OnQ Blog

Carrier Aggregation: Can 1+1 > 2?

23 de sep. de 2013

Qualcomm products mentioned within this post are offered by Qualcomm Technologies, Inc. and/or its subsidiaries.

I know it indeed is cliché! But, I can’t help it, because it is true! I am talking about LTE Advanced carrier aggregation. Carrier aggregation is an important step of LTE Advanced. Its first incarnation—aggregation across two 10 MHz carriers—was launched in June 2013. This launch was powered by Qualcomm Snapdragon 800 chipsets with integrated third-generation Gobi LTE modems.

Carrier aggregation is a simple concept: you bond multiple carriers together, so you get more resources per user and hence better data rates and user experience. In a way, it’s “the more, the merrier”—the more carriers to bond, the more resources to the user and hence, higher the performance. LTE Advanced theoretically allows aggregating up to five carriers, yielding peak date rates of more than 1 Gbps.

The first step, obviously, is bonding two 10 MHz carriers on the downlink, as done in the aforementioned launch, enabling a peak data rate of 150 Mbps (Cat 4 devices). But more importantly, this doubles the data rates for users across the cell coverage area, meaning  the data rates that users get are twice those obtained in a single carrier case, whether they are close to the cell or at the cell edge. So, users don’t have to keep moving around, looking at the “bars” on their phones, to get higher speeds.

Increased data rate is straight forward enough. But the next benefit that I will explain is not that obvious, so pay attention! Under typical loading conditions, the increased data rate can be traded off to get twice the capacity or more, on a per-carrier basis for bursty applications such as smartphone usage, social media apps, instant messaging, browsing and others. This means, the overall capacity doubles when you go from two un-aggregated carriers to the same two carriers aggregated. You ask me “How?” Well, the magic term is “trunking efficiency.”

Additionally, carrier aggregation is going to be a crucial tool for operators to utilize the entire available spectrum. As evident, operators will have spectrum in various bands with varying bandwidth. Carrier aggregation will be a glue to bind all of them together. Looking at the possibilities, it is very clear that carrier aggregation will evolve in many directions in the future. There could be aggregation across more carriers, more band combinations—more than 45 being defined in 3GPP. There will be many different kinds of aggregations: SDL (Supplemental Down Link)—aggregating paired and unpaired spectrum; uplink aggregation; MultiFlow—aggregation across cells; aggregation across LTE FDD and TDD, and more

To all the skeptics, asking how will carrier aggregation prosper, my answer is “Go checkout how quickly HSPA+ dual-carrier became mainstream after its first launch.” The case for LTE Advanced carrier aggregation is even stronger, considering the vastly fragmented spectrum bands across the world. So sit tight, and see the places carrier aggregation will go in the future. Meanwhile, if you would like to know more, please visit our dedicated webpage, www.qualcomm.com/ca.

Prakash Sangam

Director, Technical Marketing

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Cellular V2X is gaining momentum

Believe it or not, the idea of talking cars on our streets and highways everywhere just got one step closer to reality.

Yesterday, the 3GPP announced the completion of the initial Cellular V2X (C-V2X) standard, which focuses on V2X Direct Communication. Further enhancements to support additional V2X operational scenarios will follow in 3GPP Release 14, targeted for completion in March 2017. In addition, today, key auto and mobile industry players including Audi AG, BMW Group, Daimler AG, Ericsson, Huawei, Intel, Nokia and Qualcomm Incorporated, announced the formation of the global, cross-industry 5G Automotive Association (5GAA). One of the key objectives of the association is to develop, test and promote communications solutions, such as C-V2X communication and its strong evolution to 5G. The Association is creating real cross-industry momentum around the development and deployment of connected car technologies, working to support national and regional policies in Europe and globally.

The completion of the initial C-V2X specification in 3GPP represents an incredibly important milestone for the role of the cellular ecosystem in vehicular communications. C-V2X is becoming a viable modern alternative to IEEE 802.11p and the basis for significant advancements in the future as the cellular industry moves toward 5G.

