IPA IP 2022 Question 92

A question IPA Japan published in 令和4年度 ITパスポート試験公開問題問92, translated into English. ITPEC is based on the same exams.

BLE, which is used for communication in IoT area networks and other such purposes, is a specification that was added in Bluetooth 4.0. Which of the following is an appropriate description concerning BLE?

a)It has become possible for it to communicate also with Wi-Fi access points.b)Its power consumption is so low that continuous operation for half a year to several years is possible on a common button battery.c)It is compatible with Bluetooth 3.0 and earlier, which are the conventional standards.d)Infrared can also be used for communication with devices.

Explanation

Low enough power to run for months or years on a button battery — BLE (Bluetooth Low Energy) was added in Bluetooth 4.0 for small IoT devices that send little data.

BLE keeps the radio asleep most of the time and wakes it only briefly to send small amounts of data, so a sensor, a beacon or a wearable device can run for half a year to several years on one coin-shaped button battery. That makes it a common choice for the short-range IoT area network between devices and a smartphone or gateway, while LPWA covers distances of kilometres.

Answer (b)

Why not others:

•(a) — BLE is a Bluetooth specification and talks to Bluetooth devices; a Wi-Fi access point uses the IEEE 802.11 wireless LAN standards, which BLE does not speak
•(c) — BLE uses a different radio protocol from the classic Bluetooth of version 3.0 and earlier, so a BLE-only device cannot talk to a classic-only one; only dual-mode devices support both
•(d) — Bluetooth, BLE included, uses radio waves in the 2.4 GHz band; infrared communication is IrDA

Key rule: BLE trades data rate for very low power consumption and is not compatible with classic Bluetooth; it is radio in the 2.4 GHz band, unlike infrared IrDA.

Networks · AI-written, may contain errors

Previous Next

Practice this exam

This question comes from the past questions IPA Japan publishes, translated into English by ITPEC Practice. ITPEC Practice is an independent study tool and is not affiliated with IPA or ITPEC. See the original paper (PDF) or Report an issue.