Power Architecture Enabled Differentiated Solution for LTE

By Fawzi Behmann

This article is intended to provide status on LTE as a key technology enabler that will have impact on the entire telecom supply chain. LTE impact affects semiconductor SoC, communications networking infrastructure, mobile devices, applications and quality services transforming means of communications to a new level – higher speed, multimedia content and enriching personal experiences. The article will cover a number of important topics covering the needs for LTE, LTE market positioning and benefits, LTE market trends, deployment and applications, and LTE roadmap. The article will conclude with how Power Architecture technology is enabling differentiated solution for LTE.

Needs for LTE, Positioning and Benefits
Needs for LTE
Text messages sent and received via mobile devices have exceeded the population of the planet. The emergence of the iPhone and other Internet and multimedia-enabled smart phones have shown the potential of mobile data services beyond that of simple text messaging and emails and has dramatically driven exponential mobile data traffic growth. The average smart phone user generates 10 times the amount of traffic generated by the average non-smart phone user. As a result, mobile data traffic is growing at a rate of 40% per year. Currently, some service providers are challenged in building out their 3G wireless infrastructure quickly enough to keep up with the demand generated by smart phone users. Hence, the aggressive industry push for LTE (Long Term Evolution) to accommodate huge traffic growth and for LTE to become essential to take mobile broadband to the mass market.

LTE market positioning and benefits
Carriers are considering LTE deployments in the emerging regions where mobile Internet is becoming a real fixed line alternative. LTE is likely to begin its life cycle with data cards and connectivity modems. Upgrade to existing 3G networks will lead to a smoother transition to LTE.

LTE will provide the reduced latency, increased peak bandwidth, and greater network capacity required for the advanced voice, data, and video applications made possible by the latest mobile phones. HD video, which the iPhone 4 supports, is only the latest in a stream of new applications that will stretch 3G networks to the breaking point. LTE is backward compatible with existing solutions, and it will meet the long-term needs of carriers and their customers for high-speed data traffic supporting Internet browsing, voice, and video.

LTE Market Trends, Deployment
LTE Market Trends
The LTE infrastructure market is expected to reach $11.4 billion by 2014 (Infonetics Research, April 2010) and analysts expect 136 million LTE subscribers (Pyramid Research, May 2009) paying $70 billion in service revenue (Juniper Research); an average of $42 per subscriber per month. LTE is expected to grow rapidly from 2013 onward.

Carrier commitment to LTE continues to grow. According to the Global Mobile Suppliers Association (GSA), there are now 110 operators across 48 countries committed to LTE. By the end of 2010, 22 LTE networks are expected to be operational, and more operators will be evaluating LTE.

LTE Deployment
2011 will be the year when LTE goes live in a big way, as Verizon in the United States and DoCoMo in Japan will begin wide-scale roll-outs by the end of 2010. 132 networks have reported trials or plans to launch LTE commercially, 32 more than the end of 2009. Verizon has also hinted at the availability of LTE-based handsets by May 2011. AT&T plan to begin LTE trials in the next few months and will start commercial service in 2011.

As of Q2, 2010, LTE scorecard shows:

  • Global acceptance by leading operators worldwide (GSM/HSPA operators, leading CDMA operators, and a leading WiMAX operators)
  • Infrastructure systems are shipping and being installed
  • Spectrum is available to support initial system deployments
  • LTE is launched commercially in two countries Norway and Sweden and is poised for significant expansion in 2010/2011 to 110 LTE networks in 48 countries

LTE Roadmap
3GPP LTE is an evolution of the GSM/UMTS (comprising WCDMA, HSPA), and specifies the next generation mobile broadband access system. LTE will be conforming to Release 9 of the 3GPP (frozen end of 2009).

Specification for LTE downlink speed is 150Mbps compared to 21-84 Mbps for HSPA+, 14.4 Mbps for HSPA and 384 Kbps for 3G/WCDMA.

3GPP LTE evolution
Source: GSA

According to ITU’s definition of 4G, requirements include average downlink speeds of 100 Mbps in the wide area network, and up to 1Gbbs for local access or low mobility scenarios. Next generation LTE (LTE Evolution) will address the target of 1Gbps downlink speed.

Throughout 2009, 3GPP has worked on a study to identify the LTE improvements required by ITU IMT-Advanced. A major reason for aligning LTE with IMT-Advanced is to ensure that today’s deployed LTE mobile networks provide an evolutionary path towards many years of commercial operation.

