As mobile providers prepare to sink billions of dollars into the next generation of wireless networking, or 5G, engineers are still scrambling to nail down its technical details but were able to take key steps needed to start rolling out the network by the end of this year.

The bottom line: The group left La Jolla with the features for the standards of its first version frozen and a solid start on the standards for the follow-on release, albeit with technical work yet to be done on all fronts.

Why it matters: The industry wants to have networks up and running by the end of this year and early next year, with mainstream 5G phones on sale by the spring.

What's happening: At a meeting last week in La Jolla, Calif., engineers from the world's biggest networking companies gathered to work out remaining issues and plan for the releases that will follow the first one that consumers will start using early next year.

The key issues: The groups were working against a deadline to finalize the first version of 5G that will power mobile networks starting in early 2019, known as Release 15.

In addition, a lot of focus was on Release 16, the next version of 5G that will cover a broader range of devices. Release 16 will build on the initial version and deal with specific-use cases like Internet of Things and broader applications like telemedicine and virtual reality that call for a system with very minimal delay.

Who was there: It was a global group, including representatives from networking vendors like Nokia, Ericsson and Huawei, chipmakers including Qualcomm and Intel, and device makers such as Apple, LG and Oppo. It also included carriers like AT&T, Sprint and T-Mobile plus global counterparts such as Deutsche Telekom, Vodafone, China Unicom and China Mobile.

The setting: At a Marriott outside San Diego, representatives gathered in separate groups to go through reports from various working groups, debate a few items and decide which matters can still be tackled in time to make the initial release. There were maybe two dozen women along with more than 300 men.

Highs and lows: The emotional peak came Wednesday night as the group members voted to freeze changes to Release 15. Yet things got testy by Thursday morning as debate bogged down over how a particular roaming feature is being implemented in Release 16.

Some felt this was a business issue that should be handled outside of the standards group, while others said there were technical issues that needed to be addressed.

What they're saying: