Implementation of Wireless Receiver Algorithms

Implementation of Wireless Receiver Algorithms Figure 1 System Specifications (Tsimenidis, 2016) Figure 2 Message format (Tsimenidis, 2016) Figure 3 Non-coherent receiver (Tsimenidis, 2016) Figure 4 Coherent receiver (Tsimenidis, 2016) Figure 5 Receiver Front-End (Tsimenidis, 2016) Figure 6 Frequency response of a passband filter (Tsimenidis, 2016) Figure 7 Band-pass filter response Figure 8 Band-pass filter input/output Figure 9 Implemented DPSK demodulator (Tsimenidis, 2016) Figure 10 Low-pass filter input/output Figure 11 Optima sample time diagram Figure 12 Symbol with 40 samples (Tsimenidis, 2016) Figure 13 Early-Late sample at an arbitrary point (Tsimenidis, 2016) Figure 14 Early-Late sample at the maximum point of power (Tsimenidis, 2016) Figure 15 Early-Late symbol synchronization input/output Figure 16 Result of non-coherent receiver detection Figure 17 IQ Downconverter (Tsimenidis, 2016) Figure 18 Sine and cosine table graphs Figure 19 Index control flow (Tsimenidis, 2016) Figure 20 Filter comparison (Tsimenidis, 2016) Figure 21 Down-conversion: x3I vs. x3Q counter clockwise Figure 22 Down-conversion: x4I vs. x4Q counter clockwise Figure 23 x6I vs. x6Q Figure 24 Averaging approach to overcome the jitter (Tsimenidis, 2016) Figure 25 Code to solve the jitter Figure 26 Principle of the differential detector (Tsimenidis, 2016) Figure 27 Constellation without Phase Offset (dI Vs dQ) Figure 28 Result of coherent receiver detection using differential coherent demodulator Figure 29 BPSK and DPSK BER comparison (Tsimenidis, 2016) Figure 30 Costas Loop algorithm (Tsimenidis, 2016) Figure 31 Costas loop: yQ vs. yI Figure 32 Message obtained using Costas loop Figure 33 BER comparison of different modulation schemes and techniques (Sklar, 1983) This project is focused on implementing and coupling several functional blocks that will allow us to detect, extract and decode a wireless message that is being broadcasted in the Merz lab of computers. In the following sections, we will find the implementations of coherent and non-coherent receivers. In the section 1 we define the basic background knowledge that will be commonly used in the posterior phases of the report. We define the basic structure and features of the transmitter as well as the message format that the system is intended to detect. Finally, we define what is a coherent and a non-coherent system and provide a classification about the different techniques. In the section 2 we will analyse the non-coherent receiver implementation from the message acquisition, going to the filter section, signal scaling and refinement, using a DPSK demodulator to define the probable symbols represented, then establishing a synchronization for the symbol and finally presenting the message obtained. The section 3 will focus in the realization of a coherent receiver, considering two possible variations on this type of implementation: the first will be developed using a differential coherent demodulator, in this technique we will not recover the carrier signal. The second implementation of this receiver, will be done using a carrier recovery technique, which is in this case a Costas Loop Algorithm. Some common blocks are done in all the possible implementations that were carried out during this project: the first is the receiver front-end which is the responsible to acquire and prepare the signal for the posterior processing. To recover the symbol synchronization, we use a technique called early-late gate, this will let us know what is the most convenient instant of the time to sample the signal. For the case of coherent signal, we must adapt this technique to apply it separately for the signal I (in-phase) and Q (quadrature). The section 4 contains analysis, conclusions and discussions of the results obtained during the realization of the phases. The last sections of the report detail the references used for further explanations and the different programs used for implementing each block. In each section, we include little further explanations that could be referred to understand the steps and details that have been done in the corresponding section. 1. Background knowledge 1.1. Aims and objectives The focus of this project is to demonstrate the implementation and the behaviour of data links using Radio Frequency as media and different techniques. Basically, we use two techniques: coherent and non-coherent implementations. A further explanation of these techniques will be done in the following sections. A second implementation of a coherent receiver will be carried out by using a phase recovery technique with the Costas Loop and coupling the posterior phase to this block. The specifications of the system to be implemented could be defined as a set of blocks connected as follows: Figure 1 System Specifications (Tsimenidis, 2016) Where the transmitter has been already implemented, therefore the work will be carried out in the receiver algorithm to obtain the final data, which of course