NTT DoCoMo

About: NTT DoCoMo is a based out in . It is known for research contribution in the topics: Base station & Mobile station. The organization has 4032 authors who have published 8655 publications receiving 160533 citations.

Interference-aware resource allocation for device-to-device communications as an underlay using sequential second price auction

Abstract: An innovative resource allocation scheme is proposed to improve the performance of device-to-device (D2D) communications as an underlay in the downlink (DL) cellular networks. To optimize the system sum rate over the resource sharing of both D2D and cellular modes, we introduce a sequential second price auction as the allocation mechanism. In the auction, all the spectrum resources are considered as a set of resource units, which are auctioned off by groups of D2D pairs in sequence. We first formulate the value of each resource unit for each D2D pair, as a basis of the proposed auction. And then a detailed auction algorithm is explained using a N-ary tree. The equilibrium path of a sequential second price auction is obtained in the auction process, and the state value of the leaf node in the end of the path represents the final allocation. The simulation results show that the proposed auction algorithm leads to a good performance on the system sum rate, efficiency and fairness.

MIMO two-way relaying with transmit CSI at the relay

Abstract: Conventional half-duplex relaying schemes suffer from the loss in spectral efficiency due to the two channel uses required for the transmission from the source to the destination. Two-way relaying is an efficient means to reduce this loss in spectral efficiency by bidirectional simultaneous transmission of data between the two nodes. In this paper we study the impact of transmit channel state information at the relay in a MIMO two-way decode-and-forward relaying scheme. We investigate and compare two different re-encoding schemes at the relay. The first is based on superposition coding, whereas the second one is based on the bitwise XOR operation.

Menu item selecting device and method

Abstract: As menu items configuring a menu page displayed in a display device of a cellular phone, facial portraits of persons with whom a predetermined function is executed can be registered.

Breaking the memory secrecy assumption

Abstract: Many countermeasures exist that attempt to protect against buffer overflow attacks on applications written in C and C++. The most widely deployed countermeasures rely on artificially introducing randomness in the memory image of the application. StackGuard and similar systems, for instance, will insert a random value before the return address on the stack, and Address Space Layout Randomization (ASLR) will make the location of stack and/or heap less predictable for an attacker.A critical assumption in these probabilistic countermeasures is that attackers cannot read the contents of memory. In this paper we show that this assumption is not always justified. We identify a new class of vulnerabilities -- buffer overreads -- that occur in practice and that can be exploited to read parts of the memory contents of a process running a vulnerable application. We describe in detail how to exploit an application protected by both ASLR and stack canaries, if the application contains both a buffer overread and a buffer overflow vulnerability.We also provide a detailed discussion of how this vulnerability affects other, less widely deployed probabilistic countermeasures such as memory obfuscation and instruction set randomization.

Capacity and Fairness Analysis of Heterogeneous Networks with Range Expansion and Interference Coordination

Abstract: Range expansion and inter-cell interference coordination (ICIC) can improve the capacity and fairness of heterogeneous network (HetNet) deployments by off-loading macrocell users to low-power nodes. Due to difficulties in analytical treatment, current studies for range expansion and ICIC in HetNets rely mostly on simulations. In this letter, first, off-loading benefits of range expansion in HetNets are captured through cumulative distribution functions (CDFs) of the downlink signal to interference plus noise ratio (SINR) difference between the macrocell and strongest picocell signals. Then, these CDFs are used to investigate the system capacity and fairness as a continuous function of the range expansion bias, and benefits of using ICIC with range expansion are demonstrated through numerical results.