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Technology Comparison - StreamStar4 vs. Long term Evolution (3GPP LTE)

 

Quick Comparison
 
LTE
StreamStar 4
Advanced Antenna Systems
2x, 4x MIMO
8x Phased Array (Beamforming)
Beamforming Gain
3 to 6 dB MIMO diversity gain
18 dB Downlink, 9 dB Uplink
Spatial Nulling Technology
NONE
YES
Air Interface Technology
OFDMA
Hybrid SCDMA+OFDMA
Native Voice Services
VoIP or VoLTE
YES
N=1 Capability
NONE
YES (Due to Spreading Gain)
Net Spectral Efficiency
1 b/s/Hz
2.8 b/s/Hz
Complicated Core Systems
YES (SGW ,PGW, MME, PCRF, etc)
NO

 

LTE vs. StreamStar4 on Range and Efficiency



LTE

LTE has some design inefficiencies that limit its coverage and capacity. With LTE's limited range, 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:
    The LTE Air Interface design is essentially an evolution of 802.11 Wi-Fi and 802.16 WiMAX standards, which are traditionally single antenna systems.  Due to single antennas the link budget is low and affects range, because indoor penetration incurs tremendous RF losses. At the same time, capacity is affected by the losses as well – with low SNR, LTE BTS and terminals are forced to use low modulation and strong error correction, severely reducing throughput.

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



  2. Plain OFDMA:
    LTE is still based on the OFDMA access scheme, just like WiMAX. Pure OFDMA has well-known, serious issues with frequency selective multipath - typical in a mobile and NLoS environments – 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 LTE systems, such as:

    - 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.


  3. Optimal Resource Granularity:
    StreamStar4 can assign user resources much more efficiently than LTE and can assign resources in much more efficient chunks, as small as 24 kbps per resource.

 

Summary

Lack of smart antenna systems in LTE means that intercell and inter-user 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 LTE 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 LTE 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.