Device-to-Device Communication in Cellular Networks

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Device-to-Device Communication in Cellular NetworksSpeaker: Tsung-Han ChiangDate: Feb. 24, 2011

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PapersResource Sharing Optimization for Device-to-Device Communication Underlaying Cellular Networks

IEEE Transactions on Wireless Communication, Vol. 10, No. 8, August 2011

Resource Allocation Optimization for Device-to-Device Communication Underlaying Cellular Networks

IEEE 73rd Vehicular Technology Conference Spring 2011

Device-to-Device Communication in Cellular Networks Using Fractional Frequency Reuse

2011 17th Asia-Pacific Conference on Communications (APCC)

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IntroductionThere is an increasing requirement for local communication, such as games between mobile phones, video sharing, and information broadcast in hot spot area like market.The D2D communication reduces the transmit power of terminal, which increases the working time of terminal and improves the energy efficiency.The D2D communication can decrease the load of base station via direct transportation.The D2D communication has the advantage that licensed spectrum is allocated to local communication.

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IntroductionThe BS is capable of coordinating the interference between cellular communication and D2D communication by proper power control and resource allocation with the channel state information (CSI) of all involved links.In prior studies, one D2D pair reused the resource of only one cellular user whenever there was one or more cellular user in the system.In actual networks, cellular users are more than D2D pairs generally, so the spectrum is not used efficiently when one D2D pair reuses the resource of only one cellular user.

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The authors assume that the BS has the CSI of all involved links. The available resources are allocated to the cellular users and the D2D pair based on the CSI.

System Model

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System ModelThere are four resource allocation methods in D2D communication underlaying cellular networks.

Cellular mode Dedicated resource mode Reusing the resource of only one cellular user Reusing the resources of more than one cellular user

With reusing the same resources, the SINR of the cellular communication should be higher than , and the SINR of D2D communication should be higher than .An SINR higher than does not increase the sum throughput because of the restriction of the highest modulation and coding scheme (MCS).

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Resource Allocation Algorithm

By applying the Shannon capacity formula, the sum throughput of cellular communication and D2D communication of the four methods can be expressed as:

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Numerical Simulation

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IntroductionIn order to accommodate huge multimedia traffic, capacity of cellular networks should be enhanced by extending available frequency band or deploying new eNBs.In pre-existing cellular networks, eNB should relay UE’s data even though users located in same cell coverage communicate with each other.Pre-existing communication increases communication delay and offered load to eNB because of densely crowded user.

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IntroductionHowever, D2D UEs may generate high interference to eNB relaying UEs located in their communication areas if they use the same spectrum with the eNB relaying UEs for data transmission.

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PreliminariesPerformance of the cellular network, such as channel quality of UEs in cell outer region, is primarily affected by inter-cell interference (ICI).In frequency reuse factor (FRF) of one, since every cell uses same frequency band for data transmission, serious interference to UEs in cell outer region can be generated from neighboring cell. The simplest way to alleviate ICI is to use FRF greater than one. However, it may decrease spatial spectrum efficiency of the cellular network.

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PreliminariesInter-cell interference coordination (ICIC) can be classified into dynamic ICIC scheme and static ICIC scheme.

The dynamic ICIC scheme coordinates interference between adjacent cells by dynamically allocating radio resource and adjusting transmission power of eNB.

The static ICIC scheme such as fractional frequency reuse (FFR) statically determines the radio resources used for cell inner and cell outer regions to avoid interference between neighboring cells.

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Proposed Scheme

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Performance EvaluationThe authors consider a cellular network with 7 hexagonal cells.The number of eNB relaying UEs per cell is 70 and they are uniformly distributed.In each cell, 93 D2D senders are distributed in grid pattern with distance of 100 m, and D2D receivers are apart from their corresponding D2D senders with distance , where is uniform random variable in [20, 50] m.

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Performance Evaluation

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Performance Evaluation

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ConclusionMobility

Scalable

Interference between D2D links

Broadcast and multicast

Device-to-Device Communication in Cellular Networks

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