The measurement of the muon-pair forward-backward asymmetry A_mumu at the Z pole ( sqrts = 91.2 GeV) will allow the determination of the effective weak mixing angle sin2(thetaW_eff) with an absolute statistical precision of 3 × 10−6 [1]. A 3 × 10−5 relative statistical precision on Aμμ just below (√s ∼ 88GeV) and just above (√s ∼ 94GeV) the Z pole also gives access FB to a direct determination of the QED coupling constant αQED(m2Z) with a similar statistical accuracy, and with experimental uncertainties that can be kept well below this value. Such an accuracy is an essential input to the new physics interpretation of precision electroweak data. A limiting systematic uncertainty comes from QED corrections to the e+e− → μ+μ− process, and in particular from the interference between initial- and final-state radiation (IFI), which modifies very substantially (by a few %) the value of Aμμ . Experimental and phenomenological ways to FB minimize the effect of IFI on αQED(m2Z) and sin2 θWl will be developed and studied, and control of IFI with independent data will be investigated, in order to estimate the requirements on the theoretical precision with which QED corrections need to be computed.