All Beamforming Solutions Are Not Equal White Paper

Executive Summary This white paper compares and contrasts the two major implementations of beamforming found in the market today: ● Switched array beamforming ● Digital signal processing (DSP)-based beamforming This paper suggests that both methods do offer some performance gain but that DSP-based beamforming (such as used in ClientLink 2.0) is superior (especially when supporting a network with many clients) and therefore preferred for the following reasons: ● DSP-based techniques are used in 11n chipsets to improve uplink performance. These same DSP techniques can also be used to improve downlink performance. Switched arrays only improve downlink. ● DSP-based beamforming using multiple transmitters for downlink performance improvement is aided by using information acquired from multiple receivers during uplink performance improvement. A switched array cannot easily exploit information acquired in the uplink. ● DSP-based techniques can respond more rapidly to fluctuating RF conditions and therefore can support more clients. ● DSP-based techniques are better suited to orthogonal frequency-division multiplexing (OFDM)/(MIMO) multiple-input and multiple-output because the transmission of each subcarrier and each RF chain can be fine tuned for frequency selective fading (as typical in the wireless channel). Switched arrays do not have the ability to optimize per OFDM subcarrier or RF chain. ● DSP-based techniques are measurably better and validate theoretical/simulated analyses.