LTE utilizes a new state-of-the-art radio air interface technology known as Orthogonal Frequency
Division Multiple Access (OFDMA) to provide several key benefits including significantly increased peak data rates, increased cell edge performance, reduced latency, scalable bandwidth, co-existence with GSM/EDGE/UMTS systems, reduced CAPEX and OPEX.

LTE is also scalable to allow operation in a wide range of spectrum bandwidths, from 1.4 – 20 MHz, using both Frequency Division Duplex (FDD) and Time Division Duplex (TDD) modes of operation, thus providing flexibility to suit any carrier’s existing or future frequency allocation globally.

Power Architecture differentiated solution for LTE
LTE Requirements
Requirements for LTE infrastructure providers are a system architectures that will simplify and reduce the cost of network roll-out and management. This implies that the costs of both silicon and software development must decrease dramatically. In addition, power constraints become primary consideration imposed by densely packed infrastructure components. The cost, programmability, and power requirements directly affect silicon providers.

For silicon providers, this translates to enabling more processing in parallel using multicore systems. In addition to the bandwidth and power requirements, advanced network and application features continues to increase, demanding increasingly powerful processor cores to sustain system throughput goals. For these reasons, LTE views both system throughput and single-thread processor performance as key metrics. As a result, the silicon roadmap to support LTE must satisfy extremely rigorous demands for high levels of on-chip and chip-to-chip integration within tight power budgets.

Differentiated Solution based on Power Architecture
The requirements of LTE are best satisfied using a systems-oriented solution in the form of a heterogeneous system-on-chip (SoC), including a scalable set of multicore processors and applications-specific accelerators such as pattern matching engines, security engines, packet processing engines and other features to improve overall system performance, programmability, and power efficiency. This type of solution requires that the processor cores be designed from the start to integrate well, to scale to meet performance requirements in multicore configurations, and to be power efficient.

Embedded Virtualization
The key advantage of embedded virtualization is to provide I/O virtualization to enable sharing and management of hardware accelerators. The hypervisor is a true hardware-supported operating mode that ensures protection of the virtual kernel from guest operating systems. Thus, the hypervisor allows different software systems to run on different cores at the same time with high integrity. This approach allows each software system and its associated private hardware resources to be protected from interference from the others.

Multicore Efficiency
LTE requires numerous system-wide statistics to be maintained across many threads of computation. If such counters are implemented as shared memory locations, then access to them must be controlled to prevent race conditions. In software, this synchronization can lead to serious performance degradation because of the time required to obtain a semaphore before accessing and updating the statistics counter.

Power Architecture supports efficient interaction with shared statistics counters and with hardware accelerators using decorated load and store instructions. These instructions allow efficient three-operand (address, data, command) that replace a series of transactions between cores and memory or between cores and accelerators with highly optimized transactions.

Power Management
Power Architecture cores provide important capabilities for dynamic power management. Some of these are enabled internally in the core. Furthermore, Power Architecture cores offer software-selectable power-saving modes. These power-saving modes reduce function in other areas, with some modes limiting cache and bus-snooping operations, and some modes turning off all functional units except for interrupts. These techniques are an effective way to reduce power, because they reduce switching on the chip and give operating systems a means to exercise dynamic power management.

Quality Software
A large portion of the time required to develop products using embedded multicore processors is spent on testing and optimizing application software. Sophisticated heterogeneous SoCs require powerful debug and runtime support as well. To meet that need, Power Architecture multicore SoCs support standardized debug, performance monitors, load spreading, device virtualization, and virtualization with real applications. They have an outstanding ecosystem. Time-to-market is greatly affected by software development effort as well. Power Architecture’s community is addressing this impact by providing vertical solutions for market segments such as the LTE segment. For example, Freescale’s VortiQa solutions speed development by providing fully integrated, architecturally compatible application software. VortiQa software is optimized to take full advantage of Freescale’s heterogeneous SoC architectures, including pattern matching engines, security accelerators, data path accelerants and other features, thereby boosting performance in embedded systems.

Power Architecture cores are suitable for high levels of heterogeneous integration using multiple cores and various hardware accelerators providing cost-optimized solutions that meet performance and power goals for LTE.

For further details on Power Architecture differentiated solution for LTE, please visit whitepaper on Power Architecture Competitive Differentiation – Wireless Access (pdf).

This article was written by Fawzi Behmann of Power.org