Got a D-Link DIR-850L to replace DIR-845L

David Yin

11 years ago

Got DIR-850L at London Drugs. It is only $10 more than the one I got, DIR-845L at Costco. I did not see the benefits of SmartBeam^TM Technology. So I spend $109 to get a new router with 802.11AC support. 802.11AC is a new standard. See new technologies data from Wiki.

Extended channel binding
- Mandatory 80 MHz channel bandwidth for STAs (vs. 40 MHz maximum in 802.11n), 160 MHz available optionally
More MIMOspatial streams
- Support for up to eight spatial streams (vs. four in 802.11n)
Multi-user MIMO(MU-MIMO)
- Multiple STAs, each with one or more antennas, transmit or receive independent data streams simultaneously
  - “Space Division Multiple Access” (SDMA): streams not separated by frequency, but instead resolved spatially, analogous to 11n-style MIMO
- Downlink MU-MIMO (one transmitting device, multiple receiving devices) included as an optional mode
Modulation
- 256-QAM, rate 3/4 and 5/6, added as optional modes (vs. 64-QAM, rate 5/6 maximum in 802.11n)
- Controversy has been raised that this modulation rate is not suitable for any architecture other than extremely small cells and would be completely useless to 3GPP
Other elements/features
- Beamforming with standardized sounding and feedback for compatibility between vendors (non-standard in 802.11n made it hard for beamforming to work effectively between different vendor products)
- MAC modifications (mostly to support above changes)
- Coexistence mechanisms for 20/40/80/160 MHz channels, 11ac and 11a/n devices