TECHNICAL FIELD

The disclosure relates generally to wireless communications and, more particularly, to systems and methods for using a random access channel.

BACKGROUND

In accordance with rapid developments and increasing needs of the Internet of Things (IoT), a new radio interface, a Narrowband Internet of Things (NB-IoT), has been proposed by the 3rd Generation Partnership Project (3GPP). The NB-IoT is aimed to enhance existing Global System for Mobile Communications (GSM) and Long-Term Evolution (LTE) networks to better serve IoT uses or applications. Improved indoor coverage, support for massive number of low throughput end devices, low delay sensitivity, ultra-low device cost, coverage extension, battery lifetime extension, and backward compatibility are some exemplary objectives of the NB-IoT.

Generally, in a wireless communication system adopting the NB-IoT (hereinafter “NB-IoT system”), a user equipment device (UE) sends at least one preamble signal (hereinafter “Preamble”), typically via a Physical Random Access Channel (PRACH), to a base station (BS) to initiate a contention-based random access procedure. Such a Preamble is used as a temporary identity of the UE for the BS to estimate various information, e.g., Timing Advance (TA) command, scheduling of uplink resources for the UE to use in subsequent steps, etc., such that the UE may use the above-mentioned information to finish the random access procedure.

However, it has been noted that using legacy formats of the Preamble may encounter a variety of issues such as, for example, wrong estimation of the TA command when a respective coverage of the BS extends beyond 100 kilometers in radius (typically known as a “cell”), strong interference among plural neighboring cells, etc. Although some different Preamble formats (hereinafter “non-legacy Preamble formats”) have been proposed to resolve at least some of the aforementioned issues, in the existing NB-IoT system, the UE's cannot differentiate the legacy Preamble formats and aforementioned “non-legacy” Preamble formats, which may disadvantageously limit various potential applications of the NB-IoT system. Accordingly, the existing NB-IoT system is not entirely satisfactory.

SUMMARY OF THE INVENTION

The exemplary embodiments disclosed herein are directed to solving the issues relating to one or more of the problems presented in the prior art, as well as providing additional features that will become readily apparent by reference to the following detailed description when taken in conjunction with the accompany drawings. In accordance with various embodiments, exemplary systems, methods, devices and computer program products are disclosed herein. It is understood, however, that these embodiments are presented by way of example and not limitation, and it will be apparent to those of ordinary skill in the art who read the present disclosure that various modifications to the disclosed embodiments can be made while remaining within the scope of the invention.

In one embodiment, a method performed by a wireless communication node includes: broadcasting at least one message indicating first and second formats. The first format is used by a plurality of wireless communication devices to send respective first random access preambles and the second format is used by the plurality of wireless communication devices to send respective second random access preambles. The first and second formats respectively correspond to first and second cell coverage ranges of the wireless communication node, the second cell coverage range being greater than the first cell coverage range.

In a further embodiment, a method performed by a wireless communication device includes: receiving, from a wireless communication node, at least one broadcasted message indicating first and second formats. The first format is used by the wireless communication device to send a respective first random access preamble to the wireless communication node and the second format is used by the wireless communication device to send a respective second random access preamble wireless communication node. The first and second formats respectively correspond to first and second cell coverage ranges of the wireless communication node, the second cell coverage range being greater than the first cell coverage range.

