Overview on Mobile Broadband (MBB) Technologies

Overview on Mobile Broadband Technologies

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Enhanced Voice Service (EVS) Codec for LTE Rel-10

Its been a while we talked about codecs.

The traditional (narrowband) AMR (Adaptive Multi-Rate) codec operates on narrowband 200-3400 Hz signals at variable bit rates in the range of 4.75 to 12.2 kbps. It provides toll quality speech starting at 7.4 kbps, with near-toll quality and better robustness at lower rates and better reproduction of non-speech sounds at higher rates. The AMR-WB (Wideband) codec provides improved speech quality due to a wider speech bandwidth of 50–7000 Hz compared to narrowband speech coders which in general are optimized for POTS wireline quality of 300–3400 Hz. Couple of years back Orange was in news because they were the first to launch phones that support HD-Voice (AMR-WB).

Extended Adaptive Multi-Rate – Wideband (AMR-WB+) is an audio codec that extends AMR-WB. It adds support for stereo signals and higher sampling rates. Another main improvement is the use of transform coding (transform coded excitation - TCX) additionally to ACELP. This greatly improves the generic audio coding. Automatic switching between transform coding and ACELP provides both good speech and audio quality with moderate bit rates.

As AMR-WB operates at internal sampling rate 12.8 kHz, AMR-WB+ also supports various internal sampling frequencies ranges from 12.8 kHz to 38.4 kHz. AMR-WB uses 16 kHz sampling frequency with a resolution of 14 bits left justified in a 16-bit word. AMR-WB+ uses 16/24/32/48 kHz sampling frequencies with a resolution of 16 bits in a 16-bit word.

Introduction of LTE (Long Term Evolution) brings enhanced quality for 3GPP multimedia services. The high throughput and low latency of LTE enable higher quality media coding than what is possible in UMTS. LTE-specific codecs have not yet been defined but work on them is ongoing in 3GPP. The LTE codecs are expected to improve the basic signal quality, but also to offer new capabilities such as extended audio bandwidth, stereo and multi-channels for voice and higher temporal and spatial resolutions for video. Due to the wide range of functionalities in media coding, LTE gives more flexibility for service provision to cope with heterogeneous terminal capabilities and transmission over heterogeneous network conditions. By adjusting the bit-rate, the computational complexity, and the spatial and temporal resolution of audio and video, transport and rendering can be optimised throughout the media path hence guaranteeing the best possible quality of service.

A feasibility study on Enhanced Voice Service (EVS) for LTE has recently been finalised in 3GPP with the results given in Technical Report 22.813 ‘‘Study of Use Cases and Requirements for Enhanced Voice Codecs in the Evolved Packet System (EPS)”. EVS is intended to provide substantially enhanced voice quality for conversational use, i.e. telephony. Improved transmission efficiency and optimised behaviour in IP environments are further targets. EVS also has potential for quality enhancement for non-voice signals such as music. The EVS study, conducted jointly by 3GPP SA4 (Codec) and SA1 (Services) working groups, identifies recommendations for key characteristics of EVS (system and service requirements, and high level technical requirements on codecs).

The study further proposes the development and standardization of a new EVS codec for LTE to be started. The codec is targeted to be developed by March 2011, in time for 3GPP Release 10.

Fig. above illustrates the concept of EVS. The EVS codec will not replace the existing 3GPP narrowband and wideband codecs AMR and AMR-WB but will provide a complementing high quality codec via the introduction of higher audio bandwidths, in particular super wideband (SWB: 50–14,000 Hz). It will also support narrowband (NB: 200–3400 Hz) and wideband (WB: 50–7000 Hz) and may support fullband audio (FB: 20–20,000 Hz).

More details available in the following whitepapers by Nokia [PDF]:

• Media coding for the next generation mobile system LTE
• 3GPP Enhanced Voice Services (EVS) codec

HSPA+ Advanced - Enhancements beyond R10

Looks like Qualcomm is becoming my favourite company as the last few blog posts have been based on their documents and presentations. This one is a continuation of the last post on Multipoint HSPA.

HSPA+ Advanced - Enhancements beyond R10

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Related post: HSPA evolution – beyond 3GPP Release 10 - Ericsson

Multipoint HSDPA / HSPA

The following is from 3GPP TR 25.872 - Technical Specification Group Radio Access Network; HSDPA Multipoint Transmission:

HSPA based mobile internet offerings are becoming very popular and data usage is increasing rapidly. Consequently, HSPA has begun to be deployed on more than one transmit antenna or more than one carrier. As an example, the single cell downlink MIMO (MIMO-Physical layer) feature was introduced in Release 7. This feature allowed a NodeB to transmit two transport blocks to a single UE from the same cell on a pair of transmit antennas thus improving data rates at high geometries and providing a beamforming advantage to the UE in low geometry conditions. Subsequently, in Release-8 and Release-9, the dual cell HSDPA (DC-HSDPA) and dual band DC-HSDPA features were introduced. Both these features allow the NodeB to serve one or more users by simultaneous operation of HSDPA on two different carrier frequencies in two geographically overlapping cells, thus improving the user experience across the entire cell coverage area. In Release 10 these concepts were extended so that simultaneous transmissions to a single UE could occur from four cells (4C-HSDPA).

