July 2018 doc IEEE 802 15 18 0115

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep Project: IEEE P 802. 15 Working Group for Wireless Personal Area Networks (WPANs) Submission Title: [IG DEP A dependable MAC protocol matched to bi-directional transmission for dependable wireless body area network (WBAN)] Date Submitted: [10 July 2018] Source: [Toshikuni Miyazaki 1, Ryuji Kohno 1, 2, 3] [1; Yokohama National University, 2; Centre for Wireless Communications(CWC), University of Oulu, 3; University of Oulu Research Institute Japan CWCNippon] Address [1; 79 -5 Tokiwadai, Hodogaya-ku, Yokohama, Japan 240 -8501 2; Linnanmaa, P. O. Box 4500, FIN-90570 Oulu, Finland FI-90014 3; Yokohama Mitsui Bldg. 15 F, 1 -1 -2 Takashima, Nishi-ku, Yokohama, Japan 220 -0011] Voice: [1; +81 -45 -339 -4115, 2: +358 -8 -553 -2849], FAX: [+81 -45 -338 -1157], Email: [1: kohno@ynu. ac. jp, 2: Ryuji. Kohno@oulu. fi, 3: ryuji. kohno@cwc-nippon. co. jp] Re: [] Abstract: [As a dependable MAC protocol for wireless body area network(WBAN), a scheme of media access control specified for bi-directional transmission of related packets between a coordinator and nodes of is introduced. ] Purpose: [information] Notice: This document has been prepared to assist the IEEE P 802. 15. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor acknowledges and accepts that this contribution becomes the property of IEEE and may be made publicly available by P 802. 15. Submission Slide 1 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep A dependable MAC protocol matched to bi-directional transmission for dependable wireless body area network (WBAN) Toshikuni Miyazaki*, Ryuji Kohno*† ＊Graduate School of Engineering Yokohama National University † University of Oulu Research Institute Japan – CWC-Nippon, Co. Ltd. Submission Slide 2 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep Agenda 1. Background 2. Aim of This Study for MAC Protocol of WBAN 3. Modified MAC of IEEE 802. 15. 6 for Bi-transmission Packets 3. 1 M-EAP(Modified-EAP) 3. 2 G-Slot(Guaranteed Slot) 4. Performance Evaluation 5. Simulation Results 6. Conclusion 7. Reference Submission Slide 3 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWCNippon)

まとめと今後の課題 高信頼実現に向けた提案 July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep 1. 　Background 1. 1 WBAN(Wireless Body Area Network) Wireless Body Area Network(BAN) have been designed and developed for specific applications to wearable and implanted devices such as remote monitoring sensors and controlling actuators. Fig. 1 System Configuration of Intra-, Inter-, and Beyond-WBAN Physical and MAC Layers Specification of WBAN have been internationally standardized such as IEEE 802. 15. 6 in Feb. 2012 ❖ This study is focused to improve MAC protocol of the existing BAN standard to be more dependable. Submission 4 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

双方向通信に対する提案 高信頼実現に向けた提案 July 2018 まとめと今後の課題 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep 1. 2. 　Protocol of MAC Layer ❖ MAC(Medium Access Control) Layer Fig. 2 Two Types of Major MAC Protocols; Contention based and Contention free ❖ IEEE 802. 15. 6 WBAN MAC is aprotocols hybrid procol between contention free and based protocols to keep advantages of flexibility corresponding variant traffic and guarantee delay time. Submission 5 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

双方向通信に対する提案 高信頼実現に向けた提案 July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep 1. 3. 　MAC of Existing Standard for WBAN; IEEE 802. 15. 6 ❖ Specification of MAC Protocol B(Beacon) For synchronization and Superframe structure EAP(Exclusive Access Phase) Contention base access period for only specific packets RAP(Random Access Phase) Contention base(CSMA/CAやSlotted ALOHA) MAP(Managed Access Phase) Contention free(TDMAやPolling/Posting) Fig. 3 Standardized Packet Access Controlling Time Strucuture (Beacon mode with superframes) Since WBAN has a star topology between a central controlling coordinator and nodes, both contention base and free protocols are applicable. Fig. 4 Network Topology of WBAN (Star topology + one hop relay) ❖ WBAN standard IEEE 802. 15. 6 is Hybrid MAC protocol to match with different priorities or Qo. S levels of packets with various traffic conditions. Submission 6 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep 2. Aim of this proposed MAC protocol ❖ About Latency of Transmission In WBAN, not only mean performance, but also worst case(variance value) Worst Case In addition, permissible value* ❖ Efficiency of Transmission Channel Utilization Delay Not to waste the transmit chance, Assign transmit slot adaptively ❖ Bi-directional Transmission In WBAN MAC, both uplink and downlink is supported, For instance, a command packet to control injecting insulin to wearable pump corresponding to packets of sensed glucose levels from sensor nodes. therefore, have to consider the features of downlink traffic ❖ In this study, focus on these contents *：IEEE P 802. 15 Wireless Personal Area Networks, "TG 6 Technical Requirements 　 Document (TRD), "IEEE P 802. 15 -08 -0644 -09 -0006, November 2008. Submission Slide 7 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep Bi-directional transmission model Table. Benchmark of bi-directional model Including emergency frame(UP 7) Parameters Uplink Downlink Payload length Short~Long* Short Interval of frame generation Low~High* Low Priority Low~High* Highest * : Depends on the types of node Table. Relation between UP(User Priority) mapping and control frame(Downlink) Downlink frame based on all levels Fig. A example of feedback model Submission Slide 8 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep 3. Modified MAC of IEEE 802. 15. 6 Table. Modified UP mapping for bi-directional transmission l Control frame is calculated and transmitted based on sensing frames which include medical and emergency traffic − Change the UP class like table l EAP is set in hybrid superframe structure in IEEE 802. 15. 6 based on UP mapping and allow to transmit only emergency frames(or implant event report) − For this reason, in general, this phase becomes like a reserve field and performance in MAC layer(i. e. latency, throughput) decrease l We proposed M-EAP(Modified-EAP), which is allowed to transmit both emergency and control frame of downlink. − Become more busy phase than EAP, so the performance can be improved − Adapt to priority control based on modified UP mapping − In case, if frame collision occurred between uplink and downlink traffic, coordinator node can find the frame collision based on the feature of acknowledge l This proposal scheme, M-EAP, is based on contention base, therefore it cannot guarantee the permissible values based on Pcollision Submission Slide 9 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep G-Slot algorithm in order to achieve the dependability l Proposal scheme, G-Slot(Guaranteed Slot), is based on scheduled access and considered GTS(Guaranteed Time Slot: IEEE 802. 15. 4) method as reference in order to adapt to WBAN MAC protocol. Fig. GTS algorithm in IEEE 802. 15. 4 Fig. Relation between G-Slot and MAP l Branch condition in Figure is as follows; • If control frame (downlink traffic) is or not • Emergency frame is or not − Especially, when a node transmits frame with emergency, the others also transmits frames with emergency because human behavior is consist of a lot of parameters. • Superframe number is odd or even − In order to achieve the permissible value certainly, the transmission slot assignment interval becomes less than 125 ms or 250 ms. In this method, we set the superframe length less than 125 ms, so this branch condition is. l We propose from the sight of both contention base and free Submission Slide 10 Fig. G-Slot algorithm in MAP Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep 3. 1. PROPOSAL METHOD 1 ❖ M-EAP(Modified-EAP) Consider the standard EAP method as reference in order to adapt to downlink transmission and efficiency of channel utilization ❖ Aim : Decrease the frame collision than RAP, Improve throughput M-EAP ü Transmit emergency frame and downlink frame(control info. ) ü Become more busy phase than standard EAP phase ü Transmit only emergency frame ü In case collision between emergency and downlink frame, coordinator can recognize ü In case collision in this phase, coordinator cannot recognize ü This phase rarely becomes busy, like a reserve phase in every superframe ❖ In both M-EAP and EAP, they cannot guarantee the permissible value(latency), because of contention based protocol Submission Slide 11 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep 3. 2 PROPOSAL METHOD 2 Consider GTS(Guaranteed Time Slot : IEEE 802. 15. 4) method as reference in order to adapt to WBAN MAC protocol ❖ G-Slot(Guaranteed Slot) ü In order to guarantee the downlink, emergency frame, and permissible value, change the transmit slot assignment ※ In my current study, defined superframe length as fixed 121. 5 ms MAP ❖ Using M-EAP, this algorithm and proposal transmit slot(G-Slot), achieve dependable MAC protocol Submission Slide 12 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep 4. 