WiMAX Buzz - The "Joke" of the Month

Australian WiMAX pioneer, Garth Freeman CEO of Australia’s Buzz Broadband, trashes WiMAX as “a miserable failure” and closed the WiMAX network.

Sounds prettty dramatic coming from a former true WiMAX Evangelist and believer in WiMAX wonders?

What happened to (past) Buzz claims that “The upgraded network will deliver high-speed, “ADSL-like” broadband and VoIP connectivity at distances exceeding 30 kilometers from the base station sites.”?

Is Buzz a naive "headless kankaroo" believing in supplier buzz of 30km cell ranges and 50+ Mbps at cell edge? (all sounds wonderfully similar to past, present and future promises of UMTS, HSPA-14Mbps and NGMN/LTE); Did Buzz make the effort to estimate the real system performance based upon link budget? Buzz might not have spend much money on engineering skills and more on market buzz? ..... Question Questions and Questions......

What went wrong with the Buzz?

Buzz Broadband (Australia) operates (actually operated) WiMAX at 3.4 GHz (based on 802.16e-2005) operating Wireless internet and VoIP. Having a little more than 22 base stations and using Airspan WiMAX system supporting roughly 150,000 customers/house-holds. In the service area Buzz is the only alternative to Telstra.

These claim is rather silly when inspecting the link budget which would make such ranges possible.

Using COST321 Walfish-Ikegami Model (Erceg path loss model gives pretty much similar results) targeting for 30 km cell range at 3.4 GHz being very (almost criminaly so) optimistic and assuming that Uplink and Downlink has the same performance;

With a Base Station (BS) Tx Power 100Watt (i.e., 50 dBm), MiMo 4x4 adaptive antenna system with 8 dBi per segment (too high! and @ minimum loss), Rx input sensitivity of -81 dBm (reasonable!), fade margin of 10 dB (reasonable but low), BS Antenna height 100 m (rather heigh) one would get in a Sub-urban environment a Downlink cell range of ca. 35 km and Uplink cell range of ca 20 km. While Downlink parameters theoretically could be met the Uplink assumptions to balance the link-budgets would be laughable. To be fair to the Buzz if the intention is to only support voice (over IP) the cell ranges do become less challenged.

Ignoring the buzz, inspecting real link budget data shows that even for voice the range would be maximum 0.7 to 1.0 km uplink limited, alas downlink the cell range can be extended to ca. 2 km (using latest antenna technology; i.e., MiMO 4x4 and adaptive antenna technology such as beam forming and limited mobility requirements).

One might argue that for covering Australia, the choice of 3.4GHz does not appear to be the best one. Moving to a lower frequency such as 2.4 GHz would improve the cell ranges with about 50% (i.e., from 0.7 km to 1.0 km).

Returning to the disappointed WiMAX buzz evangelist Mr. Freeman - What is really surprising is that he is surprised! - even more fun (or sad?) to see that religion has shifted to believing in 64QAM and wireless DOCSIS :-)

There are a lot of wonderfull books that cuts through the Buzz out there - even readable to non-technical CEOs; Mr. Freeman! do take a look at for example R. Olexa's book "Implementing 802.11, 802.16 and 802.20 Wireless Networks - Planning, Troubleshooting and Operations" or F. Ohrtman's "WiMAX Handbook - Building Wireless Networks" or hire some engineers with practical RF and real network deployment experience.