Shu (Marloon) Wang

There are many parameters or specifications defined for quantifying the performance of a receiver design and implementation. Among them, the most notable includes the reference sensitivity power level (REFSENS) and the Total Isotropic Sensitivity (TIS), which are widely used for specify how sensitivity a receiver is. More sensitive a receiver is, less power it requires for maintaining a reliable communication and better performance it is believed to have. In general, REFSENS measures the performance of the receiver module with considering its down-converting performance, demodulation/decoding capability and self-generated interference/noise. Per 3GPP definition, REFSENS specifically denotes the minimum mean power applied to each applicable receive antenna port at which the throughput shall meet or exceed the requirements, which is not less than 95% of the maximum throughput of the specified reference measurement channel. See §7.3, Annexes A.2.2 (for FDD), A.2.3 (for TDD) and ...

Interference Cancellation: A Short Overview How to Broadcast Multimedia Contents? [Note] Due to the asymmetry between the uplinks and downlinks of a mobile network, there are different considerations, tradeoffs and techniques for designing each directions. In general, with the recent advance on uplink interference cancellation and management techniques, mobile network is usually limited by downlinks due inter-cell interference, especially when delay is a key part of the equation. On this blog, my focus will be on downlinks. How to evolve mobile system uplinks will be discussed in separated blogs. Mobile system design usually starts from our understanding of wireless channels and the services customers are demanding. The properties of various wireless channels can help us understand the system design limitation we are facing and the potentials we may achieve.  For example, COST 231 model, which was developed by European COST Action 231. Its variations are the most popular...

Evolving Random Access Channel What Is The Next for Mobile System Design? How Much Feedback Is Enough for MIMO? How to Broadcast Multimedia Contents? Interference Cancellation: A Short Overview Location Based Services for Mobiles From Chair's notes, there are more than 40 work or study items proposed for enhancing LTE Advanced or  both LTE-Advanced and HSPA. They will be completed by September 2012. Further Enhanced Non CA-based ICIC for LTE LTE Carrier Aggregation Enhancements Study on Coordinated Multi-Point Operation for LTE Study on Enhanced Uplink Transmission for LTE Study on further Downlink MIMO enhancements for LTE-Advanced Study on Further Enhancements to LTE TDD for DL-UL Interference Management and Traffic Adaptation Coordinated Multi-Point Operation for LTE Provision of low-cost MTC UEs based on LTE Proposed SI on LTE Coverage Enhancements Improvements to LTE Relay Backhaul Study on LTE Device to Device Discovery and Communication - Radio Aspects N...

One key feature of any mobile communication system is to provide a mobility mechanism for mobiles to do fast and seamless switching between serving cells. There are many different handover mechanisms for achieving this goal. They include soft handover, which is mostly used for voice services, and hard handover, which is designed for data services. Hard handovers can be further classified as network-controlled handovers and mobile-based handovers. The interesting thing is if you look at the basic handover or handoff procedures I will explain in the next, you may feel a long-time debate on which entity , base stations or mobiles, should control handover or handoff. Traditionally there is no standardized direct connection between two BTS's, even they both belong to the same BSC. Therefore, there usually are a long outage for a mobile do hard handover. For example, the default forward traffic channel MAC handover scheme of CDMA2000 EV-DO Rev. 0 usually results in 100~200ms ou...

One advanced feature of 3GPP LTE-Advanced is carrier aggregation. It is an essential mechanism for LTE Release 10/11 to meet the peak-data rate, 1Gbps, requirement of IMT-Advanced of ITU-R. Beside this, it also helps LTE maintain backward compatibility, support symmetric/asymmetric operation modes and contiguous/non-contiguous aggregations. All these features help enable a variety of network deployment scenarios, such as hot-spot operations and flexible duplex. Historically carrier aggregation is not something brand-new in standards.  On 3GPP2 side, the IS-2000 standard supports a multi-carrier operation, Spreading Rate 3 or 3x. Spreading 3 is used when higher data rates are desired with more bandwidth available. Spreading 3 of multi-carrier operation can make IS-2000 not only is backward compatible with its IS-95 predecessor but also satisfies the requirements set forth by IMT-2000/3G at that time. With adding additional guard band, IS-2000 can...