Telco provides instant Wireless E1 Service
Wireless is easily the lowest cost and most easily implemented solution today for the increasing backhaul demands for a Telco's network. When a Telco in Pakistan needed to extend E1 lines to reach a customer, it chose a wireless backhaul to avoid laying cable for a single link. Worldcall, one of Pakistan's largest private telecom operators, decided on smartBridges Nexus backhaul to extend the E1 lines to the leading GSM cellular operator in Pakistan with over 17 million subscribers.
The wireless link, implemented by NetSoft Solutions, smartBridges Channel Partner in Pakistan, connects the customer's office to Worldcall premises in Lahore. By choosing a wireless link in the unlicensed band, Worldcall achieved immediate deployment and hence immediate revenue realization while keeping Capital Expenditure (CAPEX) and Operating Expenditure (OPEX) to a minimum.
E1 is a TDM (Time-Division Multiplexing), a physical layer protocol used for leased line transmissions. It can carry either voice or data traffic or both. Each E1 line has 32 individual timeslots of 8 bits each, thereby giving an E1 frame 256 bits. The data rate of a timeslot is 64 Kbps resulting in 8,000 frames a second (64,000/second/8 bits). The E1 frame arrives every 125 microseconds (1 second/8000 frames/second) so the line rate will then be 2 Mbps (32 channels x 8 bits/channel)/ frame x 8000 frames/second). For two way traffic, it will be double that.
Diagram showing the E1 frame with 32 timeslots
Timeslot 0 is used for frame synchronization, without which data recovery at the receiver end would not be possible. Using a TDMoIP (TDM over IP) multiplexer device, the traffic carried by the E1 trunk is enabled for transport through an Ethernet infrastructure. But without the Nexus radios' low latency and jitter control features, the clock synchronization would not be maintained and the subsequent clock drift would prevent a successful wireless transmission. The field proven real time prioritization of traffic and Quality of Service (QoS) features of the Nexus Platform allows traffic from each individual timeslot in an E1 line to be transmitted wirelessly without loss of quality.
The wireless link interfaces with the two E1 lines through the TDMoIP multiplexers
In the actual deployment, two E1 lines from Worldcall's network are fed to a E1 over Wireles multiplexer to convert it to an Ethernet packet. The Ethernet line connects to the airHaul Nexus radio which transmits it "effectively" in the 5.8 GHz band to the remote device at the customer's end which has a TDMoIP de-multiplexer to convert the signal back to an E1 frame.
The smartBridges radios and antennas are installed on a 110 ft (33 m) tall tower on top of Worldcall building and a 200 ft (60 m) tower at the customer's site. Using smartBridges 29 dBi antennas, the 7.6-mile-long (12 km) link achieves 8 Mbps of stable throughput despite the high interference in such a built-up area. The link is mainly used for data connectivity.
Athar Sabir, Business Development Manager at NetSoft, remarked, "The low latency and high throughput of the Nexus Platform make it suitable for extending the reach of high bandwidth leased lines such as E1. It allows for various applications like GSM support, connection to a PABX system, providing Internet as well as data connectivity, depending on the needs of the customer. The combination of wireless and leased lines in this deployment gives an unbeatable price-to-performance ratio and we are looking to duplicate the success."
About Netsoft
NetSoft provides comprehensive solutions for the enterprise in (WAN) connectivity, for either a single office setup or a chain of offices dispersed around the globe. They build solutions to help enterprises manage networks of any size and configuration easily and conveniently. For more information, please visit their website.
About Worldcall
