The importance of a scalable network for growing WISPs

Many successful wireless ISPs began due to a lack of rural Internet service, or insufficient service by existing providers. During their initial phase, the ISP is enthusiastic to set up their network and is motivated by short term goals. Typically dealing with budget constraints, a basic wireless access technology is usually chosen. Once the first few paying customers sign up, a natural desire to secure additional revenue growth kicks-in, meaning a wider network with more users – and possibly some lucrative enterprise customers.


The average entrepreneur may find himself in a position where he is unable to scale his WISP network to the level he envisioned due to his network’s inability to increase capacity or add more users. This is the stage when WISPs begin to look for a viable solution to scale up their wireless network and increase their footprint and revenue, while maintaining Total Cost of Ownership (TCO) with marginal changes.


There are four main attributes that affect wireless network scalability:


Capacity Scalability


A single wireless Access Point (AP) on an isolated tower might deliver the network capacity defined according to data sheet specifications. However, in many Point-to-MultiPoint solutions, deploying an additional AP on a tower causes mutual interference with the adjacent AP, resulting in capacity deterioration in both the uplink and downlink direction.


This phenomena gets worse when more APs are deployed on the same tower, or on neighbouring towers: the more APs in a network, the less capacity is generated per AP.  Increasing the space between the APs on a tower or expanding the frequency guard band between them slightly improves capacity but wastes valuable tower space, as well as spectrum for the guard band.


The only way to avoid mutual interference is through TDD frame synchronization of all APs installed, via GPS so that all APs in the network transmit and receive at the same time to remove self-interference.


User Scalability


As the business grows, more residential users are typically added to a given sector. In many wireless access systems, the total capacity delivered from an AP tends to decline when more users are added to it.


An additional undesired phenomena is latency growth, which is common in Wi-Fi based networks, as the Wi-Fi air protocol lacks a traffic manager at the AP level. Latency growth is also common in many other proprietary systems due to the AP’s weak processing power and air interface protocol inefficiencies. A data sheet may specify 100+ users per AP, but what capacity is then achieved in a real-time deployment?


It’s best to evaluate the AP’s capacity with multiple active subscriber units, rather than just one or two.


Service Scalability

Most WISPs initially address the connectivity needs of households looking for basic internet access. The ARPU in this market is usually low and requires a significant helpdesk operation. Growing WISPs may want to scale the market segments they address but also target lucrative segments such as SMEs or enterprises demanding a Committed Information Rate (CIR) to assure their SLA.


WISPs should check that SLA services can be supported by the AP/base stations they plan to deploy.


Geographic Scalability


Successful WISPs consider growing their business into new areas or markets. A scalable PtMP solution should enable the replication and easy adaptation of a similar operation / solution type to different terrains and spectrum environments.


However, a suitable PtMP solution for rural deployments with little or no radio interference (when using 5GHz) may not deliver reliable connectivity in a suburban, congested spectrum. In addition, a PtMP solution that works well over short distances in local neighborhoods using line of sight, might not be suitable for nLOS scenarios in wider suburban areas or long distance, rural areas.


RADWIN JET PtMP – powered by its Bi-BeamTM beamforming antenna, is a highly scalable, carrier-grade solution. The base station is equipped with a built-in GPS receiver and embedded antenna to enable TDD synchronization. Its powerful processing power (500Kpps) together with unique Dynamic Bandwidth Allocation (DBA) and field proven air interface, enables 64 subscribers to connect to the internet with no capacity degradation whatsoever!


RADWIN JET delivers the highest industry capacity for a greater range, and radio interference immunity that is second-to-none. JET also employs an unmatched level of frequency re-use and the most advanced modulation scheme to gain more capacity from available spectrum.


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