Japan's top wireless operator NTT DoCoMo Inc is easing the pace of its M&A activity in Asia as it focuses on existing acquisitions, an executive said.

Cash-rich DoCoMo, which is still hungry to grow in Asia through investments in operators, wants to first solidify its services with India's Tata Teleservices TATASL.UL and with Philippines Long Distance Telephone Co, senior executive vice president Kiyoyuki Tsujimura said on Thursday.

We can't keep on investing in one company after another, he said in an interview with Reuters. We have to stop and develop manpower and services first. Then we can invest in the next deal.

DoCoMo controls half of Japan's saturated mobile market, where growth has stalled. It is now looking at investing in more software firms and content providers that could help DoCoMo raise revenues when it launches its Long Term Evolution network at the end of next year.

DoCoMo considers the arrival of LTE, which allows faster uploads and downloads to mobile devices, a second chance after it fumbled its push to gain global presence with its 3rd-generation phone network 10 years ago, launching its network too early.

It also hopes that foreign phone makers will buy an LTE chip set it developed with NEC Corp, Panasonic Corp and Fujitsu Ltd, even though this faces stiff competition from chipmakers Qualcomm and ST-Ericsson, Tsujimura said.

LTE would allow users to store more data in servers instead of in their phones.

DoCoMo's recent acquisitions include a 35 percent stake in NexWave Wireless Inc's software unit PacketVideo, aimed at shoring up its music and video services.

DoCoMo's capex in LTE base stations and the network between April 2010 and March 2015 could exceed the currently planned 300 billion yen to 400 billion yen ($3.4 billion to $4.5 billion) if demand is strong enough, Tsujimura added.

Prior to the news, DoCoMo's shares closed down 1 percent, while those of No.2 Japanese carrier KDDI Corp fell 2.6 percent and third-ranked Softbank Corp rose 1.6 percent.

($1=88.30 Yen)

(Editing by Joseph Radford)