Samsung Electronics this week unveiled what it said was the first smart-watch capable of making and receiving calls without a mobile phone nearby.The world's biggest smartphone maker has been pushing hard to develop the wearable devices market as it looks to counter slowing earnings in its mobile division.The South Korean firm is hardly alone in pushing wearables, which have yet to catch on with consumers. Rival Apple is expected to launch its own device this year and LG Electronics on Thursday announced its new G Watch R smartwatch featuring a circular plastic OLED screen, a stainless steel frame and leather strap.Samsung's new smartwatch, called the Gear S, differs from its predecessors with a bigger 5cm curved display and offers features like WiFi connectivity, pedestrian navigation and a built-in GPS. This device will run on Samsung's nascent Tizen operating system.Samsung said the Gear S will start selling from October. LG said its G Watch R will launch in key markets in the fourth quarter. Prices of both devices will be announced later.