Future of Multicast & Broadcast Services in Wireless Networks

With the evolution of Smartphone and exponentially growing market for high speed multimedia services the network needs to be smarter for delivering an exhilarating user-experience. .The transformation of mobile devices industry led by advent of successful smartphones such as Blackberry, Apple iPhone the users have become more data hungry and demanding more interactive services loading the mobile network operator’s network.Multicast and Broadcast services (MBS) is the solution that will not only cater this need efficiently but also attract a large subscriber base. MBS offers real time streaming services, audio-video on demand, multiplayer online gaming, localized services, news advertisements, stocks bringing the most anticipated services at your finger tips.

MBS in 3rd Generation and 4th Generation Wireless systems requires efficient network resource utilization in access and core networks along with scalable and reliable service platforms. Also, it should incorporate the mobility aspects to continuously deliver multimedia information over an efficient air interface.

The major MBS technologies used in various 3G/4G deployment models are Media FLO by Qualcomm, DVB-H (Digital Video Broadcasting-Handheld) by DVB, MBBS by 3GPP and BCMCS by3GPP2. These technologies have garnered much attention for the revenues they can bring to terminal suppliers, network equipment suppliers, mobile operators, broadcast operators, service providers and even governments.

The main analysis considering the different old as well as new evolving use cases with the MBS technologies supporting these different services can be mapped as follows:

Considering the above use-cases we can draw insights:

1. Selection: The selection of particular MBS technology by the mobile network operator should be based on following criteria

2. Cost: For heavy duty broadcast applications the resources required would be greater in a 3G network compared to a Broadcast only network such as MediaFLO or DVB-H and hence the cost.
Whereas for light applications and highly interactive applications MBMS or BCMCS would be the ideal choice saving on resources by multicasting to the subscribed group of users instead of broadcasting it to every user in the network. Also, due to availability of an uplink channel, highly interactive applications can be easily supported on the mobile terminal providing a better user experience. Also, from unicasting perspective, with Multicast usage there is a considerable resource savings in core network and radio access network where the radio bearers are lesser than number of users compared to the number of bearers which is equal to number of users in unicast transmissions

3.Reach: MediaFLO and DVB-H have a larger cell size and hence a larger footprint which again thus requires lesser base stations covering groups of subscriber services. But again due to the existing vast coverage of the 2G/3G cellular network, these base stations can be easily upgraded to MBMS/BCMCS capabilities with a comparatively greater reach though smaller individual footprint.

4. Interactivity: Broadcast only networks are limited due to the lack of backward channel and hence no interactivity. But the interactivity can be implemented by using network operator’s feedback channel.

5.Mobile Terminal: In the current scenario, for specific applications such as Live TV, broadcast only technologies like MediaFLO or DVB-H might prove to be more efficient but the downfall is the corresponding handsets should be available to receive such broadcasts so that is an additional cost to the MNO’s.

6.Business Implicaitons: The broadcast and multicast are complimentary technologies where broadcast can be used for stimulating users to subscribe to the services and multicast services are used to cater specific endusers which eventually subscribes t ospecific services which generate revenues for the operators.

7.Mobile Trend: There is a significant growing trend towards a large number of interactive applications with the advent of modile web due to the availability of smartphones with a larger form factor and advanced capabilities. So most of the NGN will be equipped with cutting edge resource efficient technologies supporting heavy duty streaming and at the same time supporting a higher level of interactivity and a richer user experience with a better continous data connectivity and seamless mobility

Thus with a strong MBS technology selection by the MNO and a lucrative business model a smart telecom value chain is possible and with higher order benefits.

HSPA, EVDO, WiMax then LTE but what about the mobile backhaul??

With HSPA, EVDO maturing, WiMax getting deployed and LTE getting ready to buzz around, it is soon changing the way mobile phones will access the networks. The bandwidth hungry new services, applications and the non-stop touch clicks on your smart handhelds are eventually going to obsolete these mature 3G networks. Whereas, the 4G access networks are definitely envisioned to control this ever-increasing wireless broadband traffic but what bout the evolution of backhaul?? Is it ready? or is it going to be a major bottleneck analogous to the traffic jams seen if only one lane was operating out of a four lane expressway.

