocell technology has been drawing considerable attention as a cost-effective means of improving cellular coverage and capacity. It is connected to the core network through an IP backhaul and can only use timing protocols such as IEEE1588 or Network Time Protocol (NTP). Furthermore, the femtocell is installed indoor, and cannot use a GPS antenna for time synchronization.  High-precision crystal oscillators can solve the timing problem, but they are often too expensive for consumer grade devices. Therefore, femtocell Base Station (fBS) synchronization is one of the principle technical trends in femtocell deployment. Since fBSand macrocell Base Station (mBS) network operates on the same frequency under a licensed spectrum, fBS network can interfere with the macrocell network. In addition, fBSs can also interfere with each other if multiple units are in close proximity. Furthermore, in a flat fBS structured network using IEEE 1588 synchronization algorithm and fBS-fBS synchronization scheme creates offset and frequency error which results inaccurate synchronization. In order to reduce offset and frequency error (skew), this paper proposed a cluster-based multihop synchronization scheme to achieve precise in fBS neighbor nodes. The proposed scheme is able to reduce the offset and skew significantly.

ABSTRAK: Teknologi Femtocell telah menjadi tumpuan sebagai alat yang kos-efektif dalam memperbaiki liputan mudahalih dan kapasiti. Ia menghubungkan jaringan teras melalui IP backhaul dan hanya boleh menggunakan protokol masa seperti IEEE1588 atau Protokol Jaringan Masa (NTP). Seterusnya, femtocell dipasang di dalam, dan tidak boleh menggunakan antena GPS untuk sinkronisasi masa. Osilator Kristal yang tinggi kejituannya boleh menyelesaikan masalah masa, tetapi ianya mahal bagi gred peranti consumer. Oleh itu, sinkronisasi Stesen Asas femtocell (fBS) adalah salah satu tren teknikal prinsip dalam deployment femtocell. Memandangkan fBS dan jaringan Stesen Asas makrosel (mBS) beroperasi pada frekuensi yang sama di bawah spektrum lesen jaringan fBS boleh mengganggu jaringan makrosel. Tambahan pula, fBS juga boleh mengganggu antara satu sama lain jika unit pelbagai adalah close proximity. Tambahan lagi, bagi struktur jaringan rata fBS menggunakan algorisma sinkronisasi IEEE 1588 dan skema sinkronisasi fBS-fBS mencipta offset dan ralat frekuensi yang menyebabkan ketidaktepatansinkronisasi. Bagi mengurangkan offset dan ralat frekuensi (skew), kajian ini mencadangkan multihop berasaskan kluster skema sinkronisasi bagi mencapai kejituan dalam mod kejiranan fBS. Skema yang dicadangkan boleh mengurangkan offset dan skew dengan berkesan.

KEYWORDS: femtocell base satationt (FBS); synchronization; frequency division multiple access (OFDMA); inter-cluster, intra-cluster

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Author Biographies

Aisha H. Abdalla, International Islamic University Malaysia

Electrical and Computer Engineering Department

Kulliyyah of Engineering

Rashid A. Saeed, International Islamic University Malaysia

Electrical and Computer Engineering Department

Kulliyyah of Engineering

Mohammad K. Hasan, International Islamic University Malaysia

Electrical and Computer Engineering Department

Kulliyyah of Engineering

Shayla Islam, International Islamic University Malaysia

Electrical and Computer Engineering Department

Kulliyyah of Engineering

Othman O. Khalifa, International Islamic University Malaysia

Electrical and Computer Engineering Department

Kulliyyah of Engineering

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Published

2012-10-12

How to Cite

Abdalla, A. H., Saeed, R. A., Hasan, M. K., Islam, S., & Khalifa, O. O. (2012). Cluster-based Multihop Synchronization Scheme for Femtocell Network. IIUM Engineering Journal, 13(2). https://doi.org/10.31436/iiumej.v13i2.310

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Articles