must be in a human readable format. We also must consider that the format of the message that is being broadcasted wirelessly in the Merz lab has the following format: Figure 2 Message format (Tsimenidis, 2016) 1.2. Digital modulation The digital modulation process refers to a technique in which the digital representation of the information is embedded in a signal, a carrier typically a sinusoidal signal, in such a way that this information will modify an established parameter of the signal. We can define a sinusoidal carrier in a general way as a signal that will correspond to the equation: Where the information could be embedded in this will be called amplitude modulation, if the parameter this will be called frequency modulation and finally the phase modulation will be obtained if we embed the data in the expression. Regard to the symbol this is called the angular frequency, it is measured in radians per second, this is related to the frequency (f) expressed in Hertz by the expression. 1.3. Coherent and non-coherent detection Considering the receiver side, we can classify the demodulation or detection based on the use of the carriers phase information in the process of information recovery. In the case that the receiver uses this information to detect the signals it will be called coherent detection, and non-coherent detection otherwise. This are also called synchronous and asynchronous detection, respectively. Coherent Non-Coherent Phase Shift Keying (PSK) Diferential Phase Shift Keying (DPSK) Frecuency Shift Keying (FSK) Frecuency Shift Keying (FSK) Amplitude Shift Keying (ASK) Amplitude Shift Keying (ASK) Continuous Phase Modulation (CPM) Continuous Phase Modulation (CPM) Figure 3 Non-coherent receiver (Tsimenidis, 2016) Figure 4 Coherent receiver (Tsimenidis, 2016) 2. Non-coherent receiver 2.1. Receiver Front-End This segment of the non-coherent receiver will consist of the first two blocks, which are common for both coherent and non-coherent implementations. Figure 5 Receiver Front-End (Tsimenidis, 2016) The first block is the responsible to take a sampled input expressed as bits, represent it as a float number and then normalise it to a range +/- 1.0. The second stage applies a bandpass filter to the signal, this will attenuate the parasites components of frequency that could contaminate the signal that we received. Figure 6 Frequency response of a passband filter (Tsimenidis, 2016) To design the passband filter we must consider the following information: let = 4800 Hz, data rate = 2400 bps and sampling frequency = 48000 Hz. These assumptions, led us to the following results: Lower passband cut-off frequency: = = 3600 Hz Upper passband cut-off frequency: = + = 6000 Hz Lower stopband cut-off frequency: = = 1200 Hz Upper stopband cut-off frequency: = + = 8400 Hz The implementation of the filter will be done using the sptool command of Matlab, using the above defined values as parameters for the filter. The following figure shows the result obtained in the realization of the lab, considering the number of filter coefficients of 101. Figure 7 Band-pass filter response Figure 8 Band-pass filter input/output 2.2. DPSK demodulator To implement the non-coherent detection, we are going to use a DPSK demodulator, which was previously categorized as a non-coherent technique. The DPSK demodulator will take advantage of two basic operation that occur on the transmitter: the first is the differential encoding, and the second is the phase-shift keying. In the transmitter, the signal will be advanced in phase, with respect to the current signal, if the symbol to be sent is 0, and the phase will be preserved if the bit corresponds to 1. In the side of the receiver, we have memory that will be able to compare the phase of two successive bit intervals, i.e. it determines the relative difference in phase of these two, determining the correspondent symbols without the need of having information about the phase of the signal in the transmitter. Figure 9 Implemented DPSK demodulator (Tsimenidis, 2016) The FIR matched filter block will correspond to a low-pass filter, this is required because the demodulation process, as it is a multiplication between two sinusoidal signals, will generate a low-band signal and a high-band signal, where the second one should be filtered. 2.3. Symbol synchronisation The symbol synchronisation, also called symbol timing, is a critical process that consists in the continuous estimation and update of information of the symbol related to its data transition epochs. This is a critical process that must be conducted to keep the communication accuracy in acceptable levels. Broadly speaking, the synchronization techniques could be classified in two groups: open-loop and closed-loop. The chosen technique for this project corresponds to the Early-Late Symbol Synchronization which is a closed-loop type. The most popular technique is the closed-loop synchronization because Open-loop synchronizer has an unavoidable nonzero average tracking error (though small for large SNR, it cannot be made zero), a closed-loop symbol synchronizer circumvents this problem.