LAA is part of 3GPP Release 13, which was frozen in Mar. 2016.
Licensed Assisted Access (LAA) is introduced in 3GPP release 13 as part of LTE Advanced Pro. It uses carrier aggregation in the downlink to combine LTE in unlicensed spectrum (5 GHz) with LTE in the licensed band. This aggregation of spectrum provides for a fatter pipe with faster data rates and more responsive user experience. For example, a mobile operator using LAA can support Gigabit Class LTE with as little as 20 MHz of licensed spectrum. By maintaining a persistent anchor in the license spectrum that carries all of the control and signaling information, the user experience is both seamless and reliable.
In a joint effort, Qualcomm Technologies, Inc. and Deutsche Telekom conducted the world’s first over-the-air LAA trial during November 2015 in Nuremberg, Germany, which is a big milestone towards commercial deployment. A wide range of test cases were completed: indoor and outdoor, different combinations of LAA/LWA/Wi-Fi, single and multiple users – both stationary and mobile, handover between cells, and a range of radio conditions. The trial results clearly demonstrated:
Fair co-existence of LAA with Wi-Fi over all test cases
Coverage & capacity benefits of LAA over Wi-Fi1
Seamless mobility of both LAA and LWA
LAA provides the same powerful benefits as LTE-U from aggregating LTE in both licensed and unlicensed spectrum with the additional benefit that LAA meets global regulations. LTE-U was introduced to address time-to-market needs in specific regions such as USA, India and Korea.
LAA includes “Listen Before Talk” (LBT) suitable for global deployment, including EU and Japan. Both LAA and LTE-U ensures fair co-existence with Wi-Fi.
Fair Wi-Fi coexistence is a key principle in LAA. This is accomplished by dynamically selecting clear channels in 5 GHz to avoid Wi-Fi users. If there is no clear channel available, LAA will share a channel fairly with others. This is accomplished by a feature called Listen Before Talk (LBT). LBT will be used by all technologies in unlicensed spectrum to ensure fair coexistence globally.
LAA is part of 3GPP Release 13, which was frozen in Mar. 2016.
LBT is a standardized method that ensures fair spectrum sharing; applies to both LAA, eLAA, MulteFire, and Wi-Fi in the next release of ETSI EN 301 893.
For the end-users, LAA offers higher bandwidth through carrier aggregation, same excellent reliability as in licensed spectrum, and a seamless experience when moving in and out of small cell coverage, which together results in an overall better user experience.
For the mobile operator, LAA offers enhanced capacity and coverage over Wi-Fi, a common unified network that simplifies management, and future-proofing towards hyper-dense, self organizing networks, which means cost savings in terms of deployment and operation.
LAA will enjoy 3GPP's cadence of regular enhancements and the subsequent 3GPP release 14 will introduce enhanced LAA (eLAA). The LTE-U specification enables a migration to LAA, which is validated enabled by Qualcomm Technologies’ FSM SoC supporting a software upgrade path from LTE-U towards LAA.
Here are two important LAA features expected in eLAA and beyond:
Introducing the Qualcomm® Snapdragon™ X16 LTE modem — the world’s first announced LTE modem with support for Gigabit class LTE and LAA/LTE-U. By aggregating both licensed and unlicensed spectrum using LAA/LTE-U, mobile operators with as little as one block of 20 MHz licensed spectrum can deploy Gigabit Class LTE.
Qualcomm Snapdragon is a product of Qualcomm Technologies, Inc.
eLAA capacity and co-existence demo at MWC 2016
eLAA coverage demo at MWC 2016
Light Reading Interview: Evolving LAA and introducing MulteFire at MWC 2016
Progress on Licensed-Assisted Access (LAA) and Its Relationship to LTE-U and MulteFire
With the acceleration of the 5G New Radio (NR) standards, the interest in 5G shared spectrum grows. The good news is that 5G NR is designed to operate over a wide array of spectrum bands, from low bands below 1 GHz and mid bands from 1 GHz to 6 GHz, to high bands such as mmWave. In addition, 5G NR is also designed to operate across different spectrum types, from licensed spectrum to unlicensed and shared spectrum (Figure 1).
5G NR promises to support a wide variation of requirements from extreme bandwidth to use cases such as immersive virtual and augmented reality, connecting the massive Internet of Things and enable mission-critical services with sub-millisecond latency. So far, the main industry focus for 5G NR has been on licensed spectrum. It is important, however, to note that access to shared/unlicensed spectrum can extend 5G in multiple dimensions, including enhanced end-user data rates with opportunistic access to more spectrum, more efficient local and private network operation, and new deployment use cases for industrial applications. 5G NR is designed to natively support all spectrum types with the flexibility to take advantage of potentially new spectrum-sharing paradigms, thanks to the design of frame structure with forward compatibility. This creates opportunities for new innovation to take spectrum sharing to the next level in 5G.
For mobile operators, 5G spectrum sharing will enable operators to opportunistically aggregate more spectrum to dynamically support extreme bandwidths for fiber-like experiences. Additionally, 5G spectrum sharing can extend the benefits of 5G NR technologies and the ecosystem to entities that do not have access to licensed spectrum, such as cable operators, enterprises and IoT verticals (Figure 2).
Qualcomm Technologies is already pioneering spectrum-sharing technologies in LTE with concepts such as:
We are building and expanding on these concepts in 5G NR, and yet adding innovations around new spectrum-sharing paradigms. So what are these new innovations? As already mentioned, a main disadvantage of unlicensed/shared spectrum is the lack of QoS guarantee. Concepts such as QoS are nowadays taken for granted in licensed spectrum, but are more challenging when sharing spectrum. As such, some of the innovation is focused on making spectrum sharing operate robustly to approach the predictable performance of licensed spectrum while maintaining the flexibility.
Another area of innovation is to improve the overall spectrum utilization when sharing the spectrum among multiple deployments. This can be achieved by dynamic listen-before-talk at lower loads, since collisions are less likely and gains are seen from trunking efficiency over a fixed-resource partition when combining traffic in the same spectrum. At higher loads, however, achieving higher performance with dynamic sharing over a fixed-resource partition is more challenging due to more collisions. This is another area for new innovation that, with a clever coordinated sharing mechanism, one can achieve significant performance merit with dynamic spectrum sharing across loading conditions as illustrated by our early simulation results (Figure 3).
This week we announced a 5G NR spectrum-sharing prototype system (Figure 4). We will use this testbed to both drive and track 5G NR standardization in the area of spectrum sharing. Next year, the focus of the testbed will be on technology development, but we are already planning to follow up with field trials with industry leaders. This testbed adds to our existing 5G NR sub-6 GHz and millimeter wave prototype systems. We are excited to bring additional innovation to 5G in the area of spectrum sharing and we see a lot of potential for 5G to leverage all spectrum types in both licensed and unlicensed as well as new shared-spectrum paradigms. To learn more about 5G shared spectrum please visit our webpage.
LTE Advanced continues to evolve toward LTE Advanced Pro with the objective to connect new industries, enable new services and empower new user experiences, pushing the boundaries and capabilities of LTE toward 5G. Licensed Assisted Access (LAA) is a key LTE Advanced Pro feature that extends the benefits of LTE to unlicensed spectrum, not only to help satisfy the increasing demand for data, but also enabling more operators to offer Gigabit-class speeds to end-users through the aggregating of unlicensed spectrum with licensed—a glimpse of the 5G future.
A major LAA milestone was achieved when Deutsche Telekom and Qualcomm Technologies, Inc. conducted the world’s first LAA over-the-air trial November 2015 in Nuremberg Germany. The trial was completed on November 20th after a three-week period of extensive testing that spanned a wide range of network at indoor and outdoor topologies using multiple LAA small cells, Wi-Fi access points, LAA devices, Wi-Fi devices and LWA devices (LTE Wi-Fi Link Aggregation). Deutsche Telekom provided the licensed spectrum for the LTE anchor carrier, augmented with 5 GHz unlicensed spectrum in a test network deployed over Qualcomm’s Nuremberg campus.
The trial LAA test equipment was designed and deployed by Qualcomm Research, the R&D division of Qualcomm Technologies Inc. The LAA test equipment complies with current 3GPP Release 13 development and is particularly designed to meet global unlicensed band regulations, including “Listen-Before-Talk” features using extended Clear Channel Assessment procedures and channel occupancy limits required in regions such as Europe and Japan.
An extensive set of tests were performed, exemplified here with two examples, to demonstrate LAA’s extended coverage and increased network capacity compared to Wi-Fi 802.11ac, as well as seamless mobility with opportunistic aggregation of unlicensed spectrum during drive tests. The test conditions in the unlicensed spectrum were the same for both LAA and Wi-Fi, including antennas, transmit power, channel frequency, speed, 2x2 MIMO, etc.
The first example from the outdoor OTA trial that shows that LAA is an excellent neighbor to Wi-Fi; two out of the four outdoor Wi-Fi access points are replaced with LAA small cells to demonstrate the LAA impact on the other two Wi-Fi access points; as shown, all users are better off with LAA as a neighbor and the remaining Wi-Fi users experience a much higher throughput. In the complete set of test cases, the fair coexistence between LAA and Wi-Fi in unlicensed 5 GHz bands was demonstrated under different radio conditions and for a varied number of interfering nodes.
The second example shows the LTE and Wi-Fi coverage in unlicensed spectrum using a slow- moving van along a drive route through the Nuremberg campus. Not only does LAA reach farther to provide longer range in general, it also consistently provides higher user throughput speeds over a larger portion of the test route.
In addition to these examples a wide range of test cases were performed including: indoor and outdoor deployment scenarios, different combinations of LAA, LWA and Wi-Fi, single and multiple users, stationary and mobile users, handover between multiple small cells and a range of different radio conditions.
Following the success of the OTA LAA trial with Deutsche Telekom, the Qualcomm Research team plans to expand the OTA LAA network with new features and enhancements as LAA system design and standardization progress, and to demonstrate LAA enhancements at MWC 2016 such as link aggregation with unlicensed spectrum also in the uplink. For more details on LAA, see our website.