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Technology Comparison - StreamStar4 vs. WiMax 802.16e

 

Quick Comparison
 
WiMAX 16e / LTE
Alloyant StreamStar 4
Advanced Antenna Systems
AAS, MIMO
8x Phased Array (Beamforming)
Spatial Nulling Technology
NONE
YES
Air Interface Technology
OFDMA
Hybrid SCDMA+OFDMA
Native Voice Services
NONE (uses VoIP)
YES
N=1 Radio Planning Capability
NO (Impossible with plain OFDMA)
YES
Net Spectral Efficiency
1 b/s/Hz
2.8 b/s/Hz
Complicated Core Systems
YES (ASN-GW, Mobile-IP, etc)
NO

 


WiMAX vs. StreamStar4 on Range and Efficiency


WiMAX

WiMAX is a short range system, especially when required to achieve indoor penetration and mobility. Carriers will need to deploy a large amount of cell sites just to achieve coverage. Those who do not have infrastructure in place will need to build it from scratch, and cell sites are a huge capital and operational expense. Here are some of the deficiencies:

  1. Single Antenna Systems:
    802.16 WiMAX design is essentially an evolution of 802.11 WLAN standards, which are single antenna systems.  Due to single antennas, the link budget is low, affecting range – indoor penetration incurs tremendous RF losses. At the same time, capacity is affected by the losses as well – with low SNR, WiMAX BTS and terminals are forced to use lowest modulation and strong error correction, severely reducing throughput.

    In some WiMax systems, implementations of MIMO are used. However MIMO requires large amounts of spectrum; when spectrum is limited (as it usually is in licensed frequencies) MIMO has to be switched off. MIMO is much less effective than true beamforming in increasing system gain. Some WiMAX vendors claim that MIMO is beamforming. MIMO is a multiple antenna technique, but MIMO is not a true beamforming algorithm.

    MIMO is easy to design and cheap, thanks to its popularity in Wi-Fi (802.11n MIMO is used in home-use cheap WiFi access points and routers) but ineffective in large-scale deployments.


  2. Plain OFDMA:
    WiMAX 802.16e is based on the OFDMA access scheme. Pure OFDMA has serious issues with frequency selective multipath - typical in a mobile environment – and severe fading occurs. Symbols on the faded frequency bins cannot be detected and strong coding has to be used to recover. This significantly reduces throughput and efficiency, especially when dealing with narrowband components such as voice.

 

StreamStar4

  1. 8-Element Smart Antenna System:
    StreamStar4 broadband wireless systems use an 8-element Smart Antenna System with Digital Beamforming, that provides significant advantages over WiMAX systems:

    - Longer range:
    Smart antenna employs adaptive beamforming on both downlink and uplink, adding as much as 18 dB gain to the link budget, dramatically increasing range and indoor penetration.

    - Higher throughput:
    Extra beamforming gain allows the system to run higher modulation levels such as 16 and 64 QAM, both on uplink and downlink, increasing throughput.

    - Higher system efficiency:
    Smart antenna enables interference nulling and Dynamic Channel Allocation, which highly reduces co-channel interference (even when running N=1 reuse). This allows tight deployment of multiple base stations without fear of intercell interference.

    Beamforming is much more complex to achieve than simple systems like MIMO, but well worth the effort.

  2. Hybrid Air Interface:
    StreamStar4 employs hybrid SCDMA+ OFDMA technology, which is an optimal blend of CDMA and OFDMA. In the StreamStar4 Hybrid Air Interface, each symbol is spread across multiple frequency bins with certain separations. Fading of a few frequency bins does not seriously impact final detection of one symbol resulting in a highly reliable and efficient physical layer.



Summary

Lack of smart antenna systems in WiMAX systems means that intercell and interuser interference levels will be much higher, range and modulation efficiency will be lower, sacrificing performance and range. Based on pure OFDMA, inter-cell interference protection is not present in WiMax systems and network efficiency is severely reduced in dense deployments.

Thanks to CDMA spreading, smart antenna technology, and Dynamic Channel Allocation, StreamStar4 systems will be much more efficient than WiMAX especially in dense deployment scenarios. The abundant link budget will assure that StreamStar4 always performs at high modulation levels, maximizing terminal and BTS throughput.

With high system gain offered by beamforming, our base stations provide much longer range and coverage. This is a significant cost advantage to carriers, who need to deploy much less cell sites to cover targeted areas.

 

WiMAX vs. StreamStar4 on Voice and SMS capability


WiMAX

Some WiMAX CPE devices do include voice ports that are standard VoIP SIP phones using the G.729 codec. SIP is rather inefficient and with overheads and payloads will consume as much as 64 kbps of bandwidth for every voice call. Mobile voice and SMS are not possible at all. In addition, WiMax power management is primitive and mobile terminal battery life is severely reduced - the reason why there are no WiMax mobile handsets on the market.

 

StreamStar4

Since airlink and backhaul are the most valuable resource, StreamStar4 uses a proprietary, optimized protocol over the airlink and over the backhaul that consumes only 8 kbps per call. Each StreamStar4 BTS can support as much as 120 simultaneous mobile and fixed voice calls and 3000 voice subscribers, with seamless Make-Before-Break handoff between base stations.

StreamStar4 voice terminals are available as desktop modems with POTS voice (FXS line), as enterprise multi-line terminals, as fully mobile handsets, and as hybrid GSM/StreamStar4 mobile phones and PDAs. Mobile voice devices also support broadband data features, as well as SMS services.


Summary
Alloyant StreamStar4 offers a fully integrated system supporting broadband data and high-capacity voice, with portability, full mobility and a wide range of voice-capable user terminals.


WiMAX vs. StreamStar4 on Mobility


WiMAX

Originally, WiMAX by design was not made to support mobility (dynamic handoff). The later versions of 802.16e do have some support for mobility, however it is highly inefficient. Firstly, all mobility is handled by ASN gateway and mobile-IP routers, which are bulky and expensive devices. Secondly, IP mobility (handoff) is not transparent and requires client software on the user side. This severely limits the usefulness and usability of such mobility. Voice mobility in WiMax is not possible at all.

 

StreamStar4

Our system has mobility built-in to the base stations themselves. Smart L2 handoff ensures that sessions, IP addresses, VLAN tags - all are preserved even when terminals move from a base station to a base station or cell to cell. Voice mobility is native to the system and seamless with performance superior to CDMA and GSM handoff.

 

 

Summary

StreamStar4 offers a fully integrated system supporting broadband data and high-capacity voice, with portability and full mobility. Unlike WiMAX, there is no need for expensive and complicated ASN gateways, Mobile IP routers, or client software.