The Long Term Evolution (LTE) standard defined by 3GPP is a
highly flexible radio interface that aims at bridging the gap
between 3G and 4G standards. LTE Release 8 specification was
completed in 2009 and triggered LTE service deployment by leading
mobile network operators. It has set various target requirements
to achieve higher system performance than HSPA in 3GPP Release 6.
It has improved system capacity, cell edge user throughput and
lower C/U plane latency, supported by introduction of new radio
interface technologies, such as OFDM, frequency domain scheduling
and MIMO. In the following year, LTE Release 9 has also been
completed to extend various functionalities in LTE Rel.8. The
area of enhancement includes closed subscriber group (CSG),
self-organizing network (SON), and new functionalities such as
location information service and MBMS (Multimedia Broadcast and
To keep up with the today's rapidly growing traffic,
especially by the wide spread of smart phone devices, it became
necessary to achieve much higher level of system performance,
while keeping the backward compatibility. Accordingly, the radio
access interface specifications for LTE-Advanced has been
developed in 2011. LTE-Advanced (LTE Rel.10 and beyond) sets a
major important milestone in standardization where meets and
exceeds requirements set by IMT-Advanced for 4G (International
Mobile Telecommunications). The new requirements include spectral
efficiency, higher bandwidth, and lower latency. To meet these
competitive requirements, a series of new technologies have been
introduced into LTE-Advanced, such as Carrier Aggregation,
Enhanced MIMO, and CoMP (Coordinated multi-point
transmission/reception). LTE-Advanced will enable higher than
1Gbps downlink bandwidth in addition to the existing LTE service
and open a new era of true wireless broadband services in the
near future. LTE-Advanced services will become available from
leading mobile network operators around 2014. Additional features
include non-contiguous spectra usage to further enhance the
current LTE services.
SAI Technology has been heavily engaged in LTE product
development from the early stages of LTE standards. SAI has
demonstrated complete end to end system solutions for eNodeB and
UE for LTE-Release 8 and 9. SAI is developing LTE advancements to
fulfill new and future generations of LTE products. SAI is
committed to delivery of LTE Advanced (Release 10 and beyond)
products by March 2012.
802.11 AC / AD / WiGiga
In 2009, 802.11n was ratified. It provides for up to 4x4
MIMO (Single user) along with wider bandwidths and a number of
MAC layer improvements leading to a peak theoretical throughput
in the order of 600 Mbps. Since the ratification of 802.11n, a
new task group (TGac) has begun working on the next standard for
even higher throughput within <6GHz spectrum. A closely
coupled task group (TGad) is looking at very high throughput for
spectrum >6Ghz (such as the 60 Ghz ISM band).
The IEEE 802.11ac Task Group (TG) has beendeveloping
amendment to IEEE 802.11 having PHY (Physical layer) as well as
MAC (Medium Access Control sub layer) enhancements. These
are the following goals for designing the IEEE 802.11ac
• Backward compatibility with IEEE 802.11a and IEEE
802.11n operated in 5GHz.
• Single STA throughput: 802.11ac STA shall be capable
of getting throughput up to 500Mbps.
• Multi-STA throughput: The aggregate throughput when
802.11ac system has multiple STAs connected should be greater
than or equal to 1Gbps.
New features in this standard are the bandwidths of 80 MHz
and 160 MHz (11n offered only 40 MHz), 256QAM, up to eight
antennas and multi-user MIMO.Gross data rates of 293 Mbit/s are
possible with only 80 MHz bandwidth, one antenna and 64QAM 5/6;
all 802.11ac devices must support this mode. Optional modes using
256QAM and eight antennas under optimal conditions permit gross
data rates of 3.5 Gbit/s. 802.11ac is designed only for
license-free 5 GHz bands and will no longer include the 2.4 GHz
industrial scientific medical (ISM) band previously used
primarily for WLANs.
For details on the exact extensions in the PHY layer, see
our whitepaper on 802.11ac PHY extensions.
SAI is developing 802.11ac PHY and MAC layer stacks, as
well as system solutions with particular emphasis on MU-MIMO high
performance implementation. This work is in collaboration with
leading silicon and SoC vendors for 802.11ac.
Concurrent with the802.11ac developments, a number of
industry groups are looking at the ISM band at 60 Ghz (typically
57-66 Ghz) as the next frontier for WLANs. Clearly, such a high
center frequency (mm wave) comes with a number of challenges
Limited range, due to the proximity of the oxygen
Implementation cost and high power consumption
MIMO techniques are helping overcome at least some of the
range issue, and a 32x32 antenna array can be easily implemented
on a CMOS process. Thus, as these hurdles are overcome the 60
Ghzband promises even higher data rates – up to 7 Gbps.
