IEEE 802.11n interoperability testing that determines not just if systems interoperate but also their relative performance in communicating with other 802.11n systems based on different chipsets indicates that Metalink's WLANPlus chipsets lead the field.
Testing concluded in January by octoScope, an independent test laboratory, also simulated real-life conditionsthe walls of the testbed (a residential dwelling) are
constructed of stone, concrete and iron rods and the ceiling is made of concrete.
Metalink was the sole sponsor of the test, which included chipsets from Atheros, Broadcom, Marvel and Ralin as well as Metalink's WLANPlus.
octoScope has performed 802.11n testing in the past. In August, 2007, it provided WirelessNetDesignline results of system-level testing. More information is available at Testing 802.11n systems - Part 2: MIMO configuration analysis.
It is generally accepted that communicating pair of systems (access point and client) will deliver the highest data throughput performance when both systems are based on chip sets from the same vendor. Vendors often design in features that boost performance between systems using their chipsets.
The most surprising result of the octoScope tests is that when a competing chipset is paired with the WLANPlus chipset, throughput can actually be greater than the pairing of two chipsets from the same company.
The comparisons are most striking in the 5 GHz tests, most likely because the majority of vendors have devoted most of their attention to their 2.4 GHz designs. Figure 1 shows these comparisons. Metalink, on the other hand, has given its 5 GHz designs a higher priority because it has targeted wireless multimedia transport as a primary market.
Click here for Figure 1.
Figure 1: Results for various chipset pairings and distances for 5 GHz designs..
Although Metalink's advantage was not as striking in the 2.4 GHz tests, the WLANPlus chipset maintained its performance edge in most pairings. See Figure 2 below.
Click here for Figure 2.
Figure 2: Results for various chipset pairings and distances for 2.4 GHz designs..
Fanny Mlinarsky, octoScope's CEO, said: "Independent performance testing to date has used client-AP (Access Point) pairs based on chipsets from the same vendor. The complexity of the 802.11n specification, together with the many optional features in the emerging standard, may lead to unpredictable throughput between different chipset implementations. Therefore, we felt it was critical to measure cross-vendor interoperability performance of client-AP pairs based on chipsets from various vendors."
In an attempt to summarize the results of all of its testing, octoScope created an Interoperability Figure of Merit (IFM) that it considers to be directly relevant to data throughput between chipsets between different vendors.
IFM for an access point (AP) is the percentage of throughput for the AP-client pairs involving that AP with respect to total throughput for the test matrix. Similarly, IFM for a client is the percentage of throughput transported by the AP-client pairs involving that client with respect to total throughput in the test matrix.
Not surprisingly considering the previous results, Metalink had the highest AP and client IFM scores in both the 5 GHz and the 2.4 GHz. See Figure 3.
Click here for Figure 3.
Figure 3: Interoperbility Figure of Merit scores.
The complete test results, including a description of how the matrix of systems was set up is available at
More information is available at octoScope.
Barry Volinskey, Metalink's chief marketing officer, credited the favorable results to the decision to implement some optional parts of the 802.11n standard. WLANPlus has a "smarter" rate adaptation mechanism that minimizes packet error rate, he said, and its utilization of a maximum likelihood decoder alone accounts for a 3 to 5 dB improvement in sensitivity.
Volinsky said that tests showed that wireless connectivity and full home coverage cannot be achieved without having Metalink's chipset at least on one side of the network. WLANPlus demonstrated its unique capabilities as the only chipset enabling robust and reliable transmission of HD video at the 5GHz band, even to the farthest locations in the house.