Shu (Marloon) Wang

Access Channel Enhancements for 1x Rel. F One Eighth Rate Access Probes for Smart Terminals Evolving Random Access Channel for IoT: III Slotted ALOHA Models Evolving Random Access Channel for IoT: IV Dumb Access Probes and Smart Access Probes Random access channel (RACH) is an contention-based uplink common channel resource, which is shared by multiple access terminals. The typical application scenarios, which trigger random access procedure, include initialize access from power up or radio link failure, initialize access from idle state, initialize access to the handover target, initialize access when uplink synchronization is unavailable. In addition, it can also be used by a terminal for registration update, location update and to send a small amount of data on the uplink. A key feature of random access channel is that messages are not scheduled and there is no certainty of collisions. This is different to a dedicated channel, which is  exclusively assigned to one u

Macro-diversity typically means a special communication mode between a single mobile station and multiple base stations in a cellular network. It has been in CDMA standards as soft handoff since the beginning. The people in the industry usually think "soft handoff" and "macro-diversity" are interchangeable in most scenarios. Recently it has been employed for CDMA2000 BCMCS and UMTS MBS too. The basic idea is to coordinate multiple base stations to deliver the same data stream to a mobile receiver in the down links and receive the signals from a mobile station from multiple base stations. Macro-diversity is possible for CDMA soft handoff because there is no hybrid automatic repeat request (HARQ) for voice data and no fast retransmission is necessary due to the strict delay requirement of voice service. The benefits of doing soft handoff on voice service include reduced transmission power and seamless mobility. On the other hand, it also challenges the mobile station