Ryusuke Matsukawa

A Dynamic Channel Assignment Scheme for Distributed Antenna Networks

In this paper, we propose a dynamic channel assignment (DCA) scheme for distributed antenna networks (DANs). DANs, in which many antennas are distributed in each cell, significantly reduce the transmit power compared to conventional cellular networks (CNs). In DAN, a different group of channels should be assigned for each distributed antenna to avoid the interference. Since DAN can also reduce the interference power due to its low transmit power property, the same channel groups can be reused even within the same cell. Proposed DCA scheme dynamically assigns the channels based on the co-channel interference measurement. Computer simulation results demonstrate that the DAN using proposed DCA achieves higher spectrum efficiency than the conventional CN.

Recent advances in single-carrier distributed antenna network

For the realization of future wireless networks, gigabit wireless technology, which can achieve higher-than-1 Gbps data transmission with extremely low transmit power, is indispensable. We have been studying the distributed antenna network (DAN) and the frequency domain wireless signal processing. In DAN, many antennas or clusters of antennas are spatially distributed over a service area, and they are connected by means of optical fiber links with DAN signal processing center. A number of distributed antennas cooperatively serve mobile users using spatial multiplexing, diversity, array, or relaying technique. In this paper, the recent advances in single-carrier DAN are introduced. Copyright

Downlink Throughput Performance of Distributed Antenna Network Using Transmit/Receive Diversity

In this paper, we investigate how a distributed antenna network (DAN) offers better throughput performance than a conventional cellular network (CN). In DAN, a group of multiple antennas are distributed in each cell of the CN in order to mitigate the adverse effect of path loss. Moreover, antenna diversity technique can make use of shadowing and multipath fading to improve the transmission performance due to a large spatial diversity gain. In this paper, we consider frequency-domain space-time block coded-joint transmit/ receive diversity (FD-STBC-JTRD) for downlink transmission of single-carrier (SC) DAN. FD-STBC-JTRD uses frequency-domain pre-equalization (pre-FDE) instead of receive FDE to keep the mobile terminals complexity low, and achieves the full-diversity gain. We show by computer simulation that the transmit power for achieving the required throughput can be significantly reduced compared to the conventional CN.

Single-carrier distributed antenna network downlink using joint transmit/receive diversity

Single-carrier distributed antenna network (SC-DAN), in which a group of multiple antennas are distributed in a cell serve a user, can mitigate adverse impacts of path loss, shadowing loss and multipath fading. Frequency-domain space-time block coded-joint transmit/ receive diversity (FD-STBC-JTRD) is attractive for downlink transmission since an arbitrary number of distributed transmit antennas can be used. FD-STBC-JTRD requires the channel state information (CSI) only at the transmitter side and therefore, the complexity problem of mobile terminals can be alleviated. In this paper, we investigate, by computer simulation, the bit error rate (BER) distribution of the SC-DAN downlink. We discuss the impact of the number of distributed antennas involved in FD-STBC-JTRD on the BER outage probability.

Spectral Efficiency of Distributed Antenna Network Using MIMO Spatial Multiplexing

Multiple-input multiple-output (MIMO) spatial multiplexing is known to increase the transmission rate without bandwidth expansion. However, in cellular networks (CNs), the transmission rate of a user close to the cell edge significantly degrades because the received signal-to-interference plus noise power ratio (SINR) degrades due to the presence of strong co-channel interference (CCI) from neighboring cells. Distributed antenna network (DAN), in which many antennas are spatially distributed over the cell, is suitable for MIMO spatial multiplexing because the received SINR improves over the entire cell. In this paper, assuming block transmission with cyclic prefix (CP) insertion, we theoretically derive an expression for the downlink spectral efficiency of DAN-MIMO spatial multiplexing in a multi-cell environment. Then, we propose the optimal and suboptimal transmit power allocation schemes for DAN-MIMO spatial multiplexing. We evaluate the spectral efficiency distribution by Monte Carlo numerical computation method to show that DAN allows single frequency reuse and achieves higher spectral efficiency compared to CN.

Channel capacity of distributed antenna network using spacetime block coded-joint transmit/receive diversity

Distributed antenna network (DAN) is a promising wireless network to solve the problems arising from shadowing and path lesses as well as frequency-selective fading. Many anntennas are spatially distributed around each base station (BS) so that with a high probability, some antennas can always be visible from a mobile station (MS). Recently, we proposed a 2-dimensional water-filling (2D-WF) transmit diversity for single-carrier (SC) DAN downlink transmission. An MS having single receive antenna was considered. In this paper, we extend the 2D-WF transmit diversity to the case of MS having multiple receive antennas to implement frequency-domain space-time block coded-joint transmit/receive diversity (FD-STBC-JTRD). The channel capacity distribution is evaluated by Monte-Carlo numerical computation method. It is shown that the use of 2 receive antennas maximize the downlink channel capacity while the use of around 5 distributed transmit antennas is sufficient.

Gigabit distributed antenna network and its related wireless techniques

For the realization of future wireless networks, gigabit wireless technology which can achieve higher-than-1Gbps data transmission with extremely low transmit power is indispensable. We have been studying the distributed antenna network (DAN) and the frequency-domain wireless signal processing. In DAN, many antennas or clusters of antennas are spatially distributed over a service area and they are connected by means of optical fiber links with DAN signal processing center (SPC). A number of distributed antennas cooperatively serve mobile users using spatial multiplexing, diversity, array or relaying technique. In this paper, the recent research advances of gigabit DAN and its related wireless techniques are introduced.