Impact of twisting rate in 10 pairs of unshielded twisted-pair copper cables on insertion loss and crosstalk coupling for G.fast technology

Saizalmursidi Md Mustam,Mohammad Arif Ilyas,Che Ku Afifah Che Ku Alam,Muhammad Syukri Mohd Yazed

doi:10.11591/eei.v9i2.1873

Abstract

An ultrafast digital subscriber line (DSL) technology called G.fast is important for ultrafast broadband Internet access services. In G.fast, the existing cable bundles installed for 250 m from the distribution point to the customer’s premises are used to support the gigabit data transmission (aggregated 1 Gbit/s) for frequency up to 106 MHz or 212 MHz. Since unshielded cable is used, and the frequency is 12 times higher compared to the very high-speed DSL2 (VDSL2), it is important to investigate the cable performance in terms of insertion loss and crosstalk coupling. In this paper, the impact of cable twisting rate on 10 pairs of unshielded twisted-pair copper cables for a small copper bundle on insertion loss and crosstalk coupling is investigated. A simulation model is developed based on the standard cable installed in Malaysia. The model reliability is validated by comparing the obtained result with the published result in the literature. Besides, the twisting rate of 100 m cable is manipulated by changing its lay size to determine its impact on insertion loss and crosstalk coupling. The results showed that a high twisting rate can reduce the far-end crosstalk but increase both the insertion loss and near-end crosstalk.

Highlights

In the telecommunication industry, the digital subscriber line (DSL) technology via twisted-pair copper cables plays a vital role as an infrastructure for high-speed Internet access as well as for worldwide information technology connectivity, especially for suburban areas
The standardization work on DSL technology was initiated by the International Telecommunication Union-Telecommunication Standardization Sector (ITU-T) Study Group 15 (SG15) in 1998
This technology is further improved to high-bit-rate DSL (HDSL) in 1998, to asymmetric DSL (ADSL) in 1999, to ADSL 2 (ADSL2) in 2002, to ADSL 2+ (ADSL2+) in 2003, to very high speed DSL (VDSL) in 2004, to very high-speed DSL2 (VDSL2) in 2006, to VDSL2 with vectoring (VDSL2 vectoring) in 2010 and the latest is ultrafast DSL called gigabit fast access to subscriber terminal (G.fast) in 2014 [4,5,6]

Summary

Introduction

The DSL technology via twisted-pair copper cables plays a vital role as an infrastructure for high-speed Internet access as well as for worldwide information technology connectivity, especially for suburban areas. G.fast technology can support data transferring up to 1 Gbps that is similar to data transmission rate over the fiber cable (optical transmission) [7,8], the maximum bandwidth of around 106 MHz or 212 MHz and the transmission distance up to around 250 m from the distribution point DP to the subscriber's premise [9,10,11] This technology provides a hybrid method to telecommunication service operators, where the connectivity after the DP is completed by utilizing the existing twisted-pair copper cable that is previously used for a phone line and ADSL2+ [9]. Crosstalk coupling among multiple unshielded twisted-pair copper cables in a cable bundle has been found as the most significant interference [12, 13] in VDSL2 system which operates with a maximum bandwidth of 30 MHz [14]

Methods

Results

Conclusion