Multiple GHz of internationally available, unlicensed spectrum surrounding the 60 GHz carrier frequency has the ability to accommodate high-throughput wireless communications. While the size and availability of this free spectrum make it very attractive for wireless applications, 60 GHz implementations must overcome many challenges. For example, the high attenuation and directional nature of the 60 GHz wireless channel as well as limited gain amplifiers and excessive phase noise in 60 GHz transceivers are explicit implementation difficulties. The challenges associated with this channel motivate commercial deployment of short-range wireless local area networks, wireless personal area networks, and vehicular networks. In this paper we detail design tradeoffs for algorithms in the 60 GHz physical layer including modulation, equalization, and space-time processing. The discussion is enhanced by considering the limitations in circuit design, characteristics of the effective wireless channel (including antennas), and performance requirements to support current and next generation 60 GHz wireless communication applications.

60 GHz wireless communications: emerging requirements and design recommendations

This paper calculates the capacity of continuous phase modulation (CPM) schemes, modeling CPM as a finite state machine. The novel capacity-calculation algorithm gives a reliable estimate of the capacity using minimal computer time. This algorithm allows the production of a more generalized class of modulation schemes called generalized CPM, which have a higher capacity than traditional CPM schemes of comparable bandwidth

General CPM and its capacity

The thesis investigates Joint Source and Channel Coding 
(JSCC) using combined Trellis Coded Quantization (TCQ) and coded modulation. First we investigate a JSCC scheme using combined TCQ/Trellis Coded CPM (TCQ/TCCPM). Based on the BCJR algorithm for trellis coded CPM, we derive an optimal soft decoding algorithm for the considered systems. Analytical bounds on the channel distortion for jointly designed TCQ/TCCPM systems with maximum likelihood sequence detection are derived. These bounds are based on the transfer function technique, which has been modified and generalized to analog signals in discrete time for our purpose. 
This work provides an analysis tool to estimate the performance for a given combined TCQ/TCCPM system. The analysis method is very general, and may be applied to any trellis based JSCC scheme. Next, we develop an iterative decoding approach to JSCC using serially concatenated TCQ/CPM. This iterative procedure exploits the structure of the TCQ encoder and the continuous phase modulator. A new trellis quantization scheme based on punctured ring convolutional codes is also proposed. It is demonstrated that the new trellis source encoding scheme is superior to conventional Trellis Coded Vector Quantization (TCVQ) scheme of the same complexity. Furthermore, an adaptive JSCC scheme using the combined new trellis quantization scheme with CPM is investigated. 
The decoding algorithm is based on the BCJR algorithm for punctured ring convolutional coded CPM. An iterative decoding approach to the above mentioned adaptive JSCC scheme is also developed. The performance is analyzed by using the extrinsic information transfer chart.

Upper Bounds on the Channel Distortion of Joint Source-Channel Coding Using Trellis Coded CPM

A new trellis-based coded quantisation scheme using ring convolutional codes is presented When it is combined with trellis-coded continuous phase modulation (TCCPM) with convolutional codes over rings, a powerful joint source and channel coding (JSCC) scheme can be formed We investigate the additive white Gaussian noise (AWGN) channel and the Rayleigh fading channel Optimal soft decoding for the proposed JSCC scheme is studied The soft decoder is based on the a posteriori probability (APP) algorithm for TCCPM with ring convolutional codes It is shown that these systems with soft decoding outperform the
same systems with hard decoding especially when the systems operate at low to medium signal-to-noise ratio (SNR) It is demonstrated that the new trellis quantisation schemes based on ring convolutional codes is
superior to conventional trellis-coded quantisation (TCQ) of the same complexity The novelty of this work is in the development of a trellis-based quantisation method using ring convolutional codes and the use of a soft decoder and the APP algorithm for the combined systems

On combined ring convolutional coded quantisation and CPM for joint source/channel coding

The paper shows a procedure for evaluating the symmetric ergodic capacity of nonlinearly modulated finite alphabet signals in the MIMO random channel. We first investigate informationally an equivalent signal space representation for finite alphabet signals. The signals are allowed to be multidimensional per one antenna to reflect the modulation nonlinearity. The informationally equivalent signal space representation allows a factorization per one eigenmode (depending purely on one marginal eigenvalue) in the capacity evaluation in the MIMO channel. The evaluation complexity does not depend on the MIMO dimensions. We consider two types of channel signal constraints. (1) A constraint on the waveform only. (2) A constraint on the waveform and memory (modeled as a Markov chain). The mean symmetric capacity for the former one is derived. For the latter one, we derive lower and upper bounds based on the entropy rate approximation.

/pdf/symmetric-capacity-of-nonlinearly-modulated-finite-alphabet-11dbo6grah.pdf

Symmetric capacity of nonlinearly modulated finite alphabet signals in MIMO random channel with waveform and memory constraints

We derive upper bounds on the capacity of an additive Gaussian noise channel with continuous phase modulation (CPM). We propose an MMSE approximation to Laurent's (1986) linear decomposition using an arbitrary number of filtered, linearly modulated pulses. Using this linear modulation structure, we derive capacity bounds for both white and colored noise channels with CPM modulation by showing the system is equivalent to a multiple access channel (MAC) with intersymbol interference (ISI). The rate sum capacity of this cooperative MAC is used for the upper bound. Numerical results are presented for a channel using CPM with both white and colored noise. The bounds show a significant gap between a channel using CPM and a channel with unconstrained modulation.

K.C. Yu

Papers

Linear models and capacity bounds for continuous phase modulation