1 Evaluations using M-EAP and G-Slot l Condition in this simulation • Control frames are calculated and transmitted when coordinator node received 10 frames by each node(No. 4~6) • Control frame can transmit in only M-EAP and G-Slot This phase is defined inactive in this simulation Fig. Superframe structure for bi-directional transmission model Fig. Network structure for bi-directional transmission model Table. Modified UP mapping for bi-directional transmission Table. Simulation parameters The number of node Sensor nodes： 6 Coordinator node： 1 Payload length of control frame 8 octets Size of transmission slot in MAP 5. 5 msec. Superframe length 120. 5 msec. Submission Slide 13 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep 4. 2 Results of worst latency and throughput l Latency performance − Proposal method can assign the transmission slot to each node in every superframe adaptively by using G-Slot, therefore, achieve the permissible values. This algorithm is based on TDMA: Fig. Worst latency in bi-directional transmission model Fig. Throughput evaluation in active condition Submission l Throughput performance − In this study, throughout is evaluated by using MAC payload length − G-Slot algorithm set the transmission slot in MAP as needed. In other words, this algorithm decreases the waste slots. − For fairness comparison, except the inactive phase to calculate throughput, called active condition. − Proposal scheme becomes busier than standard by using M-EAP, and decreases the waste slot by using G-Slot. It means that efficiency of transmission channel utilization of proposal scheme became higher than standard. Slide 14 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep 4. 3 Considering the superframe ratio l Both proposal methods, M-EAP and G-Slot will not be good performance in some cases. One of the big factor is network offered load like Figure. l G-Slot algorithm can decrease the waste slot, but the number of assignable transmission slot is limited if the MAP length is fixed. Therefore, its performance in high offered load condition become worse. − In order to improve its performance, consider the superframe ratio which is specific issue in hybrid MAC protocol and not considered in IEEE 802. 15. 6 about. Fig. Drawback of proposal scheme vs. offered load Submission Slide 15 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep 4. 4 Defines the borders of extreme conditions (using superframe which is composed of only MAP) Fig. Border of low extreme condition l These borders are calculated by using simulation parameters in this study. The upper higher border is set as about 180 packet/s for only MAP superframe structure and lower border is set as about 60 packet/s for only RAP superframe structure. l These conditions are calculated by using only MAC layer. Submission Slide 16 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep 5. SIMULATION PARAMETER ❖ Simulation Parameters and Condition Table 2. Modified User Priority Mapping Table 1. Parameters parameters values The number of node Medical(3), Nonmedical(3), Coordinator(1) Topology One-hop-star Superframe length 120. 5 [ms] Uplink payload 128 [octets] Emergency frame probability (※ 1) Downlink payload 8 [octets] Control frame generate (※ 2) MAP Slot length 5. 5 [ms] Total Offered Load 60 [packet/s] Frequency Narrow band(2. 4 [GHz]) Trial times 1000 [times] Inactive phase Fig. 1. Length of each phase in proposal superframe Fig. 2. Network topology Submission Slide 17 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep 5. PERFORMANCE EVALUATION ❖ Worst Case Evaluation ※ Mean performance evaluations show in appendix Traffic condition ※ Network traffic is nonsaturated condition Fig. 3. Performance evaluation of worst delay ❖ Especially, using G-Slot assignment algorithm, guarantee the worst case, in other words, become dependable MAC protocol Submission Slide 18 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep 5. CONT’D ❖ Throughput Evaluation(Comparison with Standard MAC Protocol) Standard MAC protocol ※ Use EAP for emergency and TDMA for Managed Access Phase Comparison ※ To evaluate under the same condition, define the word, active condition Active condition ※ This condition is defined as the condition which is removed inactive period Fig. 4. Performance evaluation of throughput in active condition ❖ Especially, using M-EAP and G-Slot assignment algorithm, network throughput become higher than standard MAC protocol Submission Slide 19 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep 5. Modification ❖ About Ratio MAP Define the ratio as the length of each phase in superframe RAP Superframe Fig. 5. Example of ratio in superframe ❖ Points of Similarity in Superframe Ratio Pattern 1 : MAP Inactive RAP Pattern 2 : MAP Inactive RAP Fig. 6. Example of transmit slot assignment patterns in MAP is consist of Active transmit slot and Inactive by G-slot algorithm ❖ Consider this ratio in response to offered load for WBAN Submission Slide 20 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep 5. 