When a UE falls into the softer or soft handover coverage region of two cells on the same carrier frequency, it would be beneficial for the non-serving cell to be able to schedule packets to this UE and thereby improving this particular user’s experience, especially when the non-serving cell is partially loaded. MultiPoint HSDPA allows two cells to transmit packets to the same UE, providing improved user experience and system load balancing. MultiPoint HSDPA can operate on one or two frequencies.

Click to enlarge

There is also an interesting Qualcomm Whitepaper on related topic that is available to view and download here. The following is from that whitepaper:

The simplest form of Multipoint HSPA, Single Frequency Dual Cell HSPA (SFDC-HSPA), can be seen as an extension to the existing DC-HSPA feature. While DC-HSPA allows scheduling of two independent transport blocks to the mobile device (UE) from one sector on two frequency carriers, SFDC-HSPA allows scheduling of two independent transport blocks to the UE from two different sectors on the same carrier. In other words, it allows for a primary and a secondary serving cell to simultaneously send different data to the UE. Therefore, the major difference between SFDC-HSPA and DC-HSPA operation is that the secondary transport block is scheduled to the UE from a different sector on the same frequency as the primary transport block. The UE also needs to have receive diversity (type 3i) to suppress interference from the other cell as it will receive data on the same frequecny from multiple serving cells.Figure 1 llustrates the high-level concept of SFDC-HSPA.

In the case where the two sectors involved in Multipoint HSPA transmission belong to the same NodeB (Intra-NodeB mode), as illustrated in Figure 2, there is only one transmission queue maintained at the NodeB and the RNC. The queue management and RLC layer operation is essentially the same as for DC-HSPA.

In the case where the two sectors belong to different NodeBs (Inter-NodeB mode), as illustrated in Figure 2, there is a separate transmission queue at each NodeB. RLC layer enhancements are needed at the RNC along with enhanced flow control on the Iub interface between RNC and NodeB in order to support Multipoint HSPA operation across NodeBs. These enhancements are discussed in more detail in Section 4. In both modes, combined feedback information (CQI and HARQ-ACK/ NAK) needs to be sent on the uplink for both data streams received from the serving cells. On the uplink, the UE sends CQIs seen on all sectors using the legacy channel structure, with timing aligned to the primary serving cell.

When two carriers are available in the network, there is an additional degree of freedom in the frequency domain. Dual Frequency Dual Cell HSPA (DFDC-HSPA) allows exploiting both frequency and spatial domains by scheduling two independent transport blocks to the UE from two different sectors on two different frequency carriers. For a DC-HSPA capable UE, this is equivalent to having independent serving cells on the two frequency carriers. In Figure 3, UE1 is in DC-HSPA mode, whereas UE2 is in DFDC-HSPA mode.

Dual Frequency Four-Cell HSPA (DF4C-HSPA) can be seen as a natural extension of DFDC-HSPA, suitable for networks with UEs having four receiver chains. DF4C-HSPA allows use of the four receiver chains by scheduling four independent transport blocks to the UE from two different sectors on two different frequency carriers. DF4C-HSPA is illustrated in Figure 4.

Like SFDC-HSPA; DFDC-HSPA and DF4C-HSPA can also be intra-NodeB or inter-NodeB, resulting in an impact on transmission queue management, Iub flow control and the RLC layer.

Advantages of Multipoint transmission:

* Cell Edge Performance Improvement

* Load balancing across sectors and frequency carriers

* Leveraging RRU and distributed NodeB technology

Multipoint HSPA improves the performance of cell edge users and helps balance the load disparity across neighboring cells. It leverages advanced receiver technology already available in mobile devices compatible with Release 8 and beyond to achieve this. The system impact of Multipoint HSPA on the network side is primarily limited to software upgrades affecting the upper layers (RLC and RRC).

See also: FS_HSDPA_MP_TX: Study on HSDPA Multipoint Transmission

Device to Device communication (FlashLinQ?)

Recently I read on twitter that Qualcomm has asked 3GPP to do a study on device to device communication. Sometime back I blogged about FlashLinQ, Qualcomm's proprietary P2P communication technology. I am not sure if Qualcomm is pushing for this one or wants to have a study in general. If you know more details please add as comments.

Meanwhile, I found this video that explains what FlashLinQ does:

And there is also this presentation which is less technical and explains the information in the video.

FlashlinQ – Direct Device-to-Device Communication Technology

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More technically detailed presentation embedded in my earlier blog post here.

