WiMAX World: Navini mixes beamforming, MIMO

BOSTON--Navini isn’t taking sides in the smart antenna debate. While other vendors tout their Multiple Input/Multiple Output (MIMO) and beamforming antenna technologies, Navini is incorporating both technologies into its new Mobile WiMAX gear.

The small broadband wireless vendor on Monday unveiled its Smart WiMAX platform ahead of the WiMAX World conference here, saying it has taken the nest of both of both beamforming and MIMO and put them into the same box. Beamforming uses multiple antennas to send a focused beam to an end user, creating a high-capacity link that can be steered throughout the cell area. MIMO uses those multiple antennas to multiple parallel signals, each of which is received and interpreted separately on the CPE.

While both MIMO and beamforming have capacity advantages over standard single antenna systems being certified today, MIMO is often cited as the better technology for dense urban deployments where the signals bouncing off of nearby structure reinforce rather than degrade a connection. Beamforming, meanwhile, is optimal for more stationary or portable applications where the focused beam can be extended far beyond the radius of the typical MIMO base station. MIMO has been clear technology of choice for must vendors, almost every single one of which has included the technology in its WiMAX migration path. Beamforming, however, has its advocates also, most notably Alcatel, which is targeting fixed and nomadic deployments for Mobile WiMAX as well as true mobile networks.

Some vendors have also pointed out that the two technologies are not mutually exclusive. They can be deployed base station by base station as individual cell conditions vary or they can be deployed side by side on the same base station, allowing the network to switch between beamforming and MIMO as the user moves and stops in the network. CPE chip developer Beceem has said its is working on dual-mode MIMO/beamforming devices with its vendor partners.

Navini, however, doesn’t seem to be taking a dual-mode approach. Instead it appears to be applying beamforming techniques to the individual signals transmitted from the MIMO antenna array. The combination gives MIMO-based networks the range of a beamformed signal without sacrificing mobility, Navini vice president of product management Sai Subramanian said, and has a cumulative capacity advantage of as six times that of a standard MIMO system.

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