ABS Scheduling Technique for Interference Mitigation of M2M Based Medical WBAN Service

A wireless body area network (WBAN) is a technology for transmitting relevant device data from information terminals attached to the body. Since it does not need connection lines, it is more convenient than a wired communications system. It is better than conventional wireless communications in terms of security, power efficiency, and data transmission speed. A medical WBAN for health care consists of a sensor, an actuator, and a communications module, and is connected to a wireless network. Because it moves with people, a medical WBAN device attached to the body features network mobility. When a medical WBAN sensor uses multiple channels, it needs to choose the channel with the best data transmission rate in order to send urgent data related to a patient's life, which is very important. Therefore, significant and urgent data should be transmitted faster than other data that are less important. However, medical WBAN devices have different frequency bandwidths, so there are heterogeneous networks, which can result in a serious problem. In such a case, to send data smoothly, it is necessary to calculate the delay time of a transmission channel and choose a channel with the best performance in order to send urgent data. But in choosing a channel, conventional data transmission selection only takes into account transmission speed and data transmission volume. In that case, to calculate an accurate delay time for a real transmission channel, it is necessary to compute delay time, which reflects retransmission according to the error rate caused by interference on the transmission channel. It is necessary to employ an optimal data transmission selection method when it comes to urgent data transmission. Therefore, in this paper, we propose an almost blank subframe (ABS) scheduling technique for interference mitigation under a machine-to-machine-based medical WBAN. For implementation of the proposed algorithm, this study proposes a scenario with a medical WBAN and a distributed structure to recognize the effect on a WBAN device's processing volume, and we designed a heterogeneous network system. For system simplification, the load occurring on the system can be defined as the user rate in a cluster. For algorithm reliability, it was defined as an 8-basis frame. In addition, to dynamically balance the load between the health gateway and the WBAN device user, this paper also proposes a high-speed load balancing algorithm. The proposed algorithm means that a selective subframe is used as a normal subframe or a mandatory ABS according to the load of the health gateway and the WBAN gateway, and overall performance is improved through an efficient offload of the health gateway. In this case, the reference signal received power difference between the health gateway and the WBAN gateway layer is measured. If specific user equipment receives more power signals from the WBAN gateway than from the health gateway, it is a RE WBAN device; otherwise, it represents a central WBAN device. Also, in this paper, devices of each site prefer reference signal received quality-based cell selection for a smooth process. If carrier aggregation is not smoothly applied to each site, inter-site interference can occur. Therefore, by applying ABS to carrier aggregation, it is possible to improve performance.