In this paper, we analyze the association of a user terminal in a two-tier network (i.e., macrocells and millimeter wave small cells). We assumed a decoupled wireless access where a user terminal has the liberty to choose different base stations (BSs) in uplink and downlink based on the received power and the channel quality. A practical blockage model where a human body is a blockage to millimeter wave (mmW) is considered. An in-depth simulation study is done to explore the effectiveness of decoupled wireless access in a crowded environment. In addition to that, a detailed analysis on the intuitiveness and the mathematical tractability of the blockage model used is also provided. In the end, few research questions on the efficacy of decoupled wireless access are raised in this paper.

In this paper we present a novel iterative error control technique which circumvents both the complexity and latency shortcomings of the usual turbo codes. It differs from usual turbo coding techniques as it uses a single encoder (hence with no interleaver at the encoding process) and a single decoder. The technique is based on a novel class of orthogonal threshold decodable codes called convolutional self doubly orthogonal codes (CSO/sup 2/C).

This paper describes a complete digital radio system model which takes into account the effects of most degradations due to channel conditions and equipment imperfections. System parameters which are taken into consideration include, but are not limited to, the following: modulator imbalance, filter frequency responses, power amplifier nonlinearities, carrier and symbol timing recovery loops, and synthesizer phase noise. The parameters for each module in the radio can be varied, and the end-to-end performance computed. Furthermore, a novel semianalytic method is developed for the purpose of speeding up the simulation leading to the calculation of the bit error rate (BER) versus E/sub b//N/sub o/ for the radio model. This novel technique, when compared with classical semianalytic methods, provides 1 dB improvement in the accuracy of the simulation results. The model accurately predicts the radio performance as measured by BER versus E/sub b//N/sub o/, dispersive fade margin, transmitted frequency spectrum, and transient acquisition responses. Simulation results for 16 QAM and OQPSK systems were compared to measurements on two physical radios. The accuracy of the simulation results was found to be within 0.1 dB in E/sub b//N/sub o/ at a BER of 10/sup -6/ without the RF portions and between 0.2 and 0.45 dB for a complete radio system.

New designs for soft-decision threshold decoders are developed to significantly reduce the complexity and increase the coding gain as compared to previously proposed architectures. The approximate a posteriori probability (AAPP) decoder considered here is a digital approximation of the a posteriori probability (APP) decoder introduced by Massey (1976). These designs are useful for high-rate self-orthogonal convolutional codes with a long constraint length. The study case considered in this paper is for a rate 23/24, constraint length 4056 code used in a typical microwave digital radio. The new decoder architecture provides a four-fold decrease in complexity and an additional 0.3 dB coding gain as compared to previous designs.>