Ultra Self Organising Networks (UltraSON)

While watching the Femtocell Video, I was a bit curious on what exactly UltraSON does, so I decided trying to find more info. Surprisingly the information was hard to come by. I finally managed to find the Qualcomm site that has more details but surprisingly it wasnt east to find. From the website (link at bottom):

Qualcomm femtocell R&D program is focused on developing self organizing network features to address interference and mobility management for femtocell deployment in residential and enterprise environments. Interference and mobility management is a chief concern especially when operators are planning for high levels of perfromace from dense and an unplanned femtocell deployments. Qualcomm has developed UltraSON™, a comprehensive suite of interference and mobility management techniques for femtocell deployments in residential and enterprises.

The techniques that make UltraSON:

More details on UltraSON at : http://www.qualcomm.com/research/femtocells

Interesting promotional Femtocell video by Qualcomm

2020: Radio and Mobile Broadband (MBB) Beyond 4G

An interesting presentation and whitepaper from Nokia Siemens Networks embedded below:

Mobile Broadband Beyond 4G

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Nokia siemens networks beyond 4 g white paper online 20082011

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Related post: 2020: More than 50 Billion connected devices - Ericsson

Two interesting NGMN papers on Backhaul

There are some interesting blog posts on Broadband Traffic Managemenet on Backhaul. Here are few excerpts:

Traditional network management practice says that network element usage level should not exceed 70% of its capacity. If it does - it is time to do something - buy more or manage it better. So, according to a recent Credit Suisse report - it is time to do something for wireless networks, globally. For North America, where current utilization at peak time reaches 80% it is even urgent.

Phil Goldstein (pictured) reports to FierceWireless that - "Wireless networks in the United States are operating at 80 percent of total capacity, the highest of any region in the world, according to a report prepared by investment bank Credit Suisse. The firm argued that wireless carriers likely will need to increase their spending on infrastructure to meet users' growing demands for mobile data .. globally, average peak network utilization rates are at 65 percent, and that peak network utilization levels will reach 70 percent within the next year. .. 23 percent of base stations globally have capacity constraints, or utilization rates of more than 80 to 85 percent in busy hours, up from 20 percent last year .. In the United States, the percentage of base stations with capacity constraints is 38 percent, up from 26 percent in 2010"

And

The Yankee Group provides the following forecast for mobile backhaul:

Average macrocell backhaul requirements were 10 Mbps in 2008 (seven T1s, five E1s). In less than three years, they have more than tripled to 35 Mbps in 2011, and by 2015, Yankee Group predicts they will demand 100 Mbps.

There were 2.4 million macro cell site backhaul connections worldwide in 2010, growing to 3.3 million by [2015?]

Yankee's new research conclude:

"The market for wholesale backhaul services in North America will grow from $2.45 billion in 2010 to $3.9 billion in 2015, with the majority of this growth coming from Ethernet backhaul. Successful backhaul service providers will be those that can demonstrate price/performance and reliability, have software tools in place and can meet the specific needs of the mobile market.

And recently:

A Dell'Oro Group report forecasts that "Mobile Backhaul market revenues are expected to approach $9B by 2015. This updated report tracks two key market segments: Transport, which includes microwave and optical equipment, and Routers and Switches, which includes cell site devices, carrier Ethernet switches, and service provider edge routers .. routers and switches expected to constitute 30% of mobile backhaul market "

Shin Umeda, Vice President of Routers research at Dell’Oro Group said: “Our research has found that operators around the world are concerned with the rate of mobile traffic growth and are transitioning to Internet Protocol (IP) technologies to build a more efficient and scalable backhaul network. Our latest report forecasts the demand for IP-based routers and switches will continue to grow through 2015, almost doubling the market size of the Router and Switches segment in the five-year forecast period”

I have some basic posts on why Backhaul is important, here and here.

NGMN has timely released couple of whitepapers on the Backhaul.

The first one, 'Guidelines for LTE Backhaul Traffic Estimation' document describes how a model is developed to predict traffic levels in transport networks used to backhaul LTE eNodeBs. Backhaul traffic is made up of a number of different components of which user plane data is the largest, comprising around 80-90% of overall traffic, slightly less when IPsec encryption is added. These results reveal that the cell throughput characteristics for data carrying networks are quite different to those of voice carrying networks.

The purpose of second one, 'NGMN Whitepaper LTE Backhauling Deployment Scenarios' is to support operators in their migration from current architectures to new, packet-based backhaul networks. With the introduction of LTE operators need to look at how the backhauling network, the network domain that connects evolved NodeBs (eNBs) to MME and S/P-GW, is capable of adapting to the new requirements, namely the adoption of a packet infrastructure, without disrupting the existing services. This paper introduces some reference architectures, moving from a pure layer 2 topology to a full layer 3 one, discussing some elements to be considered in the design process of a network.

They are both long but interesting read if you like to learn more about Backhaul and the best way in future proofing the network deployments.

LTE Advanced HetNet Benefits!

Presentation from Qualcomm Webinar, LTE-Advanced Hetnet benefits.

LTE Advanced HetNet Benefits!

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Qualcomm is undisputed leader in the LTE chipsets and have been pushing hard for the next generation LTE-A chipsets. Here is a promotional LTE-Advanced Video on Youtube: