Jeong Gon Kim

An effect of delay reduced MAC protocol for WBAN based medical signal monitoring

Due to the recent development of medical and wireless communication technology, the WBSN application is gradually increased to personal healthcare monitoring. WBSN is a network e where various kinds of bio signals of the body are measured and then are processed and transmitted to neighboring monitoring and personal portable devices. WBAN is a kind of network standard for supporting various connection around human body within 2 ~ 3 m which consists of medical and non-medical devices. The MAC Protocol proposed in this paper applies the delay limitation to MAC Protocol in medical signal monitoring to reduce the time delay and packet loss in TDMA based CSMA/CA environment. The proposed MAC protocol consider the priorities of several bio signals with different characteristics and sets up minimum packet delay time in order to guarantee the data effectiveness. Simulation results show that the proposed MAC protocol attains the reduced time delay and less packet loss over conventional Bio MAC protocol in WBAN based some medical signal monitoring network environment.

A Study for Co-channel Interference Cancelation Algorithm with Channel Estimation for WBAN System Application

In this paper, we analyze and compare several co-channel interference mitigation algorithms for WBAN application in 2.4 GHz ISM frequency bands. ML (Maximum Likelihood), OC (Optimal Combining) and MMSE (Minimum Mean Square Error) has been considered for the possible techniques for interference cancellation in view of the trade off between the performance and the complexity of implementation. Based on the channel model of IEEE 802.15.6 standard, simulation results show that ML and OC attains the lower BER performance than that of MMSE if we assume the perfect channel estimation. But, ML and OC have the additional requirement of implementation for his own and other users`s channel estimation process, hence, besides the BER performance, the complexity of implementation and the sensitivity to channel estimation error should be considered since it requires the simple and small sized equipment for WBAN system application. In addition, the gap of detection BER performance between ML, OC and MMSE is much decreased under the imperfect channel estimation if we adopt real channel estimation process, therefore, in order to apply to WBAN system, the trade off between the BER performance and complexity of implemetation should be seriously considered to decide the best co-channel interference cancellation for WBAN system application.

Joint ZF and partial ML detection for uplink cellular base station cooperation

In this paper, we address the issue of joint detection schemes for uplink cellular system when base station cooperation is possible for multi-cell users in multi-cell scenario. The ZF and ZF based SIC detection are analyzed and evaluated, however, they need the increased decoder complexity as the number of iteration is increased. We propose a new joint ZF and partial ML decoding scheme, which combines the ZF detection and partial ML decoding scheme in order to improve the detection performance and also decrease the decoder complexity. Simulation results show that the proposed scheme attains the better BER performance and also provide a much reduced decoder complexity The proposed scheme can be applied to the MIMO detection for single user and can be extended to multiuser and multi-antenna based other types of BS Cooperation.

Improved scheduling for MAC protocol in WBAN based monitoring environment

Recently, the application range of WBAN has been gradually expanding due to the advanced wireless telecommunication techniques and the activated ubiquitous environment. WBAN is a network environment in which various types of medical or non-medical signal created directly or indirectly in and out of the body are measured and processed for transmission to various mobile device nearby. The MAC protocol proposed in this paper is in form of TDMA based technique in CSMA/CA environment. The proposed scheme applies the maximum delay restriction to each type of data packets in order to deal with the delayed packets due to the collision from the transmission of two or more packets at the same time. We compare the packet delay with the random selection based scheme according to the variation of total offered data traffic. The effect to the packet delay is analyzed in case we consider the delay requirement and the adaptive scheme is needed to cope with the high and mixed data traffic in future WBAN based network environment.

Resource allocation with LBS information for cellular based D2D communication networks

D2D (Device-to-Device) communication is emerging technique to increase resource utilization and spectrum efficiency. However, D2D communication has a problem that the efficiency decreases due to interference is increased. we propose a resource allocation scheme to decrease interference. D2D communication utilizes the location information and SINR (Signal-to-Interference-plus-Noise Ratio). In this case, eNB (eNodeB) know the location of all devices. The proposed scheme ensures performance of the D2D communication when the D2D link share the resources of the cellular network in the uplink. Simulation results show that the proposed scheme has the throughput better than scheme with location information.

MAC Protocol with Priority to Urgent Data in Wireless Healthcare Monitoring Sensor Networks

The WBSN is a network environment in which various types of bio-signals generated directly or indirectly inside and outside the body are measured and processed for transmission to monitor the condition of the patient. The conventional DTD (Decrease of Transmission Delay)—MAC protocol transmits general and emergency data without any classification. As a result, the average delay and packet loss rate increase. Hence, in order to mitigate this performance degradation, we propose two types of adaptive MAC protocols to deal with emergency data separately in the system. The first proposed protocol reduces the delay by prioritizing emergency data over other general data by sending them first. The second proposed protocol applies the maximum delay requirement to emergency data to reduce the packet loss of both general and urgent data packets at the same time.

Resource Allocation in D2D Networks with Location Based Distance Information

Recently, mobile internet traffic has rapidly increased as the huge increase of the smart phone and mobile devices. D2D (Device to Device) is known that it reduce the traffic load of the base station and also improves the reliability of the network performance. However, D2D has a problem that the efficiency decreases as interference is increased. In this paper, we propose a resource allocation scheme to use the resources efficiently when the D2D link share the resources of the cellular network in the uplink. D2D communication utilizes the location information for allocating resources when the eNB know the location of all devices. The proposed scheme not only ensures the performance of the D2D communication but also decrease the computational complexity Simulation results show that the proposed scheme attains the comparable throughput over optimal scheme with a very small computational complexity.

Joint ML & MMSE-SIC detection for multi cell network environment

In this paper, we address the issue of the joint detection schemes for uplink cellular system when base station cooperation is possible for multi-cell users in multi-cell scenario. The ML, MMSE and MMSE based SIC detection are analyzed and evaluated. ML attains the optimal performance but the complexity increases exponentially. MMSE is simple but has poor detection performance and SIC has better performance but it has large complexity and the potential of the error propagation. We propose a new ML and MMSE-SIC detection scheme, which combines the partial ML decoding and MMSE based SIC combined detection in order to improve the uncoded BER performance and also decrease the decoding complexity. Simulation results show that the proposed scheme attains the maximum 2 dB reduction of required SNR value to achieve the same BER performance and a similar or a little bit reduced level of decoder complexity over the MMSE based SIC scheme. The proposed scheme can be applied to the MIMO detection for single user and can be extended to other types of multi-user and multi-antenna based BS Cooperation.