RAD Releases Vmux-400 A-bis Gateway; Offers Up to 3:1 Optimization of BTS-to-BSC Backhaul Traffic

RAD Data Communications announced the release of the Vmux-400 A-bis optimization gateway, which enables mobile operators to cut bandwidth requirements and reduce Opex and Capex on base transceiver station (BTS) to base station controller (BSC) cellular backhaul. When used in conjunction with RAD’s Vmux voice compression gateways, it offers cellular operators a comprehensive, single-vendor solution for dramatically maximizing bandwidth utilization and reducing transport costs across the entire GSM backhaul route. Industry experts estimate that backhaul accounts for 40 to 60 percent of operating expenses in the radio transport network.

A-bis optimization involves eliminating redundant silence and idle frames in the A-bis protocol, which contains the compressed voice payload along with signaling data in the BTS-to-BSC segment of the mobile network. Moreover, the E1 lines coming from the BTS are typically underutilized. The Vmux-400 can achieve an optimization ratio of up to 3:1 (depending on the periods of call silence and the signaling) by also connecting the partially used E1 links to its two E1 ports and multiplexing the traffic into a single E1 uplink for transport to the BSC.

 

“For cellular operators which rely heavily on TDM leased lines from terrestrial carriers, this means that the number of links needed for A-bis backhaul can be cut in half, with a corresponding impact on cost reduction” says Toby Korall, Vmux Product Line Manager at RAD Data Communications. In areas where landlines are not an option, satellite or microwave radio links may be employed for backhaul. “These are relatively expensive connections,” explains Korall. “The Vmux-400 is particularly beneficial in these applications, reducing bandwidth requirements significantly and ensuring a rapid return on the operator’s investment,” continues Korall. The Vmux-400 is also relevant for mobile operators in their migration to 3G, since optimization enables operators to free up leased lines used for 2G/2.5G traffic and apply them to their 3G networks. “In this way, they can avoid the time delay and costs associated with installing additional leased lines,” opines Korall.

The compact, half 19-inch wide Vmux-400 comes equipped with an E1 network link, an n x 64 kbps serial port and an IP/Ethernet uplink (a unique feature allows for reliable regeneration of the TDM-based clock to synchronize network operation and permits packet switched networks to be used for transport of cellular voice traffic). This versatility gives operators the flexibility to choose the most efficient and cost-effective network for backhauling their BTS traffic. It also means that operators don’t have to swap out equipment when migrating from a TDM to a packet switched transport network.

The Vmux-400 supports transparent data, GPRS and EDGE over multiple timeslots for transmission in GSM networks as well as standard GSM A-ter optimization and AMR codec rates from 4.75 to 12.2 kbps. The standards-based Vmux-400 is interoperable with equipment from major switch vendors, such as Alcatel, Nokia, Ericsson, Siemens, Huawei, and Motorola, facilitating connectivity in multi-vendor environments.

While the Vmux-400 optimizes the A-bis (BTS-to-BSC) interface, the

Vmux-2100 voice trunking (compression) gateway, delivering a voice bandwidth compression ratio of up to 16:1, can optimize both the A (BSC-to-MSC) and E (MSC-to-PSTN) interface. Together, they can significantly reduce transport costs for network operators across the entire GSM backhaul route.