ɪn θˈiəɹi, sˌiːdˌiːˌɛmˈeɪ, tˌiːdˌiːˌɛmˈeɪ ænd ˌɛfdˌiːˌɛmˈeɪ hæv ɛɡzˈæktli ðə sˈeɪm spˈɛktɹəl ɪfˈɪʃənsi bˌʌt pɹˈæktɪkli, ˈiːtʃ hɐz ɪts ˈoʊn tʃˈælɪndʒᵻz pˈaʊɚ kəntɹˈoʊl ɪnðə kˈeɪs ʌv sˌiːdˌiːˌɛmˈeɪ, tˈaɪmɪŋ ɪnðə kˈeɪs ʌv tˌiːdˌiːˌɛmˈeɪ, ænd fɹˈiːkwənsi dʒˌɛnɚɹˈeɪʃən slˈæʃ fˈɪltɚɹɪŋ ɪnðə kˈeɪs ʌv ˌɛfdˌiːˌɛmˈeɪ.
In theory, CDMA, TDMA and FDMA have exactly the same spectral efficiency but practically, each has its own challenges – power control in the case of CDMA, timing in the case of TDMA, and frequency generation/filtering in the case of FDMA.