Google has started to roll-out over-the-air Android 4.1 Jelly Bean updates, with HSPA+ Galaxy Nexus devices getting the upgraded operating system first.

The company then plans to upgrade the software on the rest of the Galaxy Nexus models, Nexus S smartphone and Motorola Xoom tablets. The Google Nexus 7 7-inch tablet will ship with the OS pre-installed later this month.

Jelly Bean, says Google, features a faster interface and better search functionality (over Ice Cream Sandwich). Voice Search is also speedier, and Google Now is part of the upgraded Google app.

Google says it has improved Voice Search so that it can display answers to spoken questions from sources including Wikipedia, the CIA World Factbook and Freebase – a community-run knowledge database.

It has also introduced Google Now which is designed to offer information without the user having to actively trigger a query.

Both features are potentially in breach of an integrated search patentfiled by Apple.

Last December the US Patent and Trademark Office granted the iPhone maker intellectual property rights to the idea of gathering search results.

A US court imposed a sales ban on the Galaxy Nexus in the country last week following a complaint by Apple that Samsung had infringed the patent by including integrated search functionality in the handset.

Although the restriction was later lifted there had been reports that Google would alter Android to restrict its quick-search and voice-search facilities to web-based results.

Google Now keeps you updated on points of interest, such as the weather, sports results, traffic alerts, that sort of thing. It aims to give you this information just as you need it, such as the traffic updates before you set off for work. Jelly Bean also adds a new, smarter keyboard to the mix.

HSPA+ Google Nexus owners will start to receive update alerts over the coming few days. There is currently no word on when Jelly Bean updates may start for Android handsets outside of the immediate Google family.