Systems, methods, and instrumentalities are disclosed for non-orthogonal multiple access (NOMA), frequency hopping, and power control. NOMA may be applied to asynchronous and/or grant-free transmissions. Transmissions from multiple WTRUs may be performed using the same resources, and may comprise information for correctly identifying and decoding the transmissions. The transmissions may comprise a built-in deterministic sequence to support timing acquisition at a receiver. The transmissions may be distinguished based on respective transmit power used for the transmissions. Such transmit power may be dynamically controlled by applying a randomly selected power offset. The power control may be performed autonomously by a WTRU.