A storage apparatus has a storage structure with at least a part thereof being formed to have and maintain a non-flat configuration during use. obtaining a channel estimation result of at least one terminal expecting a calculation of DOA in an expecting co-frequency cell; B. The bedding is kept neatly inside the transparent container until the user wants to use the bedding therein. The device is inexpensive to produce, and readily adaptable for a broad range of clasping applications that include temporarily holding and securing light weight objects. In a fourth step, at least one of an upper and a lower bound for the certain metric is retrieved in dependence on the stored positions and the stored values of the coefficients having the largest energy and the determined compression errors.