(Nguyen Shwedyk, 2009) The corresponding results of the output of the demodulator are the following figures, these corresponds to the signals before and after the signal is filtered with the FIR low-pass filter. Notes: The curve in blue corresponds to the signal containing the high-frequency parasite component, and the curve in red shows the result of filtering the high frequency component, i.e. this is the output signal of the filter. The symbol correspondence is: symbol 0 for positive numbers, and symbol 1 for negative magnitudes. Figure 10 Low-pass filter input/output 2.3.1. Early-late Symbol Synchronization (Reed, 2002) The algorithm Early-late used for synchronization is supported by the idea that the sample of a symbol must be taken in the time where the energy is maximum, this will warranty a minimum error probability. This algorithm exploits the symmetry of the signal, neglecting the distortion and noise. Considering the following figure, we can see that the optimal time to take the sample, identified as T, should be in the halfway between two points T0 + d and T0 d, if the power in the T0 + d and T0 d is, ideally, the same. Figure 11 Optima sample time diagram Suppose the following figure shows a symbol, we can notice that if we take an arbitrary sample, e.g. n=3 and depending on the thresholds, could be wrongly interpreted as 0, however the most appropriated value is 1. Figure 12 Symbol with 40 samples (Tsimenidis, 2016) With a buffer size of 20 registers, we can notice that in the following figure the power levels of the signal for n=0 and n=19 are different, then we need to move the whole buffer one space to the right. Figure 13 Early-Late sample at an arbitrary point (Tsimenidis, 2016) If we continue with the iteration and we follow the rules described in the flow diagram, we will converge in a finite number of iterations, where we can see that the result is located as expected, this could be seen in the following figure. Figure 14 Early-Late sample at the maximum point of power (Tsimenidis, 2016) The results of the application of this algorithm for our case are shown in the following figure: Note: The signal in red is the input of the early-late symbol synchronization block and the signal in blue is the value of Em that will finally determine the value that the symbol is representing, in each case. Figure 15 Early-Late symbol synchronization input/output 2.4. Frame synchronisation As was stated in the in the background section, the message frame will begin with the characters ++++ and the message has 72 bytes encoding the message using a ASCII characters. Therefore, this section will deal with two tasks: (1) Detect the message preamble and (2) Decode byte per byte of the data contained in the payload. After the preamble section, we will detect 576 bits, corresponding to the 72 bytes that correspond to the ASCII characters. These characters will be dumped into an executable file that will then show the message that has been detected and decoded. The specific implementation of the algorithm is attached in the appendix section of this report. 2.5. Results and evaluation The result of applying the steps described in the sections from 2.1 to 2.4, we obtain the message, getting the result showed in the next figure: Figure 16 Result of non-coherent receiver detection 3. Coherent receiver The coherent receiver, also called synchronous receiver, implies certain degree of agreement or knowledge about parameters used in the transmitter side. For the case of the project, we have a signal of type DPSK, i.e. the codification is contained in the variation of the phase of the signal. 3.1. IQ Down-converter The aim of this component is to decompose a complex signal in terms of its in-phase and quadrature elements. To achieve this decomposition, we are going to perform the implementation using lookup-table oscillators, i.e. that for a given signal in-phase and quadrature components will be obtained by using the definitions given by: Figure 17 IQ Downconverter (Tsimenidis, 2016) Upon these definitions, the components that we obtain could be represented in two separated graphs, each one of them representing a different component table. Figure 18 Sine and cosine table graphs As for the index control of look-up table, we decide to use for loop to generate x2I[n] and x2Q[n], storing and transporting data to corresponding files as x2I.h and x2Q.h. These files will be used later to perform the conversion of values. Figure 19 Index control flow (Tsimenidis, 2016) After understanding the principle, we defined all of variables and initialized them to zero inside the main, and select the appropriate value of some variables such as state_mf, coeffs_mf and N_mf.Same as the picture over, the original data from bandpass output is also separated into two filters: Matched Filter I and Matched Filter Q, and the coefficients of the filters are the same with the original one. The benefit of using the lookup-table oscillators (setting x2 into x2I and x2Q) is to decrease the time of simulation because of the lower required sampling rate.