You need to break up and channel the human wave.
As Arkhaine said terrain will decide the strategy.
A choke point is good and bad as it keeps SEDA from being flanked which is the biggest threat, but it doesn't allow many ways to break up the charge. You'll want to blunt the enemy force as much as possible early on before they get close up.
Artillery and airstrikes will be king. Both must be used to hit the enemy as far away as possible so that the survivors come up in smaller groups. Just beyond that will be a very thick mine field. You'll have mines stretched all along almost to the first line of trenches, but you'll want them thickest just beyond the artillery kill zone and in front of the trenches. The first will be to try to wipe out their morale early on, and the second is to be one last line of defense.
You'll need several lines of trenches just in case, and be ready to blow the trenches as they're abandoned.
You have to hit them hard and keep hitting them until they break.
In open terrain things are more flexible and more dangerous.
Breaking the horde up into more manageable pieces is essential. To break the horde up you need to have time.
Sending out some light forces to lead them off track for a few hours, forcing them to slow down as their scouts are killed, damaging bridges and roads are critical. An airforce would go in and take out vehicles to block roads, try to bomb the supply line so they are on short rations, and finally attack the middle of the convoy trying to break the horde into smaller less United pieces.
With the extra time, the main forces will be laying down minefields. These are to break the wave up into separate channels, so that not every part of the line is hit at once. If the attackers are very poorly supplied you may even consider throwing down caltrops to lame anyone with poor or nonexistent boots.
Barbed and razor wire will be very important in channeling the enemy into the proper lanes and blocking off other parts of the battlefield. Like in WW1, you'll want it in large amounts, thick enough all along to handle dozens of soldiers trying to clip it apart and uproot it.
The clear lanes where you want the enemy charging down will be prepared for artillery and mortar fire, carpet bombing if they have the tech, and heavy weapons.
And after that, entrenched lines with multiple fall back positionsmust be built. If they take a trench it doesn't matter because they have to climb out of it now, and there are five to ten more behind it for the defenders. Also mine the trenches so they can be blown after they're taken. This is especially important when fighting in open terrain.
Flame throwers could be useful for the defence, especially to buy time if forced to retreat. Grenades should be handed out like candy. Heavy machine guns and mortars will give the defenders the best bang for the buck.