A method for communicating using a configurable bandwidth, comprising: receiving, at a user equipment, UE, (115; 206; 802), a control channel from a serving evolved Node B, eNB, (105; 204; 804), wherein the control channel includes a resource grant for an uplink shared data channel in an allocation space, wherein: the allocation space is divided in time and contains downlink communications, followed by a guard period, followed by uplink communications and includes a plurality of resource block groups in a frequency domain over a plurality of OFDM symbols in a time domain; and the resource grant indicates a number of resource block groups included in the plurality of resource block groups in the frequency domain over a number of OFDM symbols in the time domain starting from a starting resource block group in the allocation space and continuing through the number of resource block groups in the allocation space over the frequency domain first and over the time domain second; transmitting, by the UE, data in the uplink shared data channel in the number of resource block groups; determining an OFDM symbol for transmitting one or more demodulation reference signals, DM-RS, in the allocation space, wherein the symbol is used by a plurality of UEs to transmit DM-RSs; determining one or more resource block groups within the OFDM symbol for transmitting the one or more DM-RSs; and transmitting the one or more DM-RSs in the one or more resource block groups in the OFDM symbol. receiving, at a user equipment, UE, (115; 206; 802), a control channel from a serving evolved Node B, eNB, (105; 204; 804), wherein the control channel includes a resource grant for an uplink shared data channel in an allocation space, wherein: the allocation space is divided in time and contains downlink communications, followed by a guard period, followed by uplink communications and includes a plurality of resource block groups in a frequency domain over a plurality of OFDM symbols in a time domain; and the resource grant indicates a number of resource block groups included in the plurality of resource block groups in the frequency domain over a number of OFDM symbols in the time domain starting from a starting resource block group in the allocation space and continuing through the number of resource block groups in the allocation space over the frequency domain first and over the time domain second; the allocation space is divided in time and contains downlink communications, followed by a guard period, followed by uplink communications and includes a plurality of resource block groups in a frequency domain over a plurality of OFDM symbols in a time domain; and the resource grant indicates a number of resource block groups included in the plurality of resource block groups in the frequency domain over a number of OFDM symbols in the time domain starting from a starting resource block group in the allocation space and continuing through the number of resource block groups in the allocation space over the frequency domain first and over the time domain second; transmitting, by the UE, data in the uplink shared data channel in the number of resource block groups; determining an OFDM symbol for transmitting one or more demodulation reference signals, DM-RS, in the allocation space, wherein the symbol is used by a plurality of UEs to transmit DM-RSs; determining one or more resource block groups within the OFDM symbol for transmitting the one or more DM-RSs; and transmitting the one or more DM-RSs in the one or more resource block groups in the OFDM symbol.