Tuesday, April 30, 2013

Development of small cells

Each wireless network is built out using many macro cell base stations, each covering a diameter of up to 3 kilometers and carefully located to minimize radio signal interference.  But the disadvantage of this topology is that coverage is not 100 percent. In order to increase the coverage small cells came into existence. The HetNet topology builds a network that includes existing macro cells and complements them with millions of smaller base stations, including micro cells and pico cells, appearing on lamp posts in urban areas and femto cells appearing in homes, residential high-rise apartments and businesses. The small cells provide a very efficient way to offload high traffic areas from the macro cells and therefore increase cell capacity and optimize spectrum utilization.
Today capacity, coverage and QoE expectations of the user has increased manifold. We need HetNet (heterogeneous networks) rather than macro-only networks to cope up with this growing demand. HetNet is a combination of wireless technologies and radio access options to cost effectively deliver higher throughput.  The key component of HetNet is small cells. Small cells are deployable anywhere both indoors and outdoors. Small cells solution is available for single home subscribers. Home subscribers experience better voice quality with no dropped calls due to dead zones, faster, more reliable data connections and higher data throughput. Small cell solutions are available for the enterprises, which helps extends better customer experience to the businesses. Small cells provide coverage and capacity for urban and rural hotspots. Small cells come with integrated Wi-Fi access points as well.
Small cells boost network capacity. If we move base station near to the UE the throughput and the reliability of the data connection will increase dramatically. Small cells have a flat IP architecture which helps us deliver a much better customer experience with low latency and higher speed. Small cells offer a cost effective solution to increase the coverage and capacity demands. Small cells offload traffic from the macro network which helps in increasing the network capacity without the deployment of new macro sites.
While there is extensive hype in the industry about “multi radio access technology (RAT), multi-vendor” type of HetNet solutions, the more imminent and practical solution is the interference avoidance required when small cells are rapidly added to existing LTE Macro centric networks. In order to resolve the interference problem 3gpp introduced inter cell interference control (ICIC) in Release 8 and more recently, in Release 10, the enhanced ICIC (eICIC) .
The SON standard is defined by the 3GPP and specifies algorithms to enhance the planning, deployment, operation and optimization of the network. Based on this standard, a SON algorithm will run upon startup of the small cells, allowing the device to insert itself into the network without interference. In terms of interference management, 3GPP introduced inter cell interference control (ICIC) in Release 8 and more recently, in Release 10, the enhanced ICIC (eICIC) standards. These standards are specified to mitigate interference in neighboring cells by using the power and frequency domains in the case of ICIC and adding the time domain for eICIC. Both standards rely on the X2 interface to exchange information between eNode B’s and typically require a client/server or hybrid deployment in order to perform the optimization and coordination functions.

Sunday, April 21, 2013

LTE: A boon or a boom.

With the advent of smartphones, tabs etc. there is a tremendous growth of data usage. The world is moving towards connecting everything from the household appliances to surveillance devices.      To add to this when everything is connected, intense pressure on the network is bound to happen. This manifold growth in data usage is both a challenge and an opportunity for the MNO’s. The major challenge for the operator is to gratify the growing hunger for data but the agony of the operator is that the bandwidth is a limited resource.
This exponential growth in data usage is a result of smart LTE compatible user devices which can consume huge data in no time. It has introduced a huge competition to capture the smartphones and tabs market. It is pleasing to have a smart device loaded with android or ios, which provides a whole bundle of innovative apps at your disposal. These apps keep you engaged and most of the times you end up being engrossed and hooked up. Today smartphone experience has revolutionizing the way telephony is looked at. People are using live streaming, YouTube and other data hungry apps which are bringing a toll on the network as well as the CSP’s.  Research shows that today connectivity has become a birthright of the user.
LTE is the answer to this churning by decreasing the latency and increasing the speed using OFDMA and optimized network elements. The recommended downlink speed for LTE is 100 mbps and for uplink it is 50 mbps.  LTE is a boon to the high tech industry. The beneficiaries are equipment manufacturers, over-the-top (OTT) service operators like Google, Microsoft, YouTube, Skype, etc. and Communication Service providers (CSP). But the industry is divided over the revenue sharing model. Many feel that this is a boom for the OTT service providers rather than network operators. Others have the view that MNO’s deserve a bite of the revenue generated by the OTT players. But I feel that this is indeed an opportunity for the stagnant telecom industry where the revenues were shrinking due to high competition and limited bandwidth. This is an opportunity for the industry to cash in the digital revolution. Everyone who helps to enhance customer experience should be benefitted. So I feel in spite of fighting over this trivial and useless issue network providers should continue providing dead pipe and OTT players should continue to provide innovative services.  MNO’s should think innovatively to increase the network capability further; ultimately they will be benefitted over a period of time. At the same time no one is stopping them to enter the OTT player’s arena.
LTE is an all-IP, data-only transport technology using packet switching. One challenge for the MNO’s is to satisfy the established quality of service for circuit-switched mobile for telephony and SMS for LTE capable smartphones, while being served on the LTE network. Due to incomplete LTE rollover, interoperability between legacy networks and LTE is also a biggest challenge. The dichotomy between packet switched data and circuit switched voice networks can be addressed by dual radio solutions or single radio solutions. Dual radio solutions use two always-on radios, one for packet switched LTE data and another for circuit switched telephony, and as a data fallback where LTE is not available. Single radio solutions use one radio to handle both types of traffic, and use network signaling to determine when to switch from the PS network to the CS network. This solution is universally accepted for LTE-3GPP network interworking solutions. This switch from the PS network to the CS network is called circuit-switched fallback (CSFB).   In CSFB, when the data session is active and a call comes in, the LTE network pages the device. The device responds with a special service request message to the network, and the network signals the device to move to 2G/3G to accept the incoming call. Similarly when an outgoing call is initiated, the same special service request is used to move the device to 2G/3G to place the outgoing call. CSFB addresses the requirements of the first phase of the evolution of mobile voice services in LTE. CSFB is the first step to enable mainstream LTE devices with the cost, size and battery life advantages of single-radio solutions to LTE data in combination with 2G/3G voice (and data fallback, in non-LTE areas). VoLTE is the most suitable and viable option over CSFB but VoLTE handsets will continue to require CSFB for roaming for quite some time. VoLTE need some time to become a natural choice but for that LTE needs to be ubiquitous.
The finesse of the LTE is yet to come after the blistering growth of LTE in the recent past. With the time investments in LTE network infrastructure will grow and so will the returns on the investment. Nevertheless there are many challenges; there is a solution to every problem and dispute. Everyone will contest for his share of the revenue and the only one who will benefit out of this tussle between OTT and Operators is the customer. Customer experience should be the driving force for all the stakeholders.