2 Evaluation Parameters Definition ❖ Limitation of Upper Offered Load ❖ Values in This Study(Reference of Table 1) Submission Slide 21 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep 5. 2 CONT'D ❖ Analysis in Low Offered Load Condition These graphs show the worst delay time in response to offered load using superframe which consists of only RAP Fig. 7. Worst delay time using superframe which consists of only RAP Like fig. 7, it is indeed RAP cannot guarantee the permissible value, but this satisfies this value in the condition which less than 60 packet/s ❖ Therefore, consider this 60 packet/s as upper limit for only RAP superframe structure Submission Slide 22 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep 5. 3 ALGORITHM FOR OFFERED LOAD CONDITION ❖ Ratio Definition Algorithm for Superframe Structure Superframe ratio Traffic estimation The others Middle condition Low condition High condition Only RAP Only MAP この結果を途中段階として次のスライドより示す (Simulation ParametersはTable 1. を再度参照) ❖ I show the results in low and high offered load condition Submission Slide 23 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep 5. 3 STANDARD METHOD FOR COMPARISON ❖ Difference Between Proposal and Standard Method Fig. 8. Superframe structure of IEEE 802. 15. 6 ü UP for downlink traffic, like control info. ❖ Define the condition of standard method like this slide, and show comparison from next slide * : IEEE Computer Society, ”IEEE standard for local and metropolitan area networks part 15. 6: Wireless Body Area Networks, ”pp. 1257, 29 February 2012. Submission Slide 24 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep 5. 4 PERFORMANCE EVALUATION ❖ Throughput Evaluation in comparison with IEEE 802. 15. 6 Low offered load condition High offered load condition Fig. ９. Throughput comparison between proposal method and standard ❖ In next slide, show the results of latency and transmission success rate Submission Slide 25 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep 5. 4 PERFORMANCE EVALUATION ❖ Mean Latency and Transmission Success Rate Comparison In this study, divergence of latency is not considered in delay evaluation. The event is evaluated in transmission success rate Fig. 10. Mean delay time and transmission success rate comparison between proposal method and standard ❖ In next slide, I explain the algorithm of traffic estimation Submission Slide 26 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 5. 5 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep ALGORITHM FOR OFFERED LOAD CONDITION ❖ Ratio Definition Algorithm for Superframe Structure (see above) Superframe ratio この結果を途中段階として次のスライドより示す (Simulation ParametersはTable 1. を再度参照) Traffic estimation The others Middle condition High condition Low condition Only RAP Empty slot If coordinator node assigned transmission slot to nodes, the slot became idle Filled slot If …, the slot became busy Only MAP ❖ I propose to use the relation between empty and filled slot in MAP in order to divide into conditions Submission Slide 27 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep 5. 6 EMPTY SLOT IN SUPERFRAME WITH ONLY MAP ❖ The Relation Between Empty and Filled Slot (See above shown in Fig. 7) Fig. 11. The relation between empty and filled slot in only MAP superframe Even if empty slot is larger than filled slot in superframe with only MAP, permissible value is not achieved ❖ In order to achieve both high performance and dependability in WBAN, have to consider these features Submission Slide 28 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep 5. 6 EMPTY AND FILLED SLOT ❖ Relation Between Empty and Filled Slot in MAP Fig. 12. The relation between empty and filled slot in only MAP superframe Submission Slide 29 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep 5. 7 ALGORITHM FOR OFFERED LOAD CONDITION ❖ Ratio Definition Algorithm for Superframe Structure (see above) Superframe ratio Traffic estimation The others Middle condition Extended G-Slot High condition Low condition ** : Slide 9 Only RAP Only MAP G-Slot structure** ❖ Like fig. 12, superframe structure algorithm is defined based on performance and dependability Submission Slide 30 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep 5. 