ÂÂ   We can use via lookup table method to call them from x2I.h and x2Q.h, so that we can use it more efficiently in Matlab instead of shifting itself. And then, we multiplied x1 to x2I[n] and x2Q[n] one by one by using another for loop and got x3I and x3Q.Besides,the code of matched filter had been given by tutors and got x4I and x4Q. {x4I=fir(x3I,coeff_mf,state_mf_I,N_mf);ÂÂ   //match filter I } {x4Q=fir(x3I,coeff_mf,state_mf_Q,N_mf);ÂÂ   //match filter I } Figure 20 Filter comparison (Tsimenidis, 2016) We monitored and recorded x3I and x3Q in PicoScope and print screen. The wave of them spinning fixed at the origin point so three of these blows were selected to describe this wave batter. Figure 21 Down-conversion: x3I vs. x3Q counter clockwise After this, we can visualize the outputs of each one of the filters, now we are going to plot in the figure x4I and x4Q, obtaining: Figure 22 Down-conversion: x4I vs. x4Q counter clockwise 3.2. Symbol synchronization After IQ down-converter, the next stage is symbol synchronization. To achieve this, we create x5I[n] and x5Q[n] and sent x4I, x4Q one sample at the time. The procedure that we should do in this section is similar to the one seen in the non-coherent detection, however we must consider two buffers instead of one, one for I and other for Q parts. The sum of the above established energies will correspond to the energy that can be seen as the total energy of the signal, which is similar to lab of the symbol synchronization for the non-coherent receiver. The corresponding calculations to obtain the signals after the symbol synchronization process are defined as: Then, plotting the results obtained, we see the following figure: Figure 23 x6I vs. x6Q Due to synchronization problems, we threated the jitter that was causing these inconsistences using the averaging approach, as described in the follows: Figure 24 Averaging approach to overcome the jitter (Tsimenidis, 2016) Figure 25 Code to solve the jitter 3.3. Differential coherent demodulator In this section, we will implement a differential detector, also called a differential coherent demodulator. Figure 26 Principle of the differential detector (Tsimenidis, 2016) At first, we declare and initialize appropriately the required variables and define .In this differential detector, need to multiply ,1 symbol delay by . N N=1 N=2 N=3 After this, we defined x6I_prev and x6Q_prev to deal with this problem and let x6I_prev and x6Q_prev denote the values of x6I and x6Q from the previous symbol. It is very important to initialize them to zero at the declaration because we know . (Tsimenidis, 2016) x6I_prev=x6I; x6Q_prev=x6Q On the same time, dI contains the first two terms which stand for the In-phase part and dQ which contains the last two terms which stand for the Quadrature part. Hard decision is then achieved by deciding whether the dI value is positive or negative, with a negative value indicating that a logic 1 was transmitted which might be used in the next step that is frame synchronization and message detection. Now we obtain the plot showi

Alcohol drinking Essay

The last reason of alcohol drinking among the youth in Hong Kong is tension reduction and it is the most common excuse among them. From a survey result conducted in 2008 by The Hong Kong Federation of Youth Group, about 30% of students increase their pressure index during the beginning of each new academic year. It was found that the high consumption of alcohol is related to the high level of pressure index. And the frequency of drinking depends on how early the students have experienced drinking alcohol. Drinking daily or over consumption of alcohol will lead to a chain of bad impacts. If we drink in a large amount, it will have lifelong negative consequences, including physically and mentally. Drinking can affect thinking capacity and the active attention period will be reduced effecively. Also fatigue may happen easily although only drinking a small amount of alcohol. As a result, it may affect in studies. As we notice that there are many foreign researches about the motivation of drinking but there are only little researches investigate the Hong Kong tertiary students. That means the foreign researches cannot completely reflect the Hong Kong situation due to the different cultural norms of east and west. Also, the education of alcohol management and knowledge are not prevalence in Hong Kong. Therefore, we would like to know about the basal motives of alcohol drinking and the influences of drinking among the tertiary students. And the healthcare stream students in IVE will be our target group. As our target group are studying in healthcare stream, we hypothesize that they are more likely to consider their health and a lower drinking frequency and quantity of alcohol will be found. We also assume that their motivation of drinking are due to peer, environment and social.

