When the transmit power output is reduced for one basestation, the power output for a neighboring cell might be increased slightly to maintain coverage yet reduce the typical amount of power that the two basestations would consume under normal circumstances. Reducing basestation power consumption takes on even greater importance as more and more basestations, including the new form-factor femtocell and picocell basestations, are deployed.

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Signal interference is another metric that a SON can automatically mitigate and thereby optimize the operation of the network. Signals coming from other cells in the neighborhood can cause interference. A SON can employ frequency management, beam forming, transmit-power reductions, and other techniques to reduce signal interference.

As 4G infrastructure equipment is deployed, interference will become even more critical. To increase capacity, coverage, and network bandwidth, more basestations will be installed. Some, like femtocells, will be nested inside of larger cells. A femtocell’s signaling must be closely controlled so it does not interfere with the operations of the macrocell within which it is located.

A basestation’s handling of RACH offers another optimization metric. Automatically setting up a SON basestation’s RACH configuration parameters such as the number of preambles on a packet and ramp-up power can reduce synchronization times, call setup times, and handover delays while improving other aspects of RACH performance.

The network’s coverage and capacity also can be optimized when SON basestations can dynamically alter parameters such as antenna tilt and reference power offsets to compensate for lapses in coverage and ensure adequate capacity where it’s needed. Mobility features like handoffs from one cell to the next can be optimized in a SON when basestations can balance load traffic among contiguous cells. SON basestations can monitor parameters like the elapsed time needed for handoffs, radio link failures, and access failures to maximize the number of handoffs that can be processed in any period.

Many other operational metrics can be optimized. Part of the beauty of 4G SON technology will be its adaptability to different service providers’ objectives as well as its ability to quickly respond to rapidly changing dynamic conditions in the network.

Delivering The 4G Promise

As wireless networks migrate toward 4G technology, the industry will be challenged to reduce operating expenses. The added complexity of 4G, if managed manually, will tend to drive operating expenses upward. Also, other variable costs like energy consumption have grown considerably in recent years. Automation, through 4G SON technology, is imperative if 4G networks are to reach their full potential and if the industry is to continue to provide service to a wide segment of the global economy.