George Tsirtsis, Qualcomm Technologies C-V2X Engineering Lead

In my last blog post I covered how C-V2X was introduced in 3GPP Release 14 by evolving LTE Direct and LTE Broadcast to meet the requirements for automated driving. C-V2X will serve as the foundation for the safe, connected vehicle of the future, giving vehicles the ability to communicate with each other (V2V), with pedestrians’ devices (V2P), with roadside infrastructure (V2I) and with the cellular network (V2N).

C-V2X defines two new transmission modes that together enable a broad range of use cases:

  • C-V2X Direct communications – Enhances LTE Direct device-to-device communications to enable direct exchange of real-time information between vehicles, road side infrastructure and/or pedestrians’ devices.
  • C-V2X Network communications - Leverages existing LTE infrastructure with ubiquitous coverage to bring additional services, such as finding parking or advanced accident alerts

The coexistence of the two modes of operation delivers more advanced deployment scenarios and services to vehicles, opening up new opportunities and diverse business models for operators.

In this post, I want to elaborate on why C-V2X is gaining momentum and support from key global industry players:

1) Strong ecosystem – C-V2X benefits from the fast-moving and established mobile industry

The mobile ecosystem moves quickly to meet customer expectations, while keeping backward compatibility in mind. The fast evolution and high penetration rate of mobile devices have resulted in accelerated innovation and faster adoption of new technologies. The timely completion of the initial C-V2X standard is a testament to the fast pace of innovation in the mobile industry. This uptick in pace is penetrating the automotive industry, enabling a growing set of use cases for the connected vehicles and automated driving. The collaboration between the mobile and automotive industry has been established and the 5GAA will further foster this collaboration.

2) Superior performance – Designed to operate with or without cellular network coverage

C-V2X Direct communications enhances LTE Direct device-to-device communications with innovations to exchange real-time information between vehicles traveling at high speed, in high-density traffic, and even outside of mobile network coverage areas — enabling safer driving through true direct communications on designated ITS spectrum.

Several innovations have been introduced to allow direct V2X communication in the absence of infrastructure (i.e., without cellular network coverage). For example, the standard allows scheduling resources and interference management of V2X traffic based on distributed algorithms implemented between vehicles without network assistance. Also, vehicles can use Global Navigation Satellite System (GNSS) receivers for synchronization instead of relying on cellular network coverage. When in coverage, V2X Direct Communication can be augmented by V2N’s extended range and network assistance. 

All these enhancements result in dramatic performance improvements over those enabled by IEEE 802.11p-based systems, with the ability to operate at higher relative speed up to 500 km/h and at higher node densities.

3) Strong evolution path – Continuous enhancements to accommodate new use cases

Unlike older V2X technologies, C-V2X has a technology evolution roadmap, providing a unified connectivity platform for safer vehicles of tomorrow. The C-V2X roadmap will benefit enormously from the strong LTE evolution path and the introduction of 5G technologies in the coming years, and from the mobile ecosystem as a whole. The evolution of C-V2X is already being discussed and we envision a growing set of use cases, including ultra-low latency vehicle platooning, high throughput sensor sharing, video see-through, and other automated driving requirements.

Qualcomm is driving C-V2X on the path to 5G

We are very pleased to see these positive developments. Our unique position at the intersection of the automotive and communications industries allows us to pave the road to our vision of the always-connected, more autonomous vehicle of the future by pioneering C-V2X technologies, driving a rich roadmap to 5G, and bringing new levels of on-device intelligence. We are actively driving the C-V2X work in 3GPP, which builds on our leadership in LTE Direct and LTE Broadcast to pioneer C-V2X technologies. Learn more about C-V2X here.

As a co-founder of the 5GAA Alliance, we are vey pleased about the role of the association in fostering collaboration between the automotive and communications industries. We look forward to more positive developments in this space and more collaboration between governments, as well as, telecommunication and automotive industries.


27 de sep. de 2016