I-Kang Fu, Paul Cheng, MediaTek IEEE 802.21 MEDIA INDEPENDENT HANDOVER DCN: 21-10-0105-01-hwnm Title: Multi-Radio Integration for Heterog. Networks Date Submitted: May 13, 2010 Presented to Heterogeneous Wireless Networks Mgmt. SG at IEEE 802.21 session #38 in Bangalore Authors or Source(s): I-Kang Fu, Paul Cheng, MediaTek Abstract: Identify some issues in heterogeneous networks from a device-vendor perspective

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Introduction Huge demand on broadband wireless access will be stimulated in 4G era ~1Gbps peak transmission rate in wireless network can provide users similar experience as in wireline network Peak transmission rate should be no longer a critical problem after 4G era Most of the existing Internet services can be carried by 4G wireless networks Mobile Internet becomes reality and further stimulate more advanced services and substantially change the human life again The network capacity will soon be exhausted in next few years The spectral efficiency is improved less than ×10, but the capacity demand is increased more than ×100. 4G deployment will not slow down but most likely to speed up the happen of this problem by stimulating many novel broadband services Capacity exhaustion will be the most severe problem during the 4G and Beyond (B4G) era

Introduction The most efficient solution is to increase spectrum allocation The gain from spectral efficiency improvement becomes more and more marginal (e.g. increase MIMO order) additional spectrum for the same system can certainly help The required technology (i.e. multi-carrier) is already available in 4G systems (i.e. WiMAX 2.0 and LTE-Advanced) More spectrum from different systems will also be helpful New technology is required to achieve this objective in B4G era Heterogeneous network integration is the most promising candidate Average spectrum utilization in each country is poor today Different operators and different systems cannot share their spectrum resources The base station or access point distribution is different by each operator and system Traffic access demand by user is random in time and in location, but the network coverage by specific operator or system may not always be best available. But the spectrum resource by some other operator or network may be idle at the same time and the same location New technology is desirable to enable intelligent radio resource sharing

Problem Discussion Multiple radio access networks between information source and user May be operated by the same air-interface (e.g. different operators) Single tier network → can be resolved by existing roaming solution May be operated by different air-interfaces Heterogeneous network → new technologies are required to enable radio resource sharing

Problem Discussion Two design perspective need to be considered when discussing heterogeneous network issues: Network Integration Multi-Radio Integration Technology evolution may be categorized into three stages: (example) Coexistence Interference mitigation Cooperation Smart Internetworking Cognition Internetwork radio resource sharing

Multi-Radio Integration Challenges Challenges to support heterogeneous network from device perspective Stage 1: Interference mitigation for co-located multi-radio coexistence Objective – mitigate the interference from co-located modem to improve modem performances FDM based solution (i.e. filtering) may not work when the frequency channels are too close (e.g. between ISM band and 2.3GHz band) Protocol based solution may be required under some scenario Ongoing efforts in many different standard organizations BB: Baseband module RF: Radio Frequency module ANT: Antenna module

Multi-Radio Integration Challenges Challenges to support heterogeneous network from device perspective Stage 2: Smart interworking for co-located multi-radio component sharing Objective – efficient internetworking to help device maintain connections in multiple systems by shared hardware (e.g. RF module) For example, new protocol to help device fast switching between two system without losing control signals. Logical connection may still be maintained in parallel for service continuity

Multi-Radio Integration Challenges Challenges to support heterogeneous network from device perspective Stage 3: Intelligent spectrum sharing for cognition by fully integrated radio Objective – optimize the radio (spectrum) resources among multi-tier heterogeneous network by minimizing the duplicated hardware functions (FFS) Prevent unnecessary waste on spectrum resource, transmit power and processing power.

Summary Heterogeneous Network is the most promising technology which can significantly resolve the capacity exhaustion problem in Beyond 4G era New technology need to be developed both from network and device perspectives Possible parameters exchange to facilitate physical layer and RF switching Center frequency Frame timing PHY specific parameters (e.g. signal bandwidth) Possible parameters exchange to facilitate MAC connection setup Protocol version Security context MAC specific parameters (e.g. sleep/idle mode related parameters)