Convergence of wireless communications, computing and Internet is on the way. This will be the driving force towards a wireless multimedia society. In this paper, we will overview today's standards of 3G cellular and wireless LAN systems. There are two trends complementing each other: enhancing the cellular technology (3G WCDMA, cdma2000, etc) and enhancing the wireless LAN technology (HiperLAN, IEEE802.11, HiSWAN, etc). More or less, these two technologies have been evolving independently, but now, coordination between these two have been considered viable to realize broadband communication era. Recently, discussions on 4th generation (4G) wireless systems have been intensified. We will foresee how wireless systems will evolve into global 4G wireless systems. In global 4G wireless, cellular and wireless LAN systems architectures may become closer and will work together via IP core network. Difference between them may be that the former offers seamless handoff for real-time services but the latter offers seamless roaming for nomadic services, focusing on very high-speed data communications close to 1Gbps.