  This paper presents a feasibility study for a novel positioning-communication
integrated signal called Multi-Scale Non-Orthogonal Multiple Access (MS-NOMA)
for 5G positioning. One of the main differences between the MS-NOMA and the
traditional positioning signal is MS-NOMA supports configurable powers for
different positioning users (P-Users) to obtain better ranging accuracy and
signal coverage. Our major contributions are: Firstly, we present the MS-NOMA
signal and analyze the Bit Error Rate (BER) and ranging accuracy by deriving
their simple expressions. The results show the interaction between the
communication and positioning signals is rather limited, and it is feasible to
use the MS-NOMA signal to achieve high positioning accuracy. Secondly, for an
optimal positioning accuracy and signal coverage, we model the power allocation
problem for MS-NOMA signal as a convex optimization problem by satisfying the
QoS (Quality of Services) requirement and other constraints. Then, we propose a
novel Positioning-Communication Joint Power Allocation (PCJPA) algorithm which
allocates the powers of all P-Users iteratively. The theoretical and numerical
results show our proposed MS-NOMA signal has great improvements of
ranging/positioning accuracy than traditional PRS (Positioning Reference
Signal) in 5G, and improves the coverage dramatically which means more P-Users
could locate their positions without suffering the near-far effect.