P2 and M1 for communication Essay

There are a wide range of skills we can use to communicate for example we send, receive, and process huge numbers of messages every day. But communication is about more than just exchanging information; it’s also about understanding the emotion behind the information. Communication can improve relationships at home, work, and in social situations by deepening your connections to others and improving teamwork and decision-making. It enables you to communicate even negative or difficult messages without creating conflict or destroying trust. Communication combines a set of skills including nonverbal communication, attentive listening, the ability to manage stress in the moment, and the capacity to recognize and understand your own emotions and those of the person you’re communicating with Argyles theory, communication cycle has six different stages that help you communicate you ideas.it also takes into consideration how you put your ideas across e.g. body language. An idea occurs, you have an idea that you want to communicate. Message coded, you think about how you are going to say what you are thinking. You put your thoughts into language or sing language. Message sent, you speak, sign, write or in some other way send a message. Message perceived, the other person has a sense of your message. They hear you words or see your symbols. Message decoded, the other person understands your message or what you have just said. This may not always be easy as they may make assumptions about your words and body language e.g. for example you went to the doctors and the doctor asked what wrong and you reply saying ‘I have a constant pain in my ear’. The doctor would need to keep the conversation going by rephrasing the question to something like so it’s your ear that’s hurting? This is to make sure you understood or got the right answer. Message understood, if all goes well your ideas will be understood. Argyles theory, communication cycle is a very useful thing to use when trying to communicate to sensitive patients. The communication cycle is a very useful cycle as it makes sure that you don’t say anything insensitive or hurtful to the person who is meant to be receiving the information. the communication cycle is also useful because there are a wide range of stages to help you communicate with others which helps you send someone information with them understanding what you are saying for example a doctor telling a patient when there next appointment is they could use the cycle to help them give the patient the information. But what do you think? Here is a diagram  of Argyles theory. Tuckmans theory In Tuckmans theory explains that as the team enters each stage they develop maturity, ability, relationships and the leader changes leadership style to fit in with the group.it also allows the team to look at the stages to see what stage they’re currently at. There are five different individual stages forming, storming, norming, performing and adjouring.Tuckmans stages are all necessary and inevitable in order for the team to grow, to face up to challenges, to tackle problems, to find solutions, to plan work, and to deliver results. Forming, the team is assembled and the task is allocated. The team members rend to behave independently as they don’t know each other and may feel intimidated. Individuals are also gathering information and impressions about eachother. Storming, the team starts to progress, addressing the task by suggesting ideas. Relationships may also be starting to develop. It is also essential that a team has a strong leadership. Depending on the culture of the organisation and individuals the conflict will be more or less supressed. As the team starts to move out of the storming stage they will enter the norming stage. This tends to be a step forward by the team agreeing on the rules and values by which they operate. By now the team should start to trust each other. After the arguments, they now have a better understanding of eachother and are able to appreciate each other’s skills and experience. Performing, at this stage the group will be filled with enthusiasm. The team will be able to function as a unit as they find ways to get the job done smoothly and effectively without inappropriate conflict. Some people don’t get up to this stage Adjouring, when team members are proud of what they have achieved and happy to have belonged together but at the same time they recognise that it is time to move on.tuckmans theory is a very useful theory as it gives you a range of information about team building, group skills and there stages. Overall, Tuckman’s Stages is a balanced group effort. And also shows how they’re progressing by maturing and building relationships. Here is a diagram of Tuckmans theory. Personally I think argyles theory is more effective and important than  Tuckmans theory as he gives you a load of communication skills to help you give people information. so it’s more than likely that the other person will understand the information they’re receiving. I don’t think Tuckmans theory is more important than Argyles because in Tuckmans theory he doesn’t give you much information about communication. But both theories are effective and are useful. Effective communication and interaction play an important role in the work of all health and social care professionals. For example, care professionals need to be able to use a range of communication and interaction skills in order to: work inclusively with people of different ages and diverse backgrounds, respond appropriately to the variety of care-related problems and individual needs of people who use care services, enable people to feel relaxed and secure enough to talk openly, establish trusting relationships with colleagues and people who use care services, ask sensitive and difficult questions, and obtain information about matters that might be very personal and sensitive. Nurses may have used their communication and interaction skills to find out about the symptoms of your health problems or may have given you advice or guidance on some aspect of your health behaviour or lifestyle. website Date Time http://www.studymode.com/essays/p-2-Discuss-The-2-Theories-1360439.html 29/09/2013 23:15 http://www.studymode.com/essays/Argyles-Communication-Cycle-And-Tuckman’s-Interaction-1092710.html 29/09/2013 23:19

