"In South Korea, SK Telecom has cut its 4G pricing to remain competitive. Their 'LTE 62 Plan' for smartphones used to be priced US$55.04 for 3 GB of data, but the monthly download quota has now been increased to 5 GB. ABI Research has seen similar 4G mobile data quota and/or pricing revisions in Norway, Hong Kong, and the US," said Jake Saunders, VP for forecasting at ABI Research.

According to ABI Research's cross-country comparison of mobile data pricing, the world's cheapest 4G data plan is currently on offer by CSL Hong Kong, which launched its 4G service in November 2011.

"4G technology has given operators not just greater download speeds but also greater capacity. Therefore, there is a degree of price elasticity," added Marina Lu, research associate, ABI Research. "As 4G devices come down in price, operators will be keen to increase 4G market-share. Cutting tariffs, or boosting data quotas, will be tempting but they need to make sure they achieve greater overall returns. "

Meanwhile, voice tariffs are also benefiting from LTE. A number of operators are rolling out Voice over LTE (VoLTE). The higher fidelity offered by VoLTE could help overcome the decline in voice-related ARPU, said ABI Research. And, VoLTE is not being priced at a premium over existing circuit switched mobile voice services.