So, let’s have a closer look on how the mobile backhaul network is currently positioned.

The trend below depicts the exponential growth in asynchronous data demand for next 5 years.

Mobile Traffic Projections for the next 5 years

Over the next few years, “user experience” will still continue to rely on 3G (and in some regions on 2G) technology.But for the mobile operator, LTE/WiMax is already part of the game plan. Operators have to learn the technology, and its impact on their networks, applications and service offering. Though, service providers are seeking revenue and profit growth through new differentiated packet-based services. Many of these services, such as mobile Internet and mobile TV, require high bandwidth—and the current backhaul infrastructure is not optimized for handling such traffic. Hence, providers have to add backhaul capacity while keeping operational costs under control, a situation that is forcing carriers to migrate their access and core networks to the new 3G and 4G infrastructure.

There are three main transport technologies in the backhaul arena – fiber, copper and wireless point-to-point microwave.

The costs of backhaul form a significant part of service providers’ revenue accounting for three quarters of mobile transport costs and 25-30% of total operating expenses. The 2G infrastructure carried voice traffic through switched TDM (T1/E1 or SDH/SONET) or ATM. As with 3G/4G services, already  the bandwidth requirements have shot exponentially and to transport voice and data efficiently has been the need of the hour.

Basic requirements for a 4G Backhaul network:

1. Capacity: A single tail site should be scalable to 100Mbps+ capacities to avoid bottlenecks

2. Latency: A solution that supports 10msec or less end-to-end latency

3. All IP: Support IP traffic from head to tail.

Current migrating strategy is transporting Ethernet packets over point-to-point Microwave. Over 50% of all mobile backhaul deployments worldwide (and nearly 70% outside the U.S.A.), point-to-point microwave systems offer simple and cost efficient backhauling for voice and high-speed data services. That’s because point-to-point microwave supports higher data rates than traditional copper T1/E1 lines, it delivers between 25% and 60% more bits compared with similar TDM based systems, and easily overcomes the high cost and limited availability associated with fiber. Thus, operators can connect the TDM ports today, and gradually shift traffic to the Ethernet ports in the future. This shift can be done from remote, so no additional CAPEX or OPEX are needed. The industry has already established that the end game of next generation mobile backhaul networks is all-IP/Ethernet. Ethernet is not only more scalable, it also offers huge cost savings across the entire network value chain.

Ethernet cost savings per 1 Million subscribers

Also migrating to high capacity and lower latency Ethernet/All IP network, the systems should also support QoS aware Adaptive Coding and Modulation and Statistical Multiplexing. The former helps optimizing network for spectrum efficiency, increasing the radio capacity and  thus reducing cost/bit and latter in optimizing traffic management over the network reducing congestion and improving efficiency. An IP over Ethernet infrastructure has the advantage of the bandwidth growth curve of Ethernet moving from 10 Megabits per second (Mbps) to 10 Gigabits per second (Gbps) today and 100 Gbps in future. This coupled with the decreasing cost of Ethernet ports provides growth opportunities with increasing economies of scale.

Ethernet microwave Vs. TDM microwave equipment cost comparison

Thus, of the three backhaul technology options operators can choose from, wireless point-to-point microwave can deliver the best cost-performance features, bringing faster ROI and driving forward the proliferation of advanced mobile services in the LTE/WiMax era. But in the longer run a hybrid  solution of microwave, optical or IP/MPLS core might be seen as a balanced solution that might reduce the OPEX with improved scalability, higher bandwidth, lower latency and better efficiency. So operators pull up the socks and get ready for the great migration.

Also, a point to note with CISCO’s recent acquisition of Starnet Networks which makes it now one of the most dominant player in mobile backhaul solutions market.

From the recent news releases:

Verizon has committed to deploying fiber to 90% of the cell sites in its territory by 2013, closely following VZW’s LTE rollout schedule

Qwest plans to run fiber 7,500 to 17,000 cell sites in its territory

- Neil Shah

References:

“ATM to ALL IP”  Cost effective Network Convergence – Tellabs ’2009.

“LTE Backhaul Solutions”- Ceragon June 2009

Cable Backhaul: A towering OpportunityWebinar Harris Stratex Networks Nov’2009