A Profile of Paul Williams, Architect to the Stars

During an age when racial prejudice ran strong, Paul Revere Williams (born February 18, 1894 in Los Angeles) overcame barriers and became a favored architect in Southern California. In 1923, he was the first Black architect to become a member of the national professional organization, the American Institute of Architects (AIA), and he rose to become a Fellow in 1957 (FAIA). In 2017, Williams posthumously received the Institutes highest honor, the AIA Gold Medal. Paul Williams was orphaned when he was four — his brother and parents died of tuberculosis — but his artistic talents were supported and encouraged by his new foster family. His non-Black public school teachers, however, gave little encouragement to Williams, citing the perceived difficulties of a Negro pursuing an architecture career within a largely white community. Nevertheless, he enrolled in the local engineering school and graduated in 1919 from the University of Southern California. He went on to New York City to become one of the first Black students to attend the Beaux-Arts Institute of Design, an architectural experience modeled after the curriculum of the Ecole des Beaux-Arts in Paris. Williams was ambitious and self-assured after such rigorous study and especially after winning an important architecture competition when he was only 25. He opened his own practice back in LA when he was 28. As a Black American, Paul Williams faced many social and economic barriers. Williams clients were mostly white. In the moment that they met me and discovered they were dealing with a Negro, I could see many of them freeze, he wrote in American Magazine. My success during those first few years was founded largely upon my willingness — anxiety would be a better word — to accept commissions which were rejected as too small by other, more favored, architects. Much of what we know about Williams process is from this 1937 essay, I Am a Negro. He took to heart what he had been told about clients — that Black people couldnt afford architects and white people wouldnt hire a Black architect. So, he developed tricks to be less intrusive, almost subservient to potential white clients — most famously, he elegantly sketched upside-down to showcase his ideas to white clients while maintaining a physical distance. Perhaps it is this understanding of space that made this architect so successful. He used both physical and psychological tactics — he would consciously stand in a non-threatening posture with both hands behind his back while explaining that he normally doesnt take on projects in the lower price ranges, but hed be glad to offer some ideas. Williams most famously has said If I allow the fact that I am a Negro to checkmate my will to do, now, I will inevitably form the habit of being defeated. Being Black in a segregated industry led Paul Williams to develop salesmanship and become politically active. He joined the Los Angeles Planning Commission and he became the first Black member of the American Institute of Architects (AIA). In 1957, he was the first Black architect elected to the prestigious AIA College of Fellows (FAIA). Paul Williams collaborated with other architects on many of his larger, public projects, most famously for his role in designing the Theme Building at Los Angeles International Airport (LAX). Some of Williams projects were with architect A. Quincy Jones, who worked with Williams from 1939 to 1940. Although the iconic, futuristic LAX structure is high profile architecture, Williams designed thousands of private homes in Southern California — many of the most beautiful houses in Hollywood are sold an resold to the ongoing star-making machine surrounding Hollywood. Williams designed homes for Lucille Ball, Bert Lahr, and Frank Sinatra, and he became close friends with Danny Thomas, for whom he did pro bono work for St. Jude Childrens Hospital in Memphis, Tennessee. While there is no one distinctive look to his buildings, Paul Williams became known for designs that were stylized and elegant. The architect borrowed ideas from the past without using excessive ornamentation. He could make a Tudor Revival mansion look like a manor house on the outside and a cozy bungalow on the inside. Paul Revere Williams retired in 1973 and died in the city of his birth on January 23, 1980 in Los Angeles, California. Although few documents from his practice have survived, architectural scholars have compiled extensive records of Paul Williams life and works, including contracts, letters from clients, plans, and materials related to specific projects. Photographs, bibliographies, and other resources are posted online by the Paul R. Williams Project, coordinated by AIA Memphis, the University of Memphis, and other organizations. In the 1940s, Williams published two small books of plans that have remained in print. Also, author Karen E. Hudson, the granddaughter of the architect, has been documenting Williams life and work. The Small Home of Tomorrow by Paul R. WilliamsNew Homes for Today by Paul R. WilliamsPaul R. Williams Architect: a legacy of style by Karen Hudson, Rizzoli, 2000The Will and the Way: Paul R. Williams, Architect by Karen Hudson, Rizzoli, 1994 (for ages 8-12)Paul R. Williams: Classic Hollywood Style by Karen Hudson, Rizzoli, 2012 Sources Early African-American Members of the AIA (PDF); 2017 AIA Gold Medal, AIA.org; Architect of Hope, St. Jude Childrens Research Hospital; Williams the Conqueror by Shashank Bengali, University of Southern California Public Relations, 2/01/04