The IEEE 802.11ad standard adds a mm wave operating mode to
the 802.11n with a mmSTA being a station that is capable of mm
wave operations. Although the base protocol is an extension of
802.11n and 802.11ac, a number of mmWave mode specific packets
and formats have been defined in this standard(for e.g., mmWave
CTS). In addition, upto 5 bits are reserved for defining the
number of beams, thus permitting as many as 32 beams.
Due to the strong dependence on beamforming, considerable
effort is going into refining the beam forming procedures and
transactions within the 802.11ad standard. Similarly the large
number of receive and transmit chains required for such a system
are pushing the standards committee to refine the power
management techniques used in 802.11n/ac. MIMO for reducing power
consumption and turning off some of these chains when not
required without affecting network latency and performance.
This standard is in draft and still being developed,
although initial silicon is available from a select set of
Besides the 802.11ad standard, a few other standards are
being pursued for the 60 Ghz ISM band.
SAI is working with leading 60 GHz chip vendors for
802.11ad implementation on CMOS platforms. This work clearly
leverages SAI’s work on 802.11ac with a focus on high
performance and low power solutions.
The WiGig specification was contributed to the IEEE
802.11ad standardization process, and was confirmed in May 2010
as the basis for the 802.11ad draft standard.
In parallel with the 802.11 stream of standards, there has
been a steady march of Wireless personal area networks towards
the 60 Ghz ISM band as well. In particular the requirements of
being able to develop a wireless video area network for full HD
resolution leads towards similarly high data rate requirements.
The latest Wireless HD 1.1 standard aims for
Stream uncompressed audio and video up to Quad Full HD
48 bit color and 240 Hz refresh rates
Support for 3D video formats
Efficient data networking using IP
Flexible wireless connectivity using USB bridging
Simple, fast file transfer with OBEX.
Low rate PHY (2.5-40 Mb/s) for omni-directional control
Medium-rate PHY (0.5-2 Gb/s) for low power, mobile
applications and lowcomplexityuniversal bi-directional data
High-rate PHY (1-7 Gb/s) for high quality, full
Improved coverage and higher data rates (in excess of 28
Gb/s) through the use of
The spatial multiplexing high rate PHY (SM-HRP) option
Video coding to improve link robustness
HDCP 2.0 in addition to DTCP content protection support
SAI has completed significant work in video streaming on
existing protocols – WiMax, LTE as well as 802.11 in their
various forms (802.16e, 802.16d, 3G,LTE Rel 9 as well as
802.11g/n/ac). SAI is extending such video streaming work into
the Wireless High Definition technologies and markets for high
performance full resolution video.
This paper addresses the performance targets and the
technology components being studied by 3GPP for LTE Advanced. The
high level targets of LTE-Advanced are to meet or exceed the
IMT-Advanced requirements set by ITU-R. A short history of the
LTE standard is offered, along with a discussion of its standards
and performance. The technology components considered for
LTE-Advanced include extended spectrum flexibility to support up
to 100MHz bandwidth, enhanced multi-antenna solutions with up to
eight layer transmission in the downlink and up to four layer
transmission in the uplink, coordinated multi-point
transmission/reception, the use of advanced relaying and
heterogeneous network deployments.
Download LTE-Advanced White Paper PDF
Joint ITU-GISFI Workshop on
“Bridging the Standardization Gap: Workshop on
Sustainable Rural Communications”
(Bangalore, India, 17-18 December 2012)
LTE Advanced eNB Small Cell System
Design Challenges Network Topologies and Applications
By: Dr Venkat Rayapati,
Download LTE-Advanced Small Cell Systems Presentation PDF
Scale Solutions Across Mobile Networks
Sponsored by Avago Technologies
June - 2014
By: Dr Venkat Rayapati,
President & CEO of SAI Technology Inc.
Director of Technology,
Strategic Planning & Solution
Architecture, Network Solutions
Group, Avago Technologies
Download LTE-Advanced Small Cell Systems Presentation PDF
Video: SAI Technology presents LTE Mobile Software Defined
Networks and Applications
Video: SAI Techonology's CEO Dr. Venkat Rayapati presenting
material at Mobile World Congress 2014, Barcelona, Spain.
SAI worked with LSI to showcase their AXXIA 5500 processor
and demonstrate an architecture that will provide an optimized
LTE and Wi-Fi solution for enterprise networks.
Video: Multi-threaded LTE UE Baseband Solution from MIPS
and SAI Technologies.
Presentation Material based on a collaboration demo
presented at Mobile World Congress 2013 in Barcelona, Spain.
This video shows SAI Technology's CEO Dr. Venkat Rayapati
demonstrating LTE in the lab located at SAI Technology, Santa
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