As microcell wireless systems become more widespread, intercell interference among the access points will increase due to the limited frequency resource. In the overlapping cell scenario, radio resources should be shared by multiple cells. Although time and frequency resource sharing has been described in many papers, there is no detailed report on dynamic spatial resource sharing among multiple cells for microcell wireless systems. Thus, we present the effectiveness of spatial resource sharing among two access points. We introduce two scenarios based on the zero forcing method; one is the primary-secondary AP scenario and the other is the cooperative AP scenario. To evaluate the transmission performance of spatial resource sharing, channel matrices are measured in an indoor environment. The simulation results using the measured channel matrices show the potential of spatial resource sharing. 1. Introduction The rapid increase in data traffic has led to strong demands for large-capacity transmission systems. Wireless local area networks (WLAN) and cellular systems are two major wireless access systems that are being targeted to achieve even higher data rates. Orthogonal frequency division multiplexing (OFDM) and multiple input multiple output (MIMO) have been recognized as effective ways to attain higher throughput for IEEE 802.11n [1] and 3G Long term evolution (LTE) [2]. Unfortunately, the recent advances in these techniques still lag the demands being made, so bandwidth of each carrier is being increased from one generation to the next [1, 2]. Another trend in wireless access systems is the rapid increase in the number of wireless devices. The total number of cellular phone subscribers reached 100 million at the end of December in 2007 in Japan and exceeded the number of land phone subscribers [3]. The number of WLAN chip shipments in each year is also increasing and it reached to 200 million in 2008 [4]. It is thought that people will start putting wireless devices on machines in the near future. This changes the usage of wireless access from people to people (P-to-P) or people to machine (P-to-M) communication to machine to machine (M-to-M) communication and a huge growth in this market can be anticipated [1, 2]. The above trends bring new challenges for wireless technologies because both the larger bandwidth and the larger number of wireless devices may cause significant shortages in the frequency channels. One example is the ongoing standardization for very high throughput (VHT) wireless LANs in bands below 6？GHz, that is, IEEE802.11ac, which is
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