A couple of months ago we left pending the market study on Wimax market. The next phase of the study is the analysis of the different scenarios in what you usually make use this kind of equipment. We are going to see the features required by each of them and determine the equipment that in my opinion meets their needs the best.

In my opinion theere are the three scenarios where Wimax technology fits perfect: WISP, corporate networks and backbone for telecom providers.

Corporate networks

In this category we will consider private networks performed by both point to point and point to multipoint links. We aren't going to distinguish between public and private networks becasue most of their needs are common. In this scenario we can define three fundamental elements to take a decission in which is our perfect device: capacity, security and availability of links.

Because of the importance of these three elements I consider the RADWIN 2000, Alvarion BreezeUltra, Proxim QuickBridge and Cambium PTP as the best candidates for this scenario. All of them offer the features required for these scenarios, so choosing one or the other will depend largely on the rest of the project requirements (links symmetry, QoS, L3 capabilities, ...) that we will not look so in detail. What we can do is highlight those distinguishing features of such equipment to facilitate the choice of one or the other depending on the scenario.

• Cambium Networks PTP:   solutions with up to 300 Mb / s. Scalable capacity via software. Configurable Symmetry (1:3, 1:1, 3:1). Market leaders in sensitivity (-94 dBm) and spectral efficiency (Mb / Hz) . Possibility of use of synchronism solutions using PTP-Sync. Version with 1000Base-X available. Optimal planning software.
• RADWIN 2000 High capacity (200 Mb / s) configurable in symmetry. Possibility of synchronism by HSS solution. Same hardware for working at 5.4 and 5.8 GHz. Optimal planning software. Version with 1000Base-X available.
• Alvarion BreezeUltra: high-capacity solution (300 Mb / s) based on 802.11n. Same hardware for 5.4 and 5.8 GHz with the possibility of using the same solution as point to point or point to multipoint (Feature in roadmap).
• Proxim QuickBridge 8100: can work in router mode. Same hardware for 5.4 and 5.8 GHz up to 300 Mb / s with 40 MHz channels based on 802.11n.

Talking about PmP solutions there are more elements that can define the decision to take. If what is required is a solution with much capacity to share in a controlled number of dependencies, Radwin 5000 HPMP solution is the best choice. Otherwise the solutions of Cambium PMP430 , BreezeACCESS VL Alvarion or Proxim MP8100 also cover the needs of these projects. Besides the imminent appearance on the market of Cambium Networks PMP450 can make a good alternative to consider in this type of scenario. As we have done with the Point to Point solutions we will analyze the main strengths of each platform:

• Cambium Networks PMP430/450: solution with very good spectral efficiency and scaling facilities offered by software licenses. Canopy technology. Ability to work in router mode.GPS sync posibility.
• Radwin 5000 HPMP: high capacity (200 Mb / s). Performance optimized to work with controlled number of subscribers. SLA guaranteed by customer. Same hardware for 5.4 and 5.8 GHz. Possibility of using GPS synchronization.
• Alvarion BreezeACCESS VL: Scaled solution that allows software licenses for upgrading. Competitively priced for less than 8 subscribers and capacity up to 6 Mb / s.
• Proxim QuickBridge 8100: can work in router mode. Same hardware for 5.4 and 5.8 GHz up to 300 Mb / s with 40 MHz channels based on 802.11n.

WISP (Wireless Internet Service Provider)

Such projects can distinguish solutions depending on several parameters, but they all share a common factor, the cost of CPEs should be tight enough so that the ROI of the project is adequate. Once analyzed technical equipment available and making this first economical filter I think the devices that would adapt best to this scenario are: Cambium Networks PMP430 (450 is actually available) and Airmax Ubiquity. At this point it would be necessary to examine other factors that will lead us to make a decision:

• Interference management: If this is one of the determining factors when looking for a solution we need to look for equipments with internal mechanisms for managing transmissions and collisions in the physical medium and  allow to use synchronism techniques  to improve link performance. That is why I believe that the solution of Cambium Networks PMP430 is the best suited to it. If you remember the other day we talked about the shortcomings of 802.11-based equipment could present in this type of functionality.
• Future Growth: usually a WISP has the need to expand the capacity of a sector by adding additional base stations. In this case the use of synchronization mechanisms become crucial because to match two or more teams in the same location as offers a high level of instability and decline in system capacity. That is why the PMP430 solution  becomes the best choice in this regard.
• Number of subscribers per sector: In this element the solutions of Cambium and Ubiquity offer similar performance. Like any wireless technology make the number of subscribers growing affects the delay of our communications and that's a critical fact if we want to offer VoIP services. In this point Cambium solution offers more stability than Ubiquity.
• Cost: In this aspect Airmax Ubiquity has a really low cost, so that if that's the only factor that leads to the optimal solution, that's Ubiquity. It is a platform whose CPEs can be purchased for about 50 €.

It seems that the market puts the solution Cambium PMP430 one step ahead technologically talking from Ubiquity, which is already one step ahead at cost. To get an idea of prices that could manage to implement a WISP project with 3 base stations and 200 CPEs is € 12,000 with a Ubiquity solution and € 28,000 for Cambium one.

Backbone for carriers

The last scenario analyzed in this study is backbone solutions for operators. This scenario requires point to point links to interconnect several distribution nodes that transmit signals from operators BTS .

In this environment the main features required by our equipments are: ability to work in saturated spectrum environments spectrum, availability and possibility of TDM transmission. The latter condition severely limits the number of devices to watch at, as it is not usual to have equipment that directly provide an interface for interconnection of TDM traffic. In this case Radwin 2000 and Cambium PTP600 are perfect. They offer TDM interfaces, provide an  adequate capacity for normal requirements and the possibility of being synchronized via GPS.

I hope that after all this writing (if someone has got here is that he is really interested in the subject) any of you can understand why exist these differences in price between the different equipments and why is difficult for  engineers to answer that question about a vendor costing twice the one that the customers has seen in Media Markt.

I think or at least I hope that the goal of this post has been reached, I want to demonstrate that Wimax network design must never be based on the information provided in the datasheet of the vendor or what your your neighbor has told you. Instead of that you should talk to radio professionals who can treat this kind of projects as they need.