Expurgated joint source-channel coding bounds and error exponents

Jonathan Scarlett, Alfonso Martinez, Albert Guillen i Fabregas

Abstract: This paper studies expurgated random-coding bounds and error exponents for joint source-channel coding (JSCC). We extend Gallager's expurgation techniques for channel coding to the JSCC setting, and derive a non-asymptotic bound that recovers two exponents derived by Csiszár using the method of types. Our approach has the notable advantage of being directly applicable to channels with continuous alphabets.