Why We Say
High Capacity
Multiple Input Multiple Output (MIMO)
In real-world environments, signals reflect from various objects to reach the receiving antenna, hence a signal follows different distances before being received. This phenomenon is called Multipath propagation and causes interference and fading in non-MIMO radios. On the receiver side, having multiple receivers increases the amount of received power and also reduces multipath problems by combining the received signals for each frequency component separately. Hence, MIMO significantly improves the overall gain.
Proxim’s MIMO Features
- Proxim’s backhaul products Tsunami® QB-8200 & MP-8200 Series products feature top of the range 3x3 MIMO capabilities with spatial multiplexing
- Proxim’s Access Points ORiNOCO® AP-8100 are 802.11n products featuring 3x3 MIMO with spatial multiplexing
- Significant hike in throughput and range with no increase in transmit power or channel bandwidth
- MIMO-OFDM combination radios solve interference, fading and multipath problems
- Higher spectral efficiency and robust signal quality results in significant increase in overall gain
- Incredible performance gains at lower costs
MIMO also uses Spatial multiplexing transmission technique to transmit independent and separately encoded data signals from each of the multiple transmit antennas while reusing or multiplexing in the space dimension. These independent data signals are called Spatial streams. The transmitting antenna uses multiple radio Tx chains and signal paths to simultaneously transmit different data streams, whereas the receiver combines the Rx signals resulting in higher throughput.
By increasing the number of receive and transmit antennas, the throughput of the channel increases linearly resulting in high spectral efficiency. MIMO technology has become one of the most important wireless techniques to be employed in recent years especially as the spectrum is becoming a more valuable commodity than ever for wireless communications. MIMO radio technology being integrated into many new technology standards like LTE, WiMax, Wi-Fi and many other wireless technologies to provide improved spectral efficiency along with increased link capacity and reliability.
Wi-Fi networks are often plagued with inadequate range and spotty coverage resulting in performance fluctuations. Stable bandwidth is vital for latency sensitive real time applications such as video streaming, online gaming, VoIP, web surfing, etc. Proxim’s top-of-the-line ORiNOCO® Wi-Fi Access Points AP-8100 feature the 802.11n Wi-Fi standard delivering up to 320Mbps real throughput with 3x3 MIMO and spatial multiplexing to offer next generation internet experience today. Only a couple of backhaul products feature 2x2 MIMO in the marketplace, Proxim’s Tsunami® QB-8200 and MP-8200 Series go a step further to use sophisticated 3x3 MIMO to increase signal robustness and range.
Wi-Fi networks are often plagued with inadequate range and spotty coverage resulting in performance fluctuations. Stable bandwidth is vital for latency sensitive real time applications such as video streaming, online gaming, VoIP, web surfing, etc. Proxim’s top-of-the-line ORiNOCO® Wi-Fi Access Points AP-8100 feature the 802.11n Wi-Fi standard delivering up to 320Mbps real throughput with 3x3 MIMO and spatial multiplexing to offer next generation internet experience today. Only a couple of backhaul products feature 2x2 MIMO in the marketplace, Proxim’s Tsunami® QB-8200 and MP-8200 Series go a step further to use sophisticated 3x3 MIMO to increase signal robustness and range.
Dynamic Data Rate Selection
Dynamic Data Rate Selection (DDRS) feature allows the BSU or SU (or end points in PtP Link) to monitor the remote average signal-to-noise ratio (SNR) and the number of retransmissions between the BSU and SU or vice versa. The BSU or SU adjusts the transmission data rate to an optimal value to provide the best possible throughput according to the current communication conditions and link quality. The BSU or SU runs the DDRS Algorithm separately based on their local DDRS Status configuration. When DDRS Status is enabled on the SU, it monitors the remote SNR and number of retransmissions for BSU and can adjust the transmission rate according to the link condition.
As shown above, DDRS ensures optimum throughput by adjusting the data rate of the connection depending not only on the distance between the Subscriber and the base unit but also on the interference between them.
What is the difference between data rate and throughput?
Data Rate refers to the theoretical speed of the link. It includes not just the data payload but entails the protocol overheads too. Protocol overheads typically involve the source and destination address and also many other information such as CRC for ensuring the communication is error free.
Throughput refers to the real world or the actual speed of the link. Throughput of a link includes only the data payload and refers to the amount of actual data you can transfer across the network in a given amount of time.
Throughput refers to the real world or the actual speed of the link. Throughput of a link includes only the data payload and refers to the amount of actual data you can transfer across the network in a given amount of time.
How do typical wireless connections suffer without DDRS?
Commonly known as free space path loss (FSPL), a wireless signal typically loses strength / attenuates as the coverage area of the network expands i.e. the distance propagated by the wireless signal .In addition to the FSPL, other factors such as reflection and absorption commonly prevalent in weather conditions like rain, snow etc severely affect the signal strength of a wireless link not to mention the interference caused by neighboring wifi radios and non-wifi devices. Consequently a reduction in signal strength causes data corruption as the stations are unable to “hear” each other. This further reduces the quality and the capacity of the link due to multiple retransmissions of management frames sent by the participating stations in a bid to maintain the fixed data rate.
How does DDRS enhance wireless communication?
Available only with Proxim’s proprietary router technology WORP Drive®, DDRS enables Proxim’s radios to dynamically adjust the data rate depending on the environment and the distance of the wireless link. This adjustment in the data rate ensures fewer retransmissions and increases the efficiency of the links by allowing more data packets to be exchanged instead of management frames.
IGMP Snooping
Proxim’s Tsunami® devices support Internet Group Management Protocol (IGMP) snooping feature. With IGMP Snooping enabled on the device, multicast traffic is only forwarded to ports that are members of the specific multicast group. By forwarding the traffic only to the destined ports, reduces unnecessary load on devices to process packets.
WORP Intra Cell Blocking
The WORP Intra Cell Blocking feature restricts traffic between SUs which are registered to the same BSU. A user can form groups of SUs at the BSU which define the filtering criteria. All data to/from SUs belonging to the same group are bridged. If an SU does not belong to any group, the BSU discards the data.
Advantages of isolating traffic among subscriber units are:
- To provide better security by isolating the traffic from one SU to another in a public space.
- To block unwanted traffic between SUs to prevent this traffic from using bandwidth.
Satellite Density
Satellite Density setting helps to achieve maximum bandwidth in a wireless network. It influences the receive sensitivity of the radio interface and improves operation in environments with high noise level.
A user can configure the Satellite Density to be Disable, Large, Medium, Small, Mini, or Micro. The Medium, Small, Mini, and Micro settings are appropriate for higher noise environments; whereas, Large is appropriate for a lower noise environment. Reducing the sensitivity of the device enables unwanted “noise” to be filtered out as it disappears under the threshold.
Roaming
When an SU is roaming between wireless network coverage areas, the SU terminates the session with the current BSU and registers with another BSU. The Fast Roaming feature continuously monitors the local SNR (Signal-to-Noise ratio) and Data rate on the SU for all the frames received from the connected BSU. As long as the local SNR and Data rate is greater than the set threshold values the SU does not scan for other BSUs. When the SNR and Data rate breach the lower threshold, the SU scans for a BSU with a better signal strength and when there are multiple BSU options, the SU connects to the BSU with the most robust signal.
Proxim’s Fast Roaming:
- Seamless connectivity within Proxim’s wireless network
- Hotspot islands merged into one virtual network
- Subscriber is always connected to the home network
- Handoff is established within 40ms
Auto Multi Frame Bursting
Multiframe Bursting
To achieve higher throughput, WORP protocol allows the transmitter or receiver to send multiple data frames in sequence without waiting for acknowledgment for every data frame and treats it as a single burst. During the burst transmission, the receiver is not allowed to interrupt the transmitter. After compilation of the burst, the receiver responds by sending the acknowledgement.
