Device Cooperation for M2M Communications IEEE Presentation Submission Template (Rev. 9) Document Number: IEEE C802.16p-10/0004r1 Date Submitted: Source: Kyujin Park, HanGyu Cho, Jin Lee, Kiseon Ryu, JinSam Kwak {kyujin.park, LG Electronics Re:Project Planning Committee's Session #69 WG Closing Plenary Report (IEEE ppc-10/0014) Venue: IEEE Session #70 Base Contribution: IEEE ppc-10/0011r2 Purpose: To be discussed and adopted by TGp. Notice: This document does not represent the agreed views of the IEEE Working Group or any of its subgroups. It represents only the views of the participants listed in the Source(s) field above. It is offered as a basis for discussion. It is not binding on the contributor(s), who reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEEs name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEEs sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE Patent Policy: The contributor is familiar with the IEEE-SA Patent Policy and Procedures: and. Further information is located at and.

Preliminaries - What is device cooperation? Device cooperation is a technique to exploit D2D(Device-to-Device) link in addition to the existing WWAN link for the following benefits. Capacity enhancement Reduction of power consumption Related terminologies Source device: The end device whom the data traffic to the BS is generated from or the data traffic generated from the BS is targeting for Cooperative device: The device who helps the source device(s) in UL or the BS in DL by relaying or co-transmitting data and control information Network lifetime: Duration of time until the first node (device) failure due to battery depletion WWAN BS WWAN link WWAN link (e.g m) D2D link

Preliminaries - Device cooperation modes Mobile relaying A cooperative device performs the functionality of a RS(Relay Station). A cooperative device forwards the data of a source device to the BS. For example, the source device send data traffic to the cooperative device through D2D link at T1, and the cooperative device send it to the BS at T2 as shown in Fig. 1. Additionally, a concept of group anchor where an anchor device collects data traffic from multiple source devices and forwards it to the BS, can be another example of mobile relaying. Cooperative transmission Both of a cooperative device and a source device transmit data traffic of a source device to the BS. In this mode, the data traffic of the source device is shared with the cooperative device through the D2D link transmission in advance, and then the shared data traffic is transmitted to the BS from the source and cooperative device jointly. For example, the source device send data to the cooperative device at T1, and both of the source and cooperative devices transmit the data to the BS simultaneously at T2 as shown in Fig. 2. BS Cooperative device Source device T1 T2T2 Fig. 1. Mobile relaying (a) Mobile relaying(b) Group anchor BS Source device Cooperative device T1 T2T2 T2T2 Fig. 2. Cooperative transmission

Motivation IEEE p PAR scope This amendment specifies IEEE Std medium access control (MAC) enhancements and minimal orthogonal frequency division multiple access (OFDMA) Physical Layer (PHY) modifications in licensed bands to support lower power consumption at the device, support by the base station of significantly larger numbers of devices, efficient support for small burst transmissions, and improved device authentication. For and, device cooperation is promising for M2M from the perspective of M2M requirements Low power consumption at the device Cost-effective M2M device M2M features Low or no mobility Time tolerant data transmission Infrequent small data transmission M2M applications Smart Grid Sensors (e.g. disaster, climate, flood, trash can, etc.) More specifically, Mobile relaying can be beneficial for Group anchor can be beneficial for and

Motivation In this contribution, we assume that Device cooperation among M2M devices is considered only for fixed M2M devices(i.e. M2M devices with no mobility). The application scenario of device cooperation is mainly focused on UL case to reduce M2M device transmit power consumption. The necessity of device cooperation for DL case is FFS.

Advantages of M2M Device Cooperation To increase network lifetime by resolving unbalanced power consumption among fixed M2M devices For fixed M2M devices, the energy consumption and relevant battery lifetime of each M2M device will be different depending on the geometry of the devices even if the M2M devices are same type of devices (with same battery equipped) which are deployed by a same user(or service provider) because of the difference of path-loss and relevant Tx power required. The energy required for UL transmission of given data traffic will be much higher for cell-edge M2M devices than near-cell M2M devices and the battery of cell-edge M2M devices will be depleted much faster. Therefore, the battery of cell-edge M2M devices needs to be replaced much frequently comparing with the near-cell M2M devices and it can be undesirable for M2M users(services providers). IEEE p BS Near-cell M2M device Cell-edge M2M device L1 L2 L1 << L2 L1 : pathloss between near-cell M2M device and BS L2: pathloss between cell-edge M2M device and BS

Advantages of M2M Device Cooperation To increase network lifetime by resolving unbalanced power consumption among fixed M2M devices (contd) Device cooperation can be a candidate solution for this power unbalancing among fixed M2M devices deployed by a same user(service provider) as shown in the following figure. 7 IEEE p BS Near-cell M2M device Cell-edge M2M device L1 L2 L3 L1, L3 << L2 L1 : pathloss between near-cell M2M device and BS L2: pathloss between cell-edge M2M device and BS L3: pathloss between near-cell and cell-edge M2M devices

Advantages of M2M Device Cooperation Battery lifetime extension for battery-limited M2M devices Device cooperation can be also exploited for battery lifetime extension for battery limited M2M devices. As an example, a nearby M2M device with power source can relay the UL transmission of battery-limited M2M device which result in path-loss gain and reduced power consumption for UL transmission for the battery-limited M2M device. A group anchor device which may have a power source can also gather the data traffics of nearby battery limited M2M devices and forward them to the BS. 8 IEEE p BS M2M device with power source Battery-limited M2M device X

Advantages of M2M Device Cooperation Support of larger number of M2M devices Group anchor can enable efficient group control and data transmission of multiple M2M devices Efficient power usage from device perspective Device cooperation using multi-RAT would require more power consumption on the source and cooperative devices than the single-RAT device cooperation because of the multi-RAT operation. Moreover, IEEE WLAN is based on the contention based multiple access scheme which is not so power-efficient. Therefore, single-RAT device cooperation will be more appropriate for the purpose of reducing device power consumption efficiently. Cost effectiveness from device perspective A device supporting single-RAT device cooperation does not require multi-RAT modems.

Proposed Text on IEEE ppc-10/0011r2 [Insert the following text in Section 3 of IEEE ppc-10/0011r2 ] -Device collaboration: A technique where a certain device helps the other devices transmission [Insert the following text in Section 6.1 of IEEE ppc-10/0011r2 ] The p system shall support device collaboration without defining a new 16p pier-to-pier connection [Replace fig. (a) in Section 5.4 of IEEE ppc-10/0011r2 with the following figure] p M2M Reference System Architecture