7 EXTENDED G-SLOT STRUCTURE ❖ About Extended G-Slot Structure i. Use the superframe with only MAP structure Empty transmission slot Filled transmission slot iv. Additional slot This transmission slot is assigned to medical nodes as priority Define the superframe structure Submission Slide 31 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep Simulation results ❖ Throughput performance Definition of throughput of this evaluation Number of bits that is succeeded to send Equivalent to ideal performance because no collision occurred even RAP only is used. Equivalent to ideal performance because G-Slot does not allocate useless slot RAP phase length and collision probability decrease Offered load vs. Throughput performance Submission Slide 32 Superframe consists only MAP. No collision occurred. Performance limit of proposal method is closer to ideal performance than conventional method. Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWCNippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep Simulation results ❖ Delay characteristics RAP has better performance of delay than conventional method Proposal method can achieve smaller delay than conventional method because most of parts of superframe are used as RAP. By changing MAP length, lowdelay character of RAP can be kept in this offered load condition. In this portion, MAP only is used. In this condition, delay characteristics has performance floor depends on the slot period. Offered load vs Delay performance Submission Slide 33 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWCNippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep Simulation results ❖ Guaranteed worst performance Even in condition that RAP is dominant, superframe provides suitable number of GSlot and guarantees worst performance. By using G-Slot, MAC layer can guarantee the worst case performance. In addition, worst performance is improved. Slot period determines the performance limit in all priority. Worst-case performance of proposal method. Submission Slide 34 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWCNippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep Conclusions ❖ Efficiency of Transmission Channel Utilization Meeting the requirements of downlink traffic, for which G-Slot and M-EAP were proposed, our scheme became the high channel utilization of transmission under half duplex transmission. ❖ Bi-directional Transmission we proposed adaptive frame design algorithm for WBAN. Considering the assignment of transmission slot in contention free, proposal scheme achieved the permissible value in both one and bi-directional models. ❖ Worst-case performance guarantee Based on the Extended G-Slot( Guaranteed slot) superframe structure, proposal scheme can be achieves better performance than the conventional method in worstcase. Proposal method can guarantee permitted delay and throughput performance even in worst case condition. Moreover, when the network condition was changed in the point of offered load, our scheme had the flexibility superframe management to network traffic and showed the better performance, throughput, latency, and transmission success rate, than current standard method. Submission Slide 35 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWCNippon)

July 2018 doc. : IEEE 802. 15 -18 -0115 -01 -0 dep References • Toshikuni Miyazaki, Tomohiro Fukuya, and Ryuji Kohno, “A MAC protocol with slot prediction algorithm for wireless body area network, ” 2017 11 th International Symposium on Medical Information and Communication Technology (ISMICT), Lisbon, Portugal, Feb. 2017. • Toshikuni Miyazaki, Tomohiro Fukuya, and Ryuji Kohno, “A MAC protocol based on priority control corresponding to Qo. S levels of each node and packet in WBAN, ” The symposium on Medical Information and Communication Technology(MICT 2016 -6), pp. 29 -33, Tokyo, Japan, May. 2016. (in Japanese) • Toshikuni Miyazaki, Kento Takabayashi, and Ryuji Kohno, “A MAC protocol considering bidirectional communication in wireless body are network, ” The 40 th Symposium on Information Theory and its Applications (SITA 2017), pp. 86 -90, Niigata, Japan, Nov. 2017. (in Japanese) • Toshikuni Miyazaki, Tomohiro Fukuya, and Ryuji Kohno, “A study for MAC protocol based on Qo. S levels under some scenarios in WBAN, ” 2016 IEICE Society Conference, no. B-20 -14, Hokkaido, Japan, Sept. 2016. (in Japanese) Submission Slide 36 Toshikuni Miyazaki(YNU), Ryuji Kohno(